ASSC 14 - Full Program (Including Abstracts)
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program (Titles and Author details only)
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ASSC14 Conference Schedule
Thursday, June 24th
MORNING TUTORIALS (
TUTORIAL 1: Signal detection theory and
distinguishing conscious vs. unconscious
Michael Snodgrass (University of Michigan , USA
Hakwan Lau (Columbia University , USA
Venue: Armoury Suite (2nd
Floor)
TUTORIAL 2: Decoding visual and mental content from
human brain activity
Frank Tong (Vanderbilt
University, USA)
Venue: Lombard Suite (2nd
Floor)
TUTORIAL 3: Neural Basis of Suppression, Repression
and Dissociation
Heather Berlin (Mount Sinai School of Medicine , NY , USA
Michael C. Anderson (MRC Cognition and Brain
Sciences Unit, Cambridge , UK
Venue: Elm Suite (2nd
Floor)
TUTORIAL 4: What are mental representations, and
does the mind need them?
Paula Droege (Penn State , USA
Venue: St Lawrence Suite (3rd Floor)
-- Lunch Break --
AFTERNOON TUTORIALS (
TUTORIAL 5: Attention and Consciousness: Two
Distinct Brain Processes
Naotsugu Tsuchiya (
Alex Maier (National Institute of Health , USA
Venue: Armoury Suite (2nd
Floor)
TUTORIAL 6 - Cancelled
TUTORIAL 7: Informational Measures of
Consciousness: Integration, Causality and State Structures
Igor Aleksander (Imperial College London , UK
David Gamez (Imperial College London , UK
Venue: Elm Suite (2nd
Floor)
TUTORIAL 8: Train your brain ! Understanding and
applying the neurofeedback technique
Kerstin Hoedlmoser (University of Salzburg , AUSTRIA
Manuel Schabus (University of Liège , Belgium
Venue:
ASSC14 Conference Schedule
Thursday, June 24th
-- Conference Begins
OPENING WELCOME (
Olivia Carter
Venue: Colony
Ballroom (2nd Floor)
WILLIAM
JAMES PRIZE (
Winner to be announced
Venue: Colony
Ballroom (2nd Floor)
Talk by the winner of the
William James Prize for the best published contribution to the empirical or
philosophical study of consciousness within 5 years of receiving a PhD.
PRESIDENTIAL ADDRESS (
Venue: Colony
Ballroom (2nd Floor)
What is a First-Person Perspective?
Thomas Metzinger
Johannes Gutenberg-Universität Mainz, metzinge@uni-mainz.de
In the last one or two decades we have all understood that the
"problem of consciousness" is not a single problem, but a whole set
of different epistemic targets - empirical, theoretical, philosophical.
However, there is also something like a remaining “core question”, a central
and unresolved issue: Subjectivity, the fact that our target
phenomenon is almost always tied to an individual first-person perspective. No
other object of scientific research has this property, and this fact creates
all the well-known methodological and philosophical problems. I think the time
is now ripe for a focused and coordinated attack on this core issue in
consciousness research. In my Presidential Address I therefore want to
encourage the scientific community to confront the core of the problem
directly. I will clarify the concept of a first-person perspective, propose a
positive model on the representationalist level of description, and draw the
audience’s attention to a number of already existing empirical windows into the
phenomenon, which we can use as experimental starting points - dropping first
anchors in naturalizing the subjectivity of consciousness.
-- Opening Night Reception
--
ASSC14 Conference
Schedule
Friday, June 25th
KEYNOTE 1 (
Venue: Colony Ballroom (2nd Floor)
Do Animals Make Shopping Lists? Prospection and Planning by Crows and
Children
Nicola S. Clayton
As humans, we spend
much of our time planning for the long-term future, from shopping lists to
pension plans. Traditionally, it has been argued that only humans are capable
of mental time travel, the ability to cast one’s mind forwards and backwards in
time to reminisce about the past and imagine future scenarios. I shall argue,
however, that some non-human animals are also capable of anticipating the
future, at least in a rudimentary form, and surprisingly, some of the most
convincing evidence comes from a member of the crow family, the western
scrub-jay. In this talk I shall also focus on the development of future
planning in young children, and the distinction between episodic projection and
semantic prospection. http://www.youtube.com/watch?v=y_MnwNyX0Ds
-- Coffee Break --
SYMPOSIUM 1 (
Conscious Awareness, Perceptual
Decision making and the Bayesian Brain
Chair: Hakwan Lau
Venue: Colony
Ballroom (2nd Floor)
A dual-route theory of evidence accumulation during conscious access
Stanislas
Dehaene1 & Lucie Charles1
1 INSERM-CEA Cognitive
Neuroimaging unit Stanislas.Dehaene@cea.fr
Evidence
accumulation is a highly successful framework for understanding elementary
psychophysical decisions, but its relation to consciousness is unclear. My
proposal is that evidence accumulation occurs at multiple levels in parallel.
Many processors accumulate evidence towards the specialized categories that
they code for. However, in the proposed dual-route theory of evidence
accumulation, conscious access corresponds to the crossing of a threshold in
evidence accumulated within a higher-level cognitive pathway, at the level of
the global neuronal workspace (GNW), where multiple processors coordinate their
activity and collectively "ignite" into a single coherent representation.
During non-conscious processing, evidence is accumulated locally within
specialized sub-circuits, thus explaining that forced-choice performance can be
above chance, but it fails to reach the threshold needed for global ignition
and therefore conscious reportability. I will propose a simple mathematical
formulation of this theory, as recently published in Delcul et al (Brain 2009),
then illustrate it with experiments drawn from the subliminal masking
literature. The proposed framework can explain the existence of fast erroneous
responses and their subsequent conscious correction. Its predictions are
compatible with recent evidence for "changes of mind" in a motor task
(Resulaj et al., Nature 2009) and are backed up by new evidence from MEG
signals during a masked number comparison task.
Comparing different signal
processing architectures that support conscious reports
Hakwan Lau
Columbia
University USA hakwan@gmail.com
Possibility
1: conscious and unconscious perception are based respectively on two largely
independent information processing channels (and presumably different brain
areas). Possibility 2: conscious and unconscious perception are based on
essentially the same channel, but a late stage of processing in the hierarchy
distinguishes between the two. Whereas possibility 1 has intuitive appeal, I
present computational modeling, brain stimulation and imaging data to support
possibility 2. According to this Hierarchical model, a late stage of monitoring
process estimates the reliability of the perceptual signal at the earlier
stage. Conscious awareness arises when a perceptual signal is subjectively
interpreted to be sufficiently reliable. This model is congenial with the
philosophical notion of higher-order representationalism. Also, it draws
distinction between attention and awareness, and thereby explains interesting
phenomena such as why we seem to have conscious experience for more visual
objects than we can attend to and report about.
Dual route vs. heirarchical models and the
normative role of conscious perception
Imogen Dickie
I will
discuss the significance of the distinction between 'dual route'
(Dehaene/Charles) and 'heirarchical' (Lau) models of perceptual processing for
central questions about the role of conscious perception in justifying basic
cognition. I will motivate what I take to be the most plausible view of
how this justification works. I will then argue that the dual route model is at
least in tension with this plausible view. I will suggest that the heirarchical
model does better, but only if we depart from Lau's preferred 'higher order
representation' interpretation of it.
Models of perceptual decision and Tolstoy's principle of the nature of
consciousness
Ned Block
Even
if, as Lau and Dehaene suppose, consciousness is a decision process, it does
not follow that a higher order view of consciousness is correct. I will
argue that even on a decisional view, the evidence supports better a first
order theory of both the content of consciousness and what makes that content
conscious. Lau supports a hierarchical decision account whereas Dehaene
supports a dual route decision account. As Tolstoy almost said in
the first sentence of Anna Karenina, "Conscious states are all alike;
every unconscious state is unconscious in its own way." The
application to this case is that both models have a role to play in
explaining unconscious perception, but neither are very relevant to conscious
perception.
-- Lunch Break --
CONCURRENT SESSION 1 (
(A)
- Blindsight, eye movements, and
awareness
Chair: Melanie Wilke
Venue: Colony
Ballroom East (2nd Floor)
Yoshida Masatoshi1, Laurent Itti2, David Berg1,
Takuro Ikeda1, Rikako Kato1, Kana Takaura1,
and Isa Tadashi1.
1
National Institute for Physiological Sciences myoshi@nips.ac.jp
2
Computer Science Department,
We investigated residual visually-guided behavior
in monkeys after unilateral ablation of primary visual cortex (V1), to unravel
the contributions of V1 to salience computation. We analyzed eye movements of
monkeys watching video stimuli and a computational model of saliency-based,
bottom-up attention quantified the monkeys' propensity to attend to salient targets.
All monkeys were attracted towards salient stimuli, significantly above chance,
for saccades directed both into normal and affected hemifields. We also
quantified the contribution of visual attributes (intensity, color, motion and
so on) to the saliency-based eye movements and obtained evidence that the
monkeys' guidance of gaze was influenced by color saliency. Here we directly
examined residual visuomotor processing based on color saliency with color
discrimination tasks. In two monkeys after unilateral ablation of V1, the
isoluminant, chromatic stimuli was presented in one of the two positions in
their affected hemifield. The monkeys were rewarded by making saccade to the
target. The CRT monitor (Mitsubishi DZ21) was used for stimulus presentation and
was calibrated with a colorimeter (PR650). The stimuli were defined by the DKL
color space, that is, the luminance axis, the L-M axis and the S-(L+M) axis. In
both monkeys, the correct ratio was significantly above chance for stimuli with
the L-M component and the S-(L+M) component. Control experiments were done to
exclude the possibility that a small luminance difference from background may
contribute to the above-chance performance. When a small positive or negative
luminance difference (<5%) was added to the chromatic stimuli, the correct
ratio was not decreased. On the other hand, the correct ratio was near the
chance level when the achromatic stimuli with the same luminance difference
were used. Our results suggest that unilateral ablation of V1 does not abolish
the computation of color saliency.
Petra Stoerig1
1Institute
of Experimental Psychology, Heinrich-Heine-university Düsseldorf
petra.stoerig@uni-duesseldorf.de
Even though stimuli presented within regions of
absolute cortical blindness are subjectively invisible, patients with
destruction of the primary visual cortex may localize, detect and discriminate
them much better than chance permits. We here exploit this phenomenon of
blindsight to learn whether task-irrelevant stimuli would affect performance in
an attention-demanding rapid serial visual presentation task. Per trial, nine
black letters and one white target-letter appeared briefly at fixation. On 50%
of trials, a gray disc (5°, -.6 log contrast, 300ms) was presented prior to or
simultaneous with the target-letter. This task-irrelevant disc was presented a)
to the blind field, b) to the symmetric position in the sighted field, c) at
low contrast to the same sighted-field position, and d) at no contrast, i.e. as
a blank stimulus, in two patients. 900 trials were given for each distractor
condition. Throughout, the three hemianopic participants named the white
target-letter at the end of each trial. Analysis showed that, in one patient,
overall performance was significantly affected by the high contrast
sighted-field distractor. However, when trials with and without distractors
were considered separately, the high contrast disc in the sighted field, like
the blank disc, had no specific effect on letter identification. In contrast,
blind-field discs increased error rates specifically on distractor trials.
Rather than causing a null effect like the blank stimuli they perceptually
resemble, the blind-field stimuli disrupted letter identification more
effectively than did the sighted-field stimuli. Possibly, top-down attention
fails to blend out the blind-seen distractors. Visual awareness, or the
processes that generate it, may thus help rather than hinder effective
suppression of distractors.
Robert Kentridge1, Jo Mason2, and Charles Heywood1
1
University of
2
University of
A prosopagnosic patient, MS, was tested in a Posner
attentional cueing paradigm using photographs of the faces of two models as
cues. The models were photographed directing their eye-gaze at one of three
peripheral target locations and in a neutral, straight-ahead, direction.
Targets appeared equally often at the three peripheral locations. There was no
contingency between the direction of gaze and target location. As well as
directing their gaze, the models directed their heads equally often at each
target location for each gaze-direction. The task therefore tested how the gaze
direction of another automatically directed attention to a location independent
of head direction. We found the gaze direction, but not head direction, was a
highly effective attentional cue in MS. We tested a range of stimulus onset
asynchronies between cue and target. The effectiveness of the gaze cue decayed
as SOA increased beyond 400ms. This pattern differs from that of normal
observers who persist in being affected by gaze cues at long SOAs in a manner
typical of endogenous curing. Finally we showed that MS could not explicitly
discriminate the gaze direction of the cue faces in a forced choice task,
demonstrating that he was using the gaze cues without conscious experience and
that these cues only drive an exogenous-like attentional process.
Aaron Schurger1,2, Kim Kim2, Anne Treisman2,
and Jonathan Cohen2.
1 INSERM
U992 / NeuroSpin aaron.schurger@gmail.com
2
Fixational eye movements have been shown to play a
critical role in conscious vision by counteracting neural adaptation. Here we
show that fixational eye movements interact differently with first- and
second-order perceptual judgements, at just below the threshold of subjective
visibility. We presented visual stimuli using dichoptic color masking, varying
the color contrast to manipulate awareness of structure in the images. We asked
subjects to guess the stimulus category (face, house) and, after each guess, to
wager on the accuracy of their guess. At a low level of color contrast subjects
remained above chance in guessing the category of the stimulus, although
sensitivity of high wagers to correct decisions was not different from
zero. Using infrared eye tracking we
discovered that this dissociation was tied to opposite effects of fixational
eye movements on guessing and wagering behavior, suggesting that these two
types of decisions may depend on independent processes in the brain.
Nicole Pernat1, Richard LeGrand1,
1
Despite over a century of research, there is still
debate as to whether stimuli presented across the retinal blind spot is
“filled-in” or simply not processed by the brain. Evidence from both perceptual (e.g.,
Ramachandran, 1992b) and neurophysiological (e.g., Fiorani,
Massimiliano Di Luca1, Marc O. Ernst1, and
Benjamin T. Backus2.
1 Max
Planck Institute for Biological Cybernetics
2 SUNY
College of Optometry ben.backus@gmail.com
The
perceptual appearance of a visual stimulus can be changed by presenting stimuli
that are similar, but that differ along specific dimensions, to the observer in
advance. Many negative adaptation
aftereffects are familiar to students of perception, for example. A different example is “cue recruitment”
(Haijiang et al., 2006): a visual signal that has no effect on some attribute
of appearance can often be made to affect that attribute through the use of
classical (Pavlovian) conditioning procedures.
In that case, the signal has come to be treated as a new cue by the
visual system, insofar as it now participates in the construction of some new
aspect of appearance that it previously did not. We asked whether this learning requires that
the signal be visible, i.e. whether it must have a consciously accessible
perceptual consequence, of any sort, during training. To do this we employed an invisible visual
signal, namely, a vertical gradient of vertical disparity obtained by slightly
magnifying the image in one eye. This
signal is measured by the visual system, but it had no influence on any of the
perceptual attributes that observers’ visual systems computed from the
displays, in which horizontal lines depicted a rotating cylinder. During training we made the eye of vertical
magnification (EVM) contingent on the rotation direction of the cylinder. After
training we presented an ambiguous version of the cylinder and found that EVM
influenced the perceived direction of rotation consistent with contingency
during training. Thus, a signal need not be visible for the adult visual system
to give it new use as a participant in the construction of visual appearances. Haijiang, Q., Saunders, J. A., Stone, R.
W., & Backus, B. T. (2006). Demonstration of cue recruitment: Change in
visual appearance by means of Pavlovian conditioning. PNAS, 103,
483–486.
(B)
- Qualia, Phenomenology, and Sensation
Chair:
Allen Houng
Venue:
Colony Ballroom Center (2nd Floor)
George Seli.
D.M. Wegner takes perceived consistency between
volition and act to explain a person’s sense of causing her bodily movements,
along with the other principles given in his Theory of Apparent Mental
Causation: priority (that the agent perceive the volition to occur just before
the movement) and exclusivity (that she perceive no other cause of the
movement). The drawback to Wegner’s conditions, however, is that they
constitute a phenomenological ground for felt agency: If a person is to feel
agentive in the course of action, she must (inter alia) judge her act to be
consistent with her volition during that time. But as I argue, volitions are
typically nonconscious during everyday action: we are simply aware of acting,
and feel agentive in so doing. And even when volitions are conscious, they tend
to be "phenomenologically indeterminate," as T. Metzinger has
observed. Prima facie, these factors would prevent the person from assessing
volition/act agreement. In this paper, I adapt Wegner's theory to address this
problem, arguing that an act agrees with a volition based on the latter's
representational content, which need not be conscious. Positing a nonconscious
consistency judgment, one based on nonconscious volitional content, preserves
Wegner’s intuition that will/act consistency supports the feeling of causing a
movement. Nonconscious volitions also have the theoretical advantages of J.
Searle's intentions-in-action: they explain the difference between actions and
mere movements, and why many actions subjectively appear spontaneous. But their
imperative content and temporal priority to the movement makes them more
suitable than intentions-in-action as causes of movement, as I will
discuss. Furthermore, assuming that
nonconscious consistency assessments regularly occur during action, the
structure of mental processing can reflect -- and arguably supervene on -- a
subpersonal mechanism of action-control, namely the "comparator"
model proposed by several researchers. Thus, on my view, the sense of agency
can serve the cognitive function of indicating operations at nonconscious
levels of action-control, as the product of those operations.
John Schwenkler.
Department of Philosophy, Mount St. Mary’s
University schwenkler@msmary.edu
All perceptual experience is necessarily
egocentric; that is, it locates objects according to a frame of reference
centered on the body of the perceiver. But individuating locations with respect
to oneself does not require an explicit representation of one's own location,
as not all systems of egocentric spatial representation need be self-locating
in the same sort of way as, say, my belief that I am at my desk. But can we do
justice to the phenomenology of human visual experience if we regard it only as
egocentric in the thin sense, and not as self-locating in the more robust one?
I argue that we cannot: there are important aspects of visual experience that
cannot be accounted for unless we take the location of the self to be among the
things that vision represents. I go on to indicate some difficulties raised by
this discovery for neurobiological models of visual perception that treat
spatial distribution in the primary visual cortex as the fundamental source of
visual spatial information; instead, it may be only via feedback from higher
cortical areas that visual space is structured.
Robert Van Gulick.
There are at present
many competing theories of consciousness: philosophical (higher-order,
representational,..), cognitive (global workspace, information integration,
attended mid-level representation....), and neurobiological (local reentrant,
thalamo-cortical loop, synchronous oscillatory.....). Although most are
developed in isolation and some combinations are obviously contradictory,
others might be jointly accepted. Beyond
mere joint consistency, some combinations might be complementary and mutually
supportive. This might occur in at least three ways: 1. Different theories may
describe consciousness at different levels, and a lower level theory may
describe processes or mechanisms that implement those at a higher level: either
within a domain (models at two cognitive levels) or across domains (cognitive
and neurobiological). 2. Different theories may describe separate aspects of
consciousness, each of which needs to be included in a comprehensive account.
These parts or aspects of consciousness may divide at different scales: at the
very macro level, e.g. the supposed distinction between access consciousness
and phenomenal consciousness, or at more micro levels - e.g. the distinction
between conscious and unconscious processing may apply differently with respect
to memory than it does with respect to perception. 3. Two or more models of
consciousness may describe what turn out to be mutually interdependent aspects
of consciousness. Integrating the two theories may provide an important and
useful re-conceptualization of each. The union of the two may transform our
understanding of each in a way that allows us to better see how they together
contribute to the nature of consciousness.
I will provide a quick overview or "map" of some of the
leading philosophical, cognitive and neurobiological theories/models of
consciousness. I will then briefly survey some of the major prospects for each
of the three types of integration among them. I will then focus on one
particularly promising possibility for integration. That option aims to
transformatively combine the reflexive view of consciousness as a form of
self-awareness (whether higher-order or same-order) with global integration
accounts. Both prior theories undergo a significant re-conceptualization in the
process of integration. The integrated account also provides an explanatory
link between access and phenomenal consciousness, and deepens the connections
to various proposed neural substrates.
UENF ggomes@uenf.br
An important question about consciousness is how
long it takes to become conscious of a sensory stimulus. Several experimental
paradigms will be analyzed as possible ways to study this question. Simple
reaction time (RT) is of no avail, since the reaction may occur before the
stimulus becomes conscious. Choice RTs are subject to the same problem, but
under some conditions (to be discussed) may indicate an upper limit for the
latency for conscious sensation (LCS). Donder’s (1868/1969) experimental
situation c, which is the one that comes closer to what would be ideal for this
purpose, has given a mean value of 237 ms for choice reaction time. Some
backward masking experiments, by contrast, may give us an estimation of a
minimum value for LCS. If a stimulus is masked from consciousness by a
subsequent stimulus, this indicates that the subject was not yet conscious of
the first at the time of presentation of the second. Available backward masking
studies suggest minimum values of about 200 ms for LCS. Libet’s method of
pairing a peripheral and a cerebral stimulus provides another way of estimating
this minimum value. However, Libet et al.’s 1979 study presents methodological
problems and was never replicated. Moreover, both its experimental design and
the original interpretation of its results were biased by Libet’s ill-founded
adoption of the backward referral hypothesis. A reinterpretation of his results
indicates a minimum value of 230 ms for LCS. In 1977, Geldard systematically
studied the illusory spacial displacement of a cutaneous stimulus by the action
of a subsequent stimulus. Rather than
supporting the view that consciousness does not occur at a definite point in
time, as Dan Dennett holds, I will argue that Geldard’s results indicate a mean
minimum value of about 210 ms for LCS.
Benjamin D. Young.
Looking at the different theories of
consciousness, one becomes aware that something does not smell right. Olfaction has been neglected. The olfactory
system’s anatomical structure, functional organization, and sensory states
raise problems for the prevailing neuroscientific theories of consciousness,
while providing a novel perspective for theorizing about consciousness. The
anatomical structure of the olfactory system is problematic for the current
neuroscientific theories of consciousness, which consider a thalamic relay or
corticothalamic loops as a necessary condition for consciousness. A thalamic
relay might be necessary for consciously analyzing odorants (Pially, et. al.
2007), but it is not required for consciously discriminating between
odorants. Thus, providing reason to
doubt Crick’s (1984, 1994) theory (Smythies, 1997), Crick & Kock’s (1998)
theory (Shepherd, 2007), Koch’s neurobiological t heory (2004), and the Information
Integration Theory of Consciousness (Tononi & Edelman, 1998; Tononi, 2004).
The functional organization of the olfactory system further aggravates the
problem for these theories, since the necessary thalamic connections cannot be
replaced with a functional equivalence within the olfactory system. Using
research on the mitral cell’s functional encodings of odorants in the olfactory
bulb (Friedrich & Lauent, 2001), I argue that the aforementioned theories
cannot reply that the olfactory bulb plays an equivalent functional role to
that of the thalamus for vision (Kay & Sherman, 2006). Furthermore, the
necessity of cortical connections without thalamic relays for our conscious
sense of smell suggests studying phenomenal consciousness as a necessary condition
for access consciousness. using evidence from Blind Smell (Schwartz, 1994,
2000; Sobel et. al. 1999).
Jennifer Windt.
Johannes Gutenberg University of Mainz windt@uni-mainz.de
A central question for epistemology is how to
prove the reliability of our knowledge of the external world. Subjective
feelings of certainty are central to this type of project in the classical
literature. Examples include René Descartes’ reliance on intuitive,
self-evident propositions and clear and distinct ideas. Visual metaphors of
certainty also abound in John Locke’s Essay Concerning Human Understanding,
where knowledge is defined as the perception of the agreement or disagreement
of ideas. In the first part of the talk, I argue that in these classical
examples, the transition from subjective feelings of certainty to objective
knowledge hinges on the assumption that psychologically irresistible beliefs
are also epistemically reliable (Loeb 1992).
What makes these ideas psychologically irresistible, in turn, is that
their occurrence gives rise to a distinct experiential property, the phenomenology
of certainty. Whereas many agree that
intentional states such as beliefs are not individuated by their phenomenal
content (but see Horgan & Tienson 2002), increasing attention is being paid
to feelings of knowing (Koriat 2000) and so-called noetic (Metcalfe 2000) or
epistemic feelings (de Sousa 2009) as well as their neural basis (Maril et al.
2002). At the same time, the phenomenology of certainty says nothing about the
epistemic justification of occurrent intentional states (or their corresponding
verbal reports): Delusions can give rise to the phenomenology of certainty
while be being profoundly misrepresentational.
I claim that the phenomenology of certainty, including conscious
theoretical intuitions, is not epistemically warranted. This suggests that a
subset of questions traditionally conceived of as belonging to epistemology
should be handed over to philosophy of mind as well as to interdisciplinary
consciousness research. They require a reinterpretation in terms of the
phenomenology of epistemic feelings as well as, ultimately, a functional and
neurophysiological analysis. To the extent that epistemological theories rely
on the phenomenology of certainty to vindicate our epistemic access to the
world without presenting a convincing argument for its trustworthiness, they
must therefore be regarded as inconclusive, or incomplete. This presents a
serious problem not just for classical epistemological arguments, but also for
recent defenses of intuitionism (Goldman 2007; Chudnoff 2010).
(C)-
Implicit Learning: Must we articulate what we (consciously) know?
Chair:
Axel Cleeremans
Venue:
Giovanni Room (2nd Floor)
Zoltan Dienes.
One of the key domains investigating the difference
between conscious and unconscious processes is implicit learning. Within the
implicit learning literature, the key papers defining the “believers’” position
that unconscious learning exists, and its nature, were published by Arthur
Reber in the 1960s and 1970s. The paper defining the sceptics’ position, and
still one of the most closely argued papers sceptical of implicit learning, is
Dulany, Carlson and Dewey (1984) (DCD), the first response to Reber’s papers. I
will present fresh data which, for the first time in 25 years, attempts to
replicate DCD, and test alternative interpretations of their results. I will
argue that Reber’s point of view is vindicated by DCD’s procedure. Reber exposed people to strings of letters,
unbeknownst to subjects generated by a finite state grammar, and then asked
people to classify new strings as obeying the rules or not. People could do so
at above chance levels despite being unable to describe the rules. Reber argued
people had acquired unconscious knowledge. DCD repeated the procedure but asked
people to underline the part of the string that made it grammatical or
non-grammatical. Treating these underlinings as conscious rules, he showed rule
validity predicted correct classification almost perfectly. Thus, DCD argued
that all the knowledge was conscious.
DCD assumed that forced underlining of part of a string amounted to
asserting a rule. But, for example, wondering or completely guessing where to
underline is not to assert anything. I repeated DCD’s procedure but in addition
asked people to report the basis of their underlining: They completely guessed,
they relied on intuition, they used a rule, and they used recollection. People predominantly said they guessed (37%)
or used intuition (30%). Further, DCD’s method for calculating rule validity
artifactually produced the results they wanted – the relation of rule validity
to classification was largely a mathematical given, not an empirical discovery.
When the artefact is corrected, underlinings are still shown to express
knowledge to some degree. Importantly, they do so even when people felt they
were guessing (or using intuition). That is, the underlinings largely expressed
unconscious knowledge.
1 Fonds de la Recherche Scientifique – FNRS jbertels@ulb.ac.be
2 Université Libre de Bruxelles
To what extent does statistical learning occur
implicitly? In visual statistical learning (VSL), participants learn the
statistical regularities present in a sequence of different visual shapes. A
recent study (Kim, Feenstra & Shams, 2009) suggests that visual statistical
learning is not accompanied by conscious awareness of the statistical
regularities between sequence elements.
In a replication of this study, we challenge this interpretation by
showing that participants are able to identify the nature of the statistical
regularities in a 4-alternative forced-choice (4AFC) task in which each trial
also involved a binary confidence judgment. We further observed a positive
correlation between participants’ performance in the 4AFC task and their
confidence in their performance. Our results therefore suggest that the task
used in the initial study may have been too difficult to elicit conscious
knowledge but not that VSL was truly implicit. Participants indeed appear to be
conscious of what they learned and when they applied this knowledge
successfully. Our results will also be
discussed in light of the ongoing methodological controversies in the field of
implicit learning in which the interpretation of the empirical evidence has
flipped between a strong endorsement of an unconscious learning system and the
denial of non-conscious acquisition of new information. To our best knowledge,
Kim et al’s and our study are the first to address this issue in the burgeoning
field of statistical learning.
Robert Balas1 and Joanna Sweklej1.
1
Evaluative conditioning (EC) is a process of
changing the evaluation of initially neutral stimulus (conditioned stimulus –
CS) due to its repeated pairing with either positive or negative stimulus
(unconditioned stimulus – US). As such it is regarded as a basic learning
process that results in forming attitudes and preferences. Conscious awareness
impact on EC is now a question of considerable debate. Specifically, there is
no consensus whether EC requires subject’s awareness of CS-US contingencies as
well as awareness of stimuli themselves. The presented research examines
whether EC is possible without perceptual and contingency awareness. First two
studies examined whether EC is possible with subliminal presentation of the
stimuli. To assess contingency awareness a 4 Picture Recognition Test was used.
This test requires participants to select an
Elisabeth Norman1, Mark Price1, Ryan Scott1,
Emma Jones1, and Zoltan Dienes2.
1
University of
2
University of
Flexible control over the application of knowledge
is traditionally regarded as indicating conscious access to that knowledge
(Baars, 1988). However the dichotomy between implicit/unconsicous and
explicit/conscious knowledge is being softened by suggestions that
consciousness might be graded (e.g., Cleeremans, 2008; Cleeremans &
Jimenez, 2002) and the question of whether flexible control is always
associated with conscious access to knowledge needs to be empirically
addressed. In an artificial grammar
learning experiment (N=72) we investigate whether people show flexible control
over the use of acquired rule knowledge when detailed knowledge of the learned
rules is not conscious. All participants were exposed to two sets of letter
strings, each governed by a different artificial grammar. The nature of the
grammar rules was disguised by random variation in irrelevant stimulus
properties of each letter string. In a subsequent test, participants classified
novel letter strings but were cued on a random trial-by-trial basis as to which
grammar they were assessing. Participants’ awareness of the nature of the
grammar rule was assessed by a combination of free verbal report and a multiple
choice questionnaire. Results showed that participants were able to flexibly
control the application of the two grammars. This applied even to those
participants who did not know which stimulus dimension the grammar rule was
based on. These participants also showed better string classification on trials
where they rated themselves as using “implicit” decision strategies, i.e.,
random choice, familiarity, or intuition.
Results are discussed in relation to different theoretical viewpoints
that could explain how flexibility can sometimes be seen as a property of
unconscious knowledge. According to one such viewpoint unconscious knowledge
can be reflected in conscious “fringe” feelings that can be used to guide
behaviour flexibly (
Ido Amihai1,
1
Neuroimaging studies demonstrate that categorical
processing of faces can occur even in the absence of conscious awareness. However, the extent to which information
about subordinate properties such as gender, age, race or identity can be
extracted without awareness of the perceived stimulus is still debated. Our present experimental results suggest a
need for conscious awareness in the processing of subordinate information. Using the FaceGen Modeller software, we
generated faces that were ambiguous either with respect to gender or to race, and
presented them immediately after prime faces that clearly belonged to a certain
race or gender (an extremely male or extremely female face in the gender
classification task and extremely Caucasian or extremely Asian face in the race
classification task). As previously
reported, when conscious vision was unhindered, the classification of the
ambiguous faces was biased contrary to the category represented by the
immediately preceding prime. In
contrast, no bias was observed when the primes were rendered consciously
invisible via continuous-flash-suppression.
Moreover, we found a correlation between the bias strength and the
exposure time of the prime only when it was consciously visible, indicating
that the processing of subordinate information clearly depends on the amount of
time that a stimulus is subjectively visible.
Previous data show that affective images that are presented below the
threshold of conscious awareness can both activate specific brain regions and
influence the affective judgments of subsequent stimuli, possibly through a neural
route that travels directly from the superior colliculus to the limbic system
and bypasses the visual cortex. Our data
shows that such routes are the exception, and are not available for subordinate
categorization that is based on form aspects of the visual stimulus, such as a
face’s gender and race. Thus, despite the enthusiasm about evidence for
residual categorical processing without awareness, conscious awareness is
required for information extracted from faces to affect behavior.
Dan Lloyd.
Music, according to Edgard Varèse, is “organized
sound.” World music traditions organize
sound according to common principles; the most basic is sparsity:detectable
sound properties are continuous, but music restricts itself to discrete subsets
of scales, timbres, and rhythms, subsets varying across musical niches. Moreover, music displays “1/f” power spectra, with greatest amplitude
at low frequencies (Voss&Clark,1975).
Functional MR signals from the brain display musical properties, a
finding presented here for the first time.
We show musicality through fMRI of 34 subjects, half with schizophrenia,
performing simple tasks (Garrity et al.,2007).
“fMusicality” (musical properties in fMR signals) is measured on six
dimensions, and compared to 1000 iterations, same analysis, using randomly
permuted surrogates of the original data (preserving autocorrelation). In fMRI, fundamental and mean harmonic
frequencies are lower, harmonics are fewer, the pulse oscillates less, and
instantaneous frequencies are lower and fewer, in 94% of healthy subjects and
83% of patients. Moreover, the analysis
distinguishes healthy and ill subjects: patients are less fMusical than
controls, but still unlike surrogate data.
All these contrasts are highly significant, notwithstanding
multiple-comparison thresholding. We
argue that fMusicality arises through distributed dynamics essential to
consciousness. Specifically, fMusicality
reflects temporality, the structural awareness of persistence, change, and
repetition over time (Husserl 1966, Lloyd 2002, 2010). The brain must encode these properties;
fMusicality arises in large recurrent networks.
Accordingly, purported NCCs may be not only multivariate but
polyphonic. Garrity,A.,Pearlson,G.,McKiernan,K.,Lloyd,D.,Kiehl,K.,Calhoun,V.(2007).Aberrant'default-mode'functional
connectivity in schizophrenia. AmJPsychiatry,164:450. Husserl,E.(1966(1928)). Phenomenology of
Inner TimeConsciousness.Martinus Nijhoff.
Lloyd,D.(2002).FunctionalMRI and the Study of Human
Consciousness.JCogNeuroscience,14(6):818.
Lloyd,D.(2010).Neural correlates of temporality:Default-mode variability
and state-dependent temporal awareness.Consciousness Online,
http://consciousnessonline.wordpress.com/ .
Voss,R.F.&Clark, J.(1975).1/f noise in music and
speech.Nature,258:317.
-- Coffee Break --
CONCURRENT SESSION 2 (
(A)-
Priming, Timing, and Neural Coding
Chair: Stanislas Dehaene
Venue:
Colony Ballroom East (2nd Floor)
Ahmad Sohrabi1, Robert West2, and Andrew Brook2.
1 Psychology,
2 Carleton
University
Briefly presented stimuli in a stream can affect
each other. Specially, the first presented stimulus can affect the following
one in terms of the ease and speed of the processing. An example is the priming
effect where the first stimulus (the prime) can affect the second one (the
target). Usually the prime can speed up the RT for the target when they are
congruent (e.g., both require the same response) and vice versa when they are
incongruent, a phenomenon known as Positive Congruency Effect (PCE). However,
in some conditions the opposite effect can occur, i.e., the prime can speed up
the RT for the target when they are incongruent and vice versa when they are
congruent, a phenomenon known as Negative Congruency Effect (NCE). The PCE has
been found with a short interval (e.g., shorter than 100ms) between the prime
and target, i.e., short prime-target Stimuli Onset Asynchrony (SOA) while he
NCE has been found with a long interval (e.g., longer than 100ms) between the
prime and target, i.e., long prime-target Stimuli Onset Asynchrony (SOA). The
NCE has been shown mainly using masked primes but recently it has also been
found with unmasked primes. In this case, the NCE occurs especially when the
prime-target SOA is quite long and the prime is relevant to the task i.e.,
carrying some meanings. Here we simulated our previous experimental data and
others’ on the unmasked stimuli using the same model that we have employed for
masked stimuli only by removing the mask presentation and, in the case of
irrelevant prime, also by putting the mode of the attentional response to the
prime in a less phasic (slightly tonic) mode. The role of the attention in the
model as well as its similar bases in the congruency effects and the
attentional blink will be demonstrated using the dynamic behavior of the
computational units in the model.
Dwayne Pare1, Steve Joordens1, Marc van Duijn1,
and Mina Atia1.
1
University of
Studies involving stimulation of the somatosensory
cortex suggest that electrical pulses at an intensity below some liminal
threshold do not give rise to conscious perception even when trains of pulses
were presented up to 5 s in length (Libet, Alberts, Wright, Delattre, Levin,
& Feinstein, 1964; Pockett, 2002).
These findings seem to imply that a stimulation that does not give rise
to conscious experience simply can never give rise to conscious experience;
that is, conscious experience cannot be primed.
Previous studies have used the process-dissociation paradigm to quantify
the probability of conscious awareness for some item as a result of a single
masked presentation (e.g., Debner & Jacoby, 1994), but no studies prior to
our work have examined the probability of conscious perception as a function of
repetition priming. In our first
experiment we describe a category/exemplar version of the inclusion/exclusion
paradigm. Across two subsequent experiments we then estimate the conscious
perception arising from a single presentation of an item, use that estimate to
predict what would happen if multiple presentations simply led to an additive
increase in the probability of awareness, then compare this prediction to the
observed score. In these initial experiments we find that the additive model fits
the data extremely well, again suggesting no priming of conscious experience.
Given concerns with respect to the potential for ceiling effects affecting our
data, two follow-up experiments were conducted with the intent of keeping the
initial conscious perception of a single presented item to a minimum. This was
achieved across experiments by using non-words in place of the pattern mask and
decreasing the duration of item presentation.
These experiments again provided clear support for an additive priming
effect. This suggests that the
probability that a given presentation will lead to conscious experience remains
unaffected by repetition. Said another way, it appears as though conscious
experience cannot be primed.
Eve Isham1, William Banks2, Arne Ekstrom1,
and Jessica Stern1.
1
2
If an action is thought to be intentional, it is
judged to be closer in time to its result than if it is not intentional. This compression between cause and effect is
termed intentional binding (Haggard et.al., 2002). On the other hand, if an action is
unintended, and instead is prompted by a stimulus, the action is judged to be
temporally closer to the time of the stimulus than to a resultant effect
(Waszak et al., 2005). Our study tested
an alternative hypothesis that the perceived time of an action is not
determined by the degree of intentionality, but by the saliency of the
surrounding events. In Exp1, the participants performed a simple keypress in
response to a visual cue, resulting in one of the two possible tones randomly
selected by the computer. The perceived time of the keypress was the same in
both cases (~241 ms before keypress), illustrating that non-salient,
meaningless tones did not influence time perception. In Exp2, the participants performed the same
keypress but in a competition-like environment where they competed against a
confederate. Each player pressed her own button in response to the cue as in
Exp1. To increase the saliency of the
tones, the participants were told that if they were faster than the competitor,
they would elicit a tone that indicated a win. If the competitor was faster,
s/he would elicit a different tone, implying that the participants had lost.
Deceptively, the participants elicited both tones, and the outcome was randomly
selected by the computer and was not consistent with the actual outcome. The results showed that action time was
perceived to be 21 ms earlier when the participants thought they had won as
compared to when they thought they had lost, p<.002. Furthermore, the averaged perceived time was
124 ms later than that observed in Exp1 (p<.013), suggesting a temporal
shift toward the tone. We attribute these results to the effect of game
outcome, providing evidence that a meaningful post-action event can influence
the direction of a temporal shift and retrospectively modulate the perceived
time of a stimulus-based action.
Noriko Yamagishi1, Eiichi Naito2, Stephen
Anderson1, and Mitsuo Kawato1.
1 ATR
computational Neuroscience Laboratories, PRESTO, JST n.yamagishi@atr.jp
2 NICT,
ATR
High-level cognitive factors, such as states
self-awareness, are believed to play an important role in human visual
perception. The principal aim of this study was to investigate the neural basis
of such processes. To do so we measured cortical activity using
magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI)
while participants were asked to self-monitor their internal attentional
status, only initiating the presentation of a stimulus when they perceived
their attentional focus to be maximal. Their task was to judge the orientation
of a spatially localized Gabor patch. We
employed a hierarchical Bayesian method that uses fMRI results as soft- constrained
spatial information to solve the MEG inverse problem, allowing us to estimate
cortical currents in the order of millimeters and milliseconds. Our results
show that, during self-monitoring of internal attentional status, there was a
sustained depression of alpha activity (7-13Hz) in the rostral cingulate motor
area (rCMA), beginning approximately 450 msec after the trial start (p <
0.05, FDR corrected). We also show that gamma-band power (41-47 Hz) within this
area was positively correlated with task performance from 150 – 640 msec after
the trial start (average of correlation coefficients in this time range, r =
0.71). We conclude: (1) the rCMA is
involved in processes governing self-monitoring of internal attentional status;
and (2) the qualitative differences between alpha and gamma activity are
reflective of their different roles in self-monitoring internal states. We
suggest that alpha suppression may reflect a strengthening of top-down
interareal connections, while a positive correlation between gamma activity and
task performance indicates that gamma may play an important role in guiding
visuomotor behavior.
Shimon Edelman1 and Tomer Fekete2.
1 Psychology Department,
2 Stony
Brook University
Many representational construals of brain
function, including theories of qualia,
identify their explananda with points in a representation space spanned by a set of units (e.g.,
spiking neurons), each of which is
either active or not at any given instant of time (e.g., Smart, 2004). Under this model, the representational
burden is carried by a typically sparse
and ever-changing set of momentarily active units, raising the question of what is it that each
silent unit contributes to one's ongoing
experience. The problem of silent
units is very general: it holds for any approach to cognition that attributes any kind of
interpretation at all to the
instantaneous state of the system in question. This includes, at
the one extreme, the relatively
uncontroversial notion that brain states
represent world states (a standard working hypothesis in neuroscience) and, at the other extreme, the sophisticated
Information Integration theory of qualia
developed by Tononi (2008). While noting
that "it does not make sense to ask about the quale generated by [...] a state (firing pattern)
in isolation" and offering an
intriguing prediction that cooling silent units would leave them inactive, yet alter the subject's experience,
Tononi stops short of spelling out why
this should be the case. According to IIT,
"consciousness can be characterized extrinsically as a disposition
or potentiality -- [...] as the potential discriminations that a
complex can do on its possible states,
through all combinations of its
mechanisms." The need to
invoke potentialities in explaining actual
representational function or experience disappears if these are equated with portions of the system's
state-space trajectory rather than with
instantaneous states or reactive "mechanisms." By making dynamics matter (cf. Chalmers, 1994), our
explanatory move (1) accounts for a
range of neurobiological and behavioral characteristics of conscious experience, (2) gives voice to
silent units, whose very silence is what
makes the trajectory bend the way it does, and (3) points to a computational theory of mind that
is both counterfactually sustainable and
empirically grounded, thereby fixing the sense in which the mind is what the brain does.
Department of Philosophy,
One standard strategy for investigating the
cognitive function of a brain activity is to correlate that activity with task
performance. A new area of research on intrinsic brain activity presents a
challenge for this methodological strategy. Neuroimaging studies show that
subjects who lay awake and still without being given a task nevertheless
exhibit structured brain activity.
Although non-task oriented activity is decoupled from external stimuli,
researchers have identified networks of brain regions that spontaneously
increase and decrease their activity together. This structure suggests that
intrinsic activity might subserve a cognitive function. Since intrinsic
activity is distinguished by decoupling from task performance, however, we
cannot investigate its function directly using cognitive tasks. As a result, it
remains unclear what cognitive function, if any, intrinsic activity
performs. Among the proposed functions
of intrinsic activity are background states of consciousness, such as the
ongoing sense of self, experiences of the body, and the representation of time.
While support for the hypothesis that intrinsic activity subserves background
experience remains speculative, I argue that rigorous use of first-person data
can advance our understanding. Expanding the methodological strategies of
cognitive neuroscience to incorporate first-person data will enable researchers
to test a new range of hypotheses surrounding the relationship between
intrinsic activity and consciousness. I propose a particular type of
introspection appropriate for investigating experiences outside selective
attention: exploratory introspection. Exploratory introspection is unique in
that it enables subjects to report on mental activities that occur in the
absence of a task, without disrupting those activities. I align myself with the
tradition of Neurophenomenology, a research program centered on the rigorous
use of first-person data to identify a precise correlation between experience
and its neurophysiological basis. I suggest that the development of skilled
introspection is an important precursor to meeting what Chris Frith (2002) has
called one of the major scientific projects of our century: “to discover how an
experience can be translated into a report, thus enabling our experiences to be
shared.” I end by showing how
exploratory introspection using trained subjects can meet the problems raised
by incorporating introspection into cognitive neuroscience more generally.
(B)-
Theories of Consciousness
Chair: Anil Seth
Venue:
Colony Ballroom Center (2nd Floor)
Don Borrett1, David Shih1, Michael Tomko1,
Sarah Borrett1, and Hon Kwan1.
1
University of
The goal of synthesizing an agent with phenomenal
experience presents a unique perspective to the study of consciousness that
complements the more prevalent analytical approach. Rather than using the
contents of our experience to serve as a framework to develop a synthetic
phenomenology in a robot, we have suggested using the form of our experience to
define a robot’s phenomenal experience. We take as the fundamental form of
experience a present sensible state that is framed by temporal horizons that
confer meaning to that state. In a robot, these temporal horizons are
identified with the time scales in the controller’s dynamics to which the agent
has access. The time scales are “carried” with the present sensible state in
the controller’s dynamics as the agent interacts with the environment. Data
from evolutionary autonomous agent simulations will be presented and the idea
that simple feedback of time horizons can lead to the evolution of an agent
that can independently determine if its actions are appropriate to the
situation will be discussed. It will also be proposed that the experience of a
world of enduring objects can emerge as a content in the dynamics of an agent
with this form of experience. Breakdown
is the mechanism by which this alternative experience emerges. With this
approach, two types of subjectivity are identified in the robot, the first
person, phenomenal perspective identified with the proposed form of experience and the third person, cognitive
perspective that emerges as an enduring self in the contents of the first
person perspective. The application of evolutionary autonomous agent
simulations to the problem of consciousness provides a unique and complementary
perspective in the understanding of the mechanisms underlying phenomenal
experience.
Igor Aleksander1 and David Gamez1.
1
Imperial College,
In the Information Integration Theory of
Consciousness (IITC), Tononi [1] claims that “…to the extent that a mechanism
is capable of generating integrated information …. it will have consciousness”,
and he describes elsewhere how information integration can be measured in an
arbitrary system. An algorithm that could predict consciousness in the brain
has considerable appeal, but the IITC faces a number of difficulties. One
problem is that the IITC is hard to verify because the calculation of
information integration takes a large amount of computing power - a recent
estimate suggested that it would take ten billion years to analyze a network of
30 neurons. A second issue is that the IITC claims to encompass not only the
quantity of (conscious) information held in a network but also its quality,
i.e. qualia. However, the IITC does not explain how networks’ states can
represent the external world. This
paper introduces a method for assessing the information content of a neural
area that obviates the above difficulties. Our approach treats the network as a
state machine and bases the calculation of information-bearing states on
‘liveliness’, which measures the probability of a connection transmitting
information when the network is in a particular state. This liveliness
calculation scales linearly with the number of connections and takes less than
a second to analyze a network of 30 neurons. To make the states of a neural
complex meaningful we also introduce the notion of ‘Iconic’ training, which
causes a network’s states to represent sensory stimuli (some background in
[2,3]). These adjustments to the IITC should make it more feasible to use the
formalisms of information to develop a scientific theory of consciousness. [1] G. Tononi: “Consciousness as Integrated
Information: a Provisional Manifesto”, Biol. Bull. 215: 216–242. December
2008. [2] I. Aleksander: “Neural models:
Xiaolin Liu1, Jingsheng Zhou2, Anthony Hudetz1,
and Shi-Jiang Li1.
1
Medical College of
2
Converging evidence suggests that the
thalamocortical system is essential in determining the formation of
consciousness. A recent theoretical framework (the information integration
theory) has proposed a compelling view toward understanding the neural
mechanisms underlying consciousness. Specifically, “information and integration
may be the very essence of consciousness.” To the extent that consciousness has
to do with information and integration, the important role of the thalamus to
consciousness is exclusively signified by its rich and highly interdependent
reciprocal connections with the cerebral cortex involving both functionally
specific and nonspecific components. Here, using the resting-state functional
imaging techniques, we examined the specific and nonspecific thalamic
connections in the brain based on the neuroanatomical findings implicating
their respective functional roles in sustaining information and integration.
The participating subjects included seven healthy volunteers and seven
age-matched patients diagnosed with vegetative state, which is characterized by
wakefulness without awareness. The hypothesis we sought to substantiate is that
the specific thalamocortical connections are responsible for functional
specialization (information), which forms sensory representations from the
content about the external world; in contrast, the nonspecific thalamocortical
connections are responsible for information integration that eventually
generate high-order conscious perceptions. Remarkably, our results demonstrated
a consistent division of brain regions such that all the neural correlates that
have been identified in association with high-order conscious perceptions are
either predominantly (e.g., dorsal MPFC, AIC, IFG, ACC), or at least partially
(e.g., PCC, retrosplenial cortex), connected with the nonspecific thalamic
nuclei. Likewise, the specific thalamic connections were consistently revealed
by brain regions presumably responsible for representing information about the
external world. Of these, the nonspecific thalamic connections with the dorsal
prefrontal cortex (PFC) and anterior cingulate cortex for information
integration, and the specific connections with the ventral PFC and precuneus
for gathering information together contribute primarily to the loss of
consciousness in VS. Overall, our results not only endorse the view that the
thalamocortical system is essential to consciousness, but also support the
hypothesis that in line with the information integration theory of
consciousness, brain networks that sustain and integrate information may be
differentiated by the nature of their thalamic connectivity.
Axel Cleeremans.
Consciousness, Cognition &
Computation Group, Université Libre de Bruxelles axcleer@ulb.ac.be
While numerous theories of consciousness have now
been proposed, two big ideas dominate and subsume most other proposals. The
first is that consciousness amounts to “fame in the brain” (e.g., Baars,
Dehaene, Dennett, Lamme): We are conscious of whatever representations have, at
some point in time, come to dominate information processing through processes
of global competition and constraint satisfaction. The other idea is that consciousness specifically
depends on the involvement of meta-representations (e.g., Rosenthal, Perner
& Dienes): We are conscious of something in virtue of the fact that our
first-order representations are the target of higher-order representations. In
other words, it is because of the fact that one is conscious that one is
conscious, that one is conscious! In
this talk I explore the idea that consciousness is something that one learns
rather than an intrinsic property of certain neural states, and suggest that
this perspective offers a way of reconciling Global Workspace Theory with
Higher-Order Thought Theory. Starting
from the idea that neural activity is inherently unconscious, the question
becomes: How does the brain learn to be conscious? I suggest that consciousness
arises as a result of the brain's continuous attempts at predicting not only
the consequences of its actions on the world and on other agents, but also the
consequences of activity in one cerebral region on activity in other regions.
By this account, the brain continuously and unconsciously redescribes its own
activity to itself, so developing systems of meta-representations that
characterize and qualify their target representations. Such re-representations
form the basis of conscious experience, and also subtend successful control of
action. In a sense thus, this is the enactive perspective, but turned both
inwards and (further) outwards. Consciousness is “signal detection on the
mind”; the mind is the brain's (non-conceptual, implicit) theory about itself. I subtend these ideas by exploring
empirical evidence that conscious experience is shaped by learning and through
neural network models that simulate the relationships between performance and
awareness in the different tasks explored by Persaud et al. (2007), which
include blindsight, Artificial Grammar Learning, and the Iowa Gambling
Task.
Tobias Schlicht.
Centre for Integrative Neuroscience tobias.schlicht@cin.uni-tuebingen.de
The scientific and
philosophical investigation of consciousness has focused largely on the task of
explaining what differentiates individual conscious states from unconscious
ones, but, until recently, neglected the various forms of unity that
characterize our conscious experience: Conscious experience is subjectively
unified in the sense that, typically, one experiences oneself as a single
subject of thought and action, and conscious experience is phenomenally unified
in the sense that one’s simultaneous experiences typically occur as
modifications or components of a single global conscious state (Bayne &
Chalmers 2003; Bayne 2010). The fact that consciousness is subjectively and phenomenally
unified puts important constraints on any persuasive theory of consciousness.
Moreover, in light of pathological conditions, the question of what
differentiates unified conscious states from disunified conscious states is an
important one. Despite these
explananda, most current theories of consciousness tend to be atomistic both in
methodology and scope; they take what Searle (2000) calls a building block
approach to consciousness and attempt to explain particular conscious states
individually. The task of this paper is to emphasize the unity of consciousness
as an important yet neglected explanandum, and to put forward an account of
consciousness that provides an answer to the question of what makes a conscious
state conscious while at the same time respects subjective and phenomenal
unity—that is, an account of what it is that unifies fine-grained conscious
states into a single global conscious state. After introducing the forms of
unity, the shortcomings of some popular theories of consciousness with regard
to an explanation of these unities of consciousness are exposed. Finally, an
alternative model is introduced that integrates philosophical theorizing with
empirical models from the cognitive neurosciences.
David Rosenthal.
Contemporary discussions of qualitative
consciousness often assume without argument that mental qualities are always
conscious—or if not that only first-person access can reveal their nature. These assumptions typically rest on the
alleged conceivability of inverted qualities:
If it’s conceivable that your experiences of red objects exhibit the
same mental quality as my experiences of green objects, only consciousness can
tell us about such qualities. This leads
to the hard problem and the conceivability of zombies, thereby threatening a
scientific treatment of qualitative consciousness. But we needn’t individuate mental qualities
by way of consciousness; we can rely instead on the role those qualities play
in perception. Each perceptual modality
enables access to a range of perceptible properties, and we can construct a
quality space that maps the just noticeable differences among the properties
accessible by each modality. Since the
ability to distinguish those perceptible properties rests on the distinct
mental qualities they elicit, those mental qualities must themselves conform to
a quality space homomorphic to that of the corresponding perceptible
properties. So we can individuate mental
qualities by their location in the relevant quality space. Quality inversion is precluded, since
symmetry around any axis would collapse the quality space. This quality-space theory applies to bodily
as well as perceptual sensations.
Since location in a quality space depends solely on discriminative
capacity independent of whether the relevant perceptual states are conscious,
the theory accommodates nonconscious perceptual states, such as those in
blindsight and masked priming. So
additional theoretical resources are needed to explain how properties
identified by location in a quality space lead to qualitative consciousness. I show that we can explain that with the
higher-order theory of consciousness I’ve developed elsewhere; there being
something qualitative that it’s like for one is due to a higher-order awareness
of mental qualities in respect of location in a quality space. The two theories together do justice to our
pretheoretic intuitions about qualitative consciousness. And by individuating mental qualities
independently of consciousness, it disposes of the hard problem and zombies,
and so accommodates a science of qualitative consciousness.
(C)-
Consciousness, Cognitive control, and Beliefs
Chair: Michel Ferrari
Venue:
Giovanni Room (2nd Floor)
Maria Brincker.
Three year-olds cannot pass false belief tests
but 18 month-old infants seem able to understand intentions behind clumsy
unintended actions and predict actions of others based on attributions of false
beliefs. How do we explain these seemingly contradictory findings? Due to the
robust findings of ‘Sally-Anne’-type false belief tests it is typically argued
that children cannot understand and reason about other minds until the ripe age
of 3 ½ and social cognition in smaller kids is accordingly dismissed as
non-representational operant learning. Others argue that small children do have
some understanding of mental states and that verbal difficulties rather than
failure of perspective taking underlie the notorious inability to pass false
belief test. Both interpretations seem
unsatisfactory to me. The false belief tests indicate a radical cognitive
development around the age of 3 ½-4, but I argue that it is not attributable to
the sudden appearance of a ‘Theory of Mind’ module but rather the ability to
‘decouple’ from ones own pragmatic perspective or ‘affordance structure’. Thus,
I argue that smaller children do understand other minds but cannot reason or
predict from the perspective of another other if that means disregarding their
own affordance perspective. I point to
developmental and neurological findings, which support the relation between
performance on Sally-Anne-type tasks and the developmental timing and neural
underpinnings of the ability to disengage ones own perspective. I then analyze the rather different social
affordance structures of the difficult Sally-Anne type tasks and the infant
looking time and action completions paradigms where small kids seem to show
social understanding. I hypothesize that typically developing children and
children with autism, who all are incapable of passing the Sally-Anne task show
different patterns of social abilities such that the typically developing kids
on my view should be able to understand others as along as they are not asked
to leave their own perspective. I propose experimental paradigms that could
test my proposals, and finally I point to some broader consequences for how we
understand minds, mental states and their perceptual accessibility and inaccessibility.
Simone Kuhn1, Juergen Gallinat2, Gottfried
Vosgerau1, Patrick Haggard1, and Martin Voss2.
1 ICN,
UCL
2
Department of Psychiatry,
In our everyday phenomenal experience, it is seems indubitable that the
thoughts we experience are our own thoughts. Accordingly, the
claims that we are the authors of our own thoughts and exercise authority over
them were taken as a priori truths (Descartes 1641). However, the phenomenon of
thought insertion in schizophrenic patients has been considered an empirical
proof that these claims are false (
Steve Joordens1 and Sarah Uzzaman2.
1
University of
2
University of
Whyte (1960) described consciousness as a
self-defeating process similar to that of a fever; a process that is awakened
when normal functioning is disrupted, and whose primary goal is to eliminate
itself by correcting the disruption.
This fascinating notion has received little scientific scrutiny to
date. In the present paper we first
describe how this notion fits well with recent findings attributed to memory
binding, and then present three experiments that test the notion further. The experiments show that when discrepant
(i.e., unexpected) events occur in an otherwise predictable context, other
stimuli present at the time of the discrepancy are remembered better. These findings fit with the notion that
discrepancies give rise to cognitive binding, a process by which all aspects of
a stimulus array are bound together, including aspects that were assumed to be
irrelevant to task performance. This
binding process results in memory enhancement, but its core purpose is likely to
provide more accurate predictions in the future, predictions that take into
account background information in a way assumed to reduce discrepancy. To the extent that the accuracy of these
predictions is increased, future discrepancies are reduced, which will then
obviate the need to awaken consciousness in the future.
Carolyn Suchy-Dicey.
Whether active and passive, top-down and bottom-up, or endogenous and
exogenous, attention is typically divided into two types.
This division has led to confusion about whether attention is necessary for
conscious perception, memory, and perceptual learning. That is, when
researchers attempt to show the relationship between attention and other
functions, they need to show whether the type of attention they are researching
is of the active or passive variety. However, the division between active and
passive is not sharp in any area of consciousness research. In phenomenology,
the experience of voluntariness is taken to indicate activity, but this
experience is often confused with others. In psychology, task-dependent
behavior is taken to indicate activity, but is often conflated with complex
automatic behavior. In neuroscience, top-down processes are taken to
exclusively indicate activity despite the fact that both top-down and bottom-up
activations are always present in the brain.
Moreover, work in attention has shown that the results of so-called
passive and active processes are sometimes inseparable. Carrasco, et al., for
example, show that active attention results in the same change in perceptual
contrast that is enacted by bottom-up mechanisms. Likewise, Reynolds and
Desimone show that top-down and bottom-up attention effect neural contrast in
the same way. Thus, the passive-active distinction does not seem to neatly
separate two types of attention. A more
convincing model of attention combines active and passive processing into a
single mechanism of control. One such potential model is what I call the
Unitary Saliency Map Model, first suggested by Koch and Ullman and developed by
Treue. In such a model, top-down and bottom-up processes each feed into the
same saliency map, from which attention is controlled. Thus, active and passive
processes are in a state of competition and balance, rather than run in
parallel. I argue that this makes sense of the phenomenological, psychological,
and neuroscientific data. Finally, the acceptance of such a model will force us
to review some of our previous findings on attention and its relation to
consciousness.
Kevin C. Dieter1, Michael D. Melnick1, and
Duje Tadin1.
1
University of
Binocular rivalry is a form of visual ambiguity
that occurs when dissimilar images are presented to each of the two eyes.
Despite unchanging visual stimulation, perception fluctuates between the two
possible interpretations of the input, suggesting that the mechanisms involved
in binocular rivalry may ultimately give rise to our visual awareness. Although
these fluctuations in awareness are often described as uncontrollable, recent
studies have established that attention can modulate rivalry dynamics,
indicating some degree of internal control. Here, we examined whether prolonged
internal control of rivalry alternations can have a lasting effect on
fluctuations in awareness during rivalry.
In our training experiment (12 30-minute sessions), subjects viewed a
flickering bullseye stimulus presented to one eye (trained eye), and a rotating
pinwheel stimulus presented to the other (untrained) eye. Whenever the bullseye
was dominant, subjects were instructed to identify slight changes in its aspect
ratio. We found that this attentionally demanding task increased dominance
durations of the attended stimulus, replicating previous results. However, the
strength of this effect was not stable, gradually increasing over the course of
training. Additionally, training shortened dominance durations of the
unattended stimulus, ultimately resulting in a strong predominance of the
attended stimulus. Results from a
battery of pre- and post-training conditions revealed that the observed
training-induced changes in rivalry exhibited a considerable degree of
eye-specificity: post-training predominance of the attended stimulus was the
strongest when it was presented to the trained eye. We also measured the
transfer of training to stimuli not used during the attentional task
(horizontal and vertical gratings) and found increases in the predominance of
the grating presented to the trained eye.
In sum, we show that prolonged attentional control can have strong
effects on low-level mechanisms involved in binocular rivalry. Importantly, the
post-training changes in rivalry dynamics were observed even when attention was
not biased toward one of the rival stimuli, demonstrating broad plasticity that
also extended to untrained stimuli. These novel results indicate that
internally guided control of binocular rivalry can lead to changes in the very
mechanisms that give rise to experienced fluctuations in awareness.
Nikolaos Makris1 and Dimitris Pnevmatikos2.
1
Democritus University of
2
University of Western
Despite the explosion of scientific interest in
both consciousness and executive control during the last decades, there is
little research on the way these affect actual behavior. The present study,
which aims to contribute to this limited body of research, examined (a) if
children are consciously aware (CA) of the cognitive processes used to solve
different types of problems, (b) which is the relation between this awareness
and executive control (EC), and (c) how this awareness together with EC affect
cognitive performance (CP). To this end, 138 participants, equally drawn among
9 –through 12-year-old were examined. They were asked to solve 8 cognitive
tasks addressed, in pairs, to the spatial, verbal, quantitative, and causal
domain of thought. Also, they were given descriptions of three different
component skills for each of the domain of thought and were asked to specify
whether each of these component skills was used during the processing of each
of the tasks. For the determination of the level of their executive control,
participants were tested with Visually Cued Color-Shape Task as well as with a
series of Stoop like tasks. Participants were tested individually. Results
indicated that there is an effect of age on the three parameters described
above. Confirmatory factor analyses applied on the data showed that the model
that had an excellent fit on the data was the one indicating the existence of
three general factors. One of them represented the various measures of EC, the
second represented CA about the processing of the various tasks, while the
third one represented the actual CP. Interestingly, it was found that the CA
factor was regressed on the EC factor, while there was a bidirectional relation
between the CA factor and the CP factor. On the basis of these findings it is
suggested that EC affects the CA with respect to the cognitive processing
demonstrated at a given time and that CA affects and it is affected by the
quality of CP. We speculate that these findings are important for a general
theory about the functioning of the mind as well as for practical reasons.
ASSC14 Conference Schedule
Saturday, June 26th
KEYNOTE 2 (
Venue:
Colony Ballroom (2nd Floor)
Image and Message in Sensory States
Mohan Matthen
The
content of a mental state is the state of affairs that it
envisages. A visual state, for instance, may inform us of the presence of
a blue disc somewhere off to the left – this is its content. Sensory
states carry content imagistically – the subject is presented with a
spatiotemporally connected array of features and objects in which each feature
is encoded by a characteristic experience. Thus, a subject who has a visual
impression of a blue disc will see it as a part of an array in which this disc
has location relative to everything else in the array. Further, the
subject’s experience of the disc will be experientially similar to that of
every other blue thing she does or has experienced, and also similar (though in
another respect) to every other presentation of a disc. Now, this
imagistic mode of presenting content has certain formal limitations, which is
illustrated by the following conundrum. Consider (a) a visual perception,
(b) a memory, and (c) an imaging of a blue disc. All can involve the same
image. Yet, the messages they convey are different: (a) carries
the idea that the blue disc occurs now, (b) that it occurred in the
past, and (c) that it is unreal. How do these states convey
these differences? Not by the sensory image, because it is a
common element. I propose to solve this problem in two complementary
ways. From a psychological point of view, the problem just posed
indicates that there has to be a significant component of sensory states
different from the image they present. I propose that a sensory image is
generated by a sensory system, but is then taken up and used by other
systems. The signature of the user-system provides the additional component
we are searching for: for instance, the fact that the memory system is using an
image marks that image as past. From a logical point of view, I exploit
the distinction between content and force. The fact that a particular
system is using an image gives it a certain force that accounts for the extra
element.
-- Coffee Break --
SYMPOSIUM 2 (
Possible Contributions of Research
on Meditation to the Neuroscience of Consciousness
Chair: Antoine
Lutz
Venue:
Colony Ballroom (2nd Floor)
Focused
Attention, Open Monitoring and Open Presence:
Three Styles of Meditation and their Relevance for the Study of
Consciousness.
John D. Dunne
Research on meditation offers a
promising methodology to robustly align third-person and first-person accounts,
and hence, to examine various features of human consciousness. The great
diversity and complexity of meditation practices, however, crucially requires
the formulation of rigorous constructs that highlight the commonalities within
otherwise divergent styles of meditation. Drawing in part on Buddhist theories,
this talk examines two especially useful constructs of this kind: Focused
Attention (FA) and Open Monitoring (OM). In
Impact of Meditation
Training on Attention and Emotion Regulations: Implications for the Study of
Consciousness.
Antoine Lutz
University of
Wisconsin-Madison, alutz@wisc.edu
The first part of this talk will explore possible
methodological motivations for the neuroscientific examination of meditative
practices, such as the alleged increased ability of long-term practitioners to
generate more stable and reproducible mental states and to describe these
states. Using a ‘neurophenomenological’ approach, the practitioners’
introspective skills may provide a way for experimenters to better control,
identify and interpret large-scale integrative processes in relation to
subjective experience. The second part of this talk will offer a
neuroscientific framework for the phenomenological constructs of FA and OP
meditations as presented by Dr. John Dunne (speaker 1). Key neuroimaging
findings will be presented to illustrate how intensive training in meditation
can affect mental processing and the brain.
Effects of intensive
mental training on the temporal dynamics of access to consciousness in the
attentional blink
Heleen Slagter
The main focus of this talk will be on findings from a
study on
the impact of three months of intensive meditation training on visual awareness
as measured by electroencephalography and an attentional-blink task.
Intensive meditation training resulted in a smaller attentional blink, reduced
brain-resource allocation to the first target, as reflected by a smaller
T1-elicited P3b and enhanced bottom-up attentional processes, as reflected by
an enhanced phase-consistency of the second target over right ventral and
midline frontal electrodes. These data increase our understanding of the
conditions necessary for conscious stimulus perception and support the idea
that meditation can significantly affect stimulus processing in the brain. This
talk will also briefly discuss the methodological challenges that researchers
face when attempting to control, or characterize, the multiple factors that may
underlie meditation-training effects.
-- Lunch Break --
POSTER SESSION (
Titles and Abstracts listed after the final talk sessions
Venue:
St Patrick & St David rooms (3rd Floor)
-- Coffee Break --
CONCURRENT SESSION 3 (
(A)- Attention, Rivalry, and Illusions
Chair: Hugh Wilson
Venue:
Colony Ballroom East (2nd Floor)
Jérôme Sackur1, Vincent de Gardelle1, and Sid Kouider1.
1 LSCP jerome.sackur@gmail.com
Perception of orientations is known to be
anisotropic: sensitivity is greater near the cardinal (horizontal and vertical)
axes. This “oblique effect” results in the illusory perception of exaggerated
tilts near the cardinal axes. Here, we quantified this illusion at various
visibility levels, from subliminal to clearly perceived stimuli. We engaged
participants in an orientation reproduction task on a Gabor stimulus whose
visibility was manipulated by duration and masking. We found, first, that
participants could reproduce the orientation of subliminal stimuli, a form of
blindsight. Not surprisingly, precision of orientation reproduction was
positively correlated to awareness. However, we also found that the magnitude
of the oblique effect followed a non-monotonic pattern, being maximal for
stimuli of intermediate visibility, and lower for subliminal and fully
perceived stimuli. These results reveal that subliminal processing, although it
is noisier, can be more faithful to the physical input than supraliminal
processing. This counterintuitive result show that mechanisms of sensory
integration depend on consciousness, and further suggest that categorical
processing of sensory information may depend on stimulus visibility.
Steven Miller.
Perceptual and Clinical Neuroscience Group,
The phenomenon of binocular rivalry is widely
touted as a useful tool in the scientific study of consciousness. Binocular
rivalry involves perceptual alternations of incongruous images presented
separately, one to each eye, in the same retinal location. The mechanism
underlying this remarkable feature of visual processing remains unknown, with
relatively few models available for testing. I review one highly testable
binocular rivalry model and the brain stimulation data on which it rests (1).
In addition, I explain the link between this model and the finding of slow
binocular rivalry in bipolar disorder, a highly heritable psychiatric condition
(2). I also present recent findings from a large twin study, showing that the
rate of binocular rivalry is substantially genetically determined (3). This
finding supports the notion of using slow binocular rivalry as an endophenotype
for bipolar disorder, and suggests new directions in the study of binocular
rivalry. I conclude by outlining how the findings from binocular rivalry
research do, and do not, inform the scientific study of consciousness (4). [1]
Miller et al, (2000). Current Biology, 10 (7): 383–392. [2] Miller et al, (2003). Psychological
Medicine, 33 (4): 683–692. [3] Miller et
al, (2010). Proc Natl Acad Sci USA, 107 (6): 2664–2668. [4] Miller (2007). Acta Neuropsychiatrica, 19
(3): 159–176.
1 Hammel
Neurorehabilitation and Research Centre krissand@rm.dk
2 ICN,
Binocular rivalry has been widely used as a tool to
determine neural correlates of conscious percepts that are independent of
changes in physical stimulation. In the present study, we asked: (1) At which
time point after the onset of rivalry stimuli do the rivaling neural signals
start to diverge consistent with the contents of conscious perception? (2) Can
baseline neural activity before stimulus onset be used to predict the content
of the subsequent percept after stimulus onset? We recorded neuromagnetic
signals using a 275-channel MEG scanner, while human participants were
presented with a face to one eye and a grating pattern to the other and indicated
their percept via a button press. The stimuli were presented intermittently
(800ms on and 1000ms off) to examine the signals triggered by stimulus onset
and the baseline signals before stimulus onset. Behaviorally, our results
replicated previous findings that the subjective percept remained highly stable
across intermittent exposures to the bistable stimuli i.e. percept
stabilization occurred. To determine the time points at which recorded neural
activity was predictive of subjective conscious perception, we performed
multivariate pattern classification analysis on multichannel neuromagnetic
signals at each time point. The pattern
of the evoked neuromagnetic activity at early time points reliably predicted
the content of conscious percepts; we observed a large peak with 85-90%
prediction accuracy at around 200ms after rivalry onset. The pattern of neural
activity during the blank interval also predicted the subsequent conscious
percept better than chance lending support to the idea that sustained, stimulus-specific
activity in the blank period may be responsible for the perceptual memory known
to persist across intermittent exposures to bistable stimuli. Taken together,
our findings demonstrate that the contents of conscious percepts can be decoded
from MEG signals on a trial-by-trial basis. This approach allows us to identify
the temporal dynamics of the emergence of neural activity corresponding to
conscious percepts with a high temporal precision.
Jeroen van Boxtel1 and Christof Koch1.
1
Caltech jeroen@caltech.edu
Currently, it is believed that a stimulus is
visible as long as it has a surface signal (which is the signal that is
perceived) surrounded by a strong-enough boundary signal (which itself is not
visible). Without a strong boundary
signal the surface signal dissipates and the stimulus fades from awareness. One problem with this hypothesis is that the
border signal is experimentally (and conceptually) confounded with the
visibility of the stimulus. Because the boundary signal has never been
experimentally separated from the visibility of the stimulus, the core of the
hypothesis has not been tested. To circumvent this problem, we simply
physically present a ring on the screen surrounding the afterimage. This ring
will provide a strong boundary signal.
We show that the duration of the afterimage is lengthened by about 50%
with a ring that exactly encompasses the afterimage. Rings of equal or smaller size than the
afterimage increase afterimage duration relative to a condition without a ring,
while boundaries larger than the afterimage do not increase afterimage
duration. We find furthermore that maximum modulation occurs for intermediate
contrasts of the ring, making attentional capture (by large luminance changes)
an unlikely cause of the effect. Thirdly, placing a ring around the position of
an already faded afterimage, revives the afterimage. Finally, we modulated the
amount of attention paid to the adapting stimulus. We found that both boundary
and surface signals were more adapted with increased amounts of attention.
Interestingly, increased adaptation of the boundary signal led to decreased
afterimage durations, while increased adaptation to the surface signals led to
increased afterimage durations. Our data
show that boundary signals (i.e. the ring) are crucial in the determination of
afterimage perception. We also show that attention acts on both surface and boundary
information, and that it has the capability to both increase and decrease
afterimage duration.
David Carmel1, Jeremy Thorne2, Geraint Rees1,
and Nilli Lavie1.
1
Psychology and Center for Neural Sciences,
2
Increasing attentional load has been shown to
reduce processing and awareness of visual stimuli outside the focus of
attention. The mechanism underlying these effects, however, remains unclear.
Here we tested an account attributing the effects of attentional load to
modulations of visual cortex excitability. Unlike stimulus competition
accounts, which propose that effects of load should be found only when stimuli
are presented simultaneously, the visual excitability account makes the novel
behavioral prediction that attentional load should affect detection sensitivity
when stimuli are presented sequentially as well as simultaneously. In four
experiments, participants fixated a stimulus stream, responding to the
appearance of occasional targets. In different blocks of trials, targets in the
fixated stream were defined by either a color feature (low load) or color and
orientation conjunctions (high load). Additionally, participants responded to
the critical stimulus – a second type of target, presented occasionally in the
periphery (never at the same time as a target in the fixated stream).
Increasing attentional load at fixation reduced detection sensitivity to
critical stimuli, and this effect was similar regardless of whether critical
stimuli were presented simultaneously with central stimuli or on their own, in
an otherwise empty time interval. The effect of load was not apparent in a
control condition where the critical stimulus was presented after processing of
the fixated stimulus was over, ruling out effects of strategic task
prioritization. These findings support a cortical excitability account for
attentional load and challenge stimulus competition accounts.
1
The brain processes information coming from the
different senses in a highly interactive manner. For example, silent
lip-reading activates the auditory cortex (Calvert et al., 1997). Such
cross-modal interactions are common and widespread, but only a minority of
individuals (with synaesthesia) may exhibit sufficiently intense activation to
warrant a vivid perceptual experience in a second modality when another is
stimulated. The current study focuses on a sensory modality that received very
little attention in the cognitive neuroscience literature - taste. First, we
examined whether the gustatory cortex can be activated by visual stimuli. Using
functional MRI we demonstrated gustatory cortex activation in normal perceivers
viewing videos of people eating. Second, we documented a novel variant of
synaesthesia that appears to represent a perceptual correlate of such cross
activation from vision to taste. Such ‘mirror-taste’ synaesthetes automatically
experience vivid taste imagery when viewing other people eating, analogous to
‘mirror-touch’ in which people have tactile experiences when viewing others
being touched (Blakemore et al, 2005). We are currently investigating the
extent to which this synaesthetic experience is associated with increased
gustatory cortex activation and the mirror neuron system.
(B)-
Body Perception, Cognitive Control, and Awareness
Chair:
Mel Goodale
Venue:
Colony Ballroom Center (2nd Floor)
Timothy J. Lane1 and Caleb Liang2.
1
Research Center for Mind, Brain, and Learning,
2
Department of Philosophy,
We suggest that mental ownership and body ownership
are distinct. The former concerns
whether I represent myself as the unique subject of multiple experiences; the
latter concerns whether a body part (e.g. a hand) belongs to me. This distinction is illustrated by cases of
somatoparaphrenia wherein tactile sensations are experienced in a limb that is
felt to be alien (Moro et al. 2004).
Tsakiris (2009) proposes a neurocognitive model (NCM) of body ownership
that attempts to accommodate research on the rubber hand illusion (RHI). He postulates a pre-existing, normative body
model that contains a reference description of the body’s visual, anatomical
and structural properties. But he
neglects mental ownership. According to
NCM, during RHI induction, in addition to assessing visual-tactile sensory
input, the body model also assesses visual form, as well as postural and
anatomical features. Here we argue that:
(1) Recent findings (Ehrsson 2009, Petkova and Ehrsson 2009, and Armel and
Ramachandran 2003) suggest that NCM confronts several anomalies. (2) These anomalies suggest that Tsakiris
seems to have overemphasized the influence of what we call a body-likeness
principle (BLP), e.g. visual similarity in form and anatomy. (3) Successful induction of RHI requires that
the subject represents himself as the unique subject of conflicting
experiences. This, the mental ownership
constraint (MOC), is needed to explain how RHI is induced by vision’s trumping
of proprioception and tactile sensation.
(4) MOC provides greater flexibility, allowing a revised NCM to
accommodate the three anomalies as well as to motivate new variants of
RHI. Finally, (5) recognition of MOC
will enhance our ability to investigate relationships among NCM, phantom limb
(Giummarra et al. 2005), and full-body illusions (Blanke and Metzinger 2008).
Jakob Hohwy1 and
1
Philosophy, SOPHIS,
The rubber hand illusion, in which touch is
experienced on a rubber hand, poses a puzzle for understanding the
relationships between bodily self-awareness and perceptual inference. In this
study, we use virtual reality goggles to develop a version of this illusion and
use psychologically induced temperature changes of the experimental hand as
objective evidence of presence of the illusion. We explore what happens to body
image and causal inference as new stimuli are presented after onset of the
basic illusion. We present data showing that people easily experience everyday
objects, or even empty space, as loci of projected touch, and they report that
it is as if there are supernatural causal relations between rubber hands and
remote objects. These findings are interpreted in a probabilistic framework. By
drawing on analogies from other areas of multimodal sensory integration, we
show how this framework can explain crucial puzzles about why the illusion
arises. We propose that bodily self-awareness in cognitive processes is
fragile: its role is more subject to and in the service of perceptual
inference, rather than exclusively the other way around. The notions of body
schema and body image are discussed in the light of this proposed bayesian
notion of bodily self-awareness.
Alisa Mandrigin.
The rubber hand
paradigm and globalizations of the illusion are used to probe our experience of
our bodies. Some interpret the experiments as giving insight into bodily
self-consciousness, self-specificity and embodied subjectivity through the
manipulation of the sense of body ownership. I argue that these claims confuse
the sense of body ownership and one’s sense of bodily subjectivity, two
different forms of self-experience that might both be manipulated in these
illusions. In the RHI subjects report
the feeling that a haptic sensation they experience is felt in a rubber hand, a
sensation induced by synchronous stroking of their own unseen hand and the
perceived rubber hand (Botvinick & Cohen 1998; Tsakiris & Haggard
2005). It is claimed that the manipulated sense of body ownership is a
component of one’s s self-specific subjective perspective (Tsakiris 2010). Global versions of the illusion involving
either virtual representations (Lenggenhager et al. 2007) or real-time video
images (Petkova & Ehrsson 2008) seem to indicate that one’s sense of body
ownership can also be distorted on a larger scale. The controversial claim is
that the experiment probes bodily self-consciousness (Blanke & Metzinger
2009). I urge that we clarify the
difference between the sense of ownership and one’s sense of bodily subjectivity.
The body is both something that is owned in our experience of it, and something
that is lived-through. The relationship between body and subject is one of
ownership, in perception of the body, and one of identity - the perceiving
subject is bodily. One’s sense of bodily subjectivity is a precondition of one
having a sense of ownership of one’s perceived body. This distinction is significant because of
the possibility that the experiments manipulate, to different extents, both
one’s sense of body ownership and one’s bodily subjectivity. Legrand (2006) and
Legrand & Ruby (2009) suggest that bodily subjectivity results from
sensorimotor integration, whilst it has been suggested (Tsakiris 2010;
Leggenhager et al. 2007) that one’s sense of body ownership depends on
multisensory integration. Manipulation of sensory integration may therefore
affect both the sense of body ownership and one’s sense of bodily subjectivity.
Andre Keizer1, Maurice Verschoor2, Roland Verment1,
and Bernhard Hommel1.
1
University of
2
Neural synchronization has been proposed to be the
underlying mechanism for exchanging and integrating anatomically distributed
information. Here we studied whether neurofeedback training designed either to
increase gamma band activity (GBA), or beta band activity (BBA), would have an
impact on performance of behavioral tasks measuring short-term and long-term
episodic binding. Our results show that GBA-enhancing neurofeedback training
increased frontal-occipital GBA and BBA-enhancing neurofeedback increased
frontal-occipital coherence in the beta band. Moreover, the increase of gamma band
power was related to greater flexibility in handling episodic bindings. The
long-term memory task revealed a double dissociation: GBA-targeted training
improved recollection, whereas BBA-targeted training improved familiarity. We
conclude that GBA is important for controlling and organizing memory traces of
relational information in both short-term binding and long-term memory, while
frontal-occipital coherence in the beta band may facilitate familiarity
processes.
Tristan Bekinschtein1, Ram Adapa2, David K. Menon1,
and Adrian M. Owen1
1 MRC
Cognition and Brain Sciences Unit tristan.bekinschtein@mrc-cbu.cam.ac.uk
2 Division
of Anaesthesia,
When people receive anesthetics (propofol in this
case) they enter the dynamic process of changing from fully aware (sedation
level S0) to a relaxed state (sedation level S1) to drowsiness (sedation level
S2). During this process, there is a point where volunteers cannot make
decisions anymore. Where is this point? During sedation we measured high
density EEG in 24 normal volunteers while performing an auditory go-nogo task
or a simple go-left/go-right task. We’ve characterized the dynamics of losing
the capacity to both, respond to the tones and, to make a decision during all
three transitions (sedation S0 to S1, S1 to S2 and S2 to S0). For the same
propofol concentration, some participants resisted the loss of consciousness
and continued to respond to tones, but RTs were delayed (from ≈ 500
to ≈ 2000ms); while the rest of the participants also showed
increased RTs but after a few minutes they stopped responding (unconscious
phase). We discuss here evoked related potentials of decision making during
these transitions and propose a model that may help to understand how we lose
and regain consciousness.
Martin Monti1 and
1 MRC
Cognition and Brain Sciences Unit martin.monti@mrc-cbu.cam.ac.uk
Disorders of consciousness such as coma, vegetative
state and minimally conscious state are among the most complex and least
understood conditions of the human brain. In particular, the assessment of
residual cognitive function, as well as awareness, is very challenging in
patients that have extremely limited (if any) capacity for motor output. Yet,
correct assessment of the level of preserved cognition and consciousness is
crucial for appropriate diagnosis, medical care and legal decision-making. With
misdiagnosis rates above 40%, novel methods are required to tease apart
vegetative and minimally conscious patients. Recent evidence has suggested that
functional neuroimaging may play a crucial role in correctly evaluating
cognitive capacity, as well as awareness, in brain injury survivors. In
particular, this technique, by directly observing brain metabolic response, dispenses
entirely with relying on the patients' motor capacity. For this tool to be
diagnostically relevant and clinically useful, however, it must be possible to
unambiguously distinguish automatic brain responses from willful mental effort.
To address this problem we present a series of functional magnetic resonance
imaging paradigms aimed at (i) assessing residual cognition and awareness in
non-behavioral brain injury survivors, and (ii) providing a channel for these
patients to communicate without relying on behavior. With respect to the first
point, we developed a hierarchical approach to testing several sensory
modalities, including vision and language processing, from basic sensory
perception to high-level processing, and willful brain modulation. With respect
to the second point, we show that, as demonstrated by a patient believed to be
vegetative for 5 years, it is possible to use willful brain activity as a
non-muscle dependent strategy to enable simple two-ways communication,
sufficient to answer a set of 'yes/no' questions.
(C)- Non-human consciousness and Dreaming
Chair:
Thomas Metzinger
Venue:
Giovanni Room (2nd Floor)
David Edelman1, Piero Amodio2, Anna Maria Grimaldi2,
and Graziano Fiorito2.
1 The
Neurosciences Institute david_edelman@nsi.edu
2
Stazione Zoologica Anton Dohrn
Over its relatively brief history, the scientific
study of consciousness has yielded some reliable neural correlates of conscious
states in humans. Moreover, a variety of
neuroanatomical, neurophysiological, and behavioral evidence is suggestive of
conscious states in some non-human animals.
However, confronting the question of consciousness in animals far
removed from the primate, mammalian, or even vertebrate lineages presents
serious methodological and theoretical issues, namely: 1) neural architectures that are poorly
characterized or radically different from those of vertebrates; 2) smaller
structural scales or other anatomical differences that require the development
of new surgical and recording techniques to acquire critical neurophysiological
data; and 3) establishment of benchmarks in well characterized animals that can
be used to formulate hypotheses to test in distant phyla, i.e., what conscious
states should ‘look like’ in such phyla.
The first two issues are methodological and will require significant,
albeit straightforward, effort to resolve.
The third issue, which is theoretical, can be addressed by starting from
the premise that there may be major functional properties common to all nervous
systems capable of conscious states.
Arguments based on rigid structural homology should therefore be avoided
in favor of those based on broad functional analogy. Accordingly, in invertebrate species, we must
identify neural structures that exhibit functions analogous to those of
vertebrate structures implicated in consciousness, as well as
neurophysiological signatures and behaviors resembling those observed in
conscious vertebrates. Endowed with the
most complex nervous system of any invertebrate and a sophisticated behavioral
repertoire to match, the octopus provides an excellent test case for conscious
states in animals well outside the vertebrate lineage. To explore aspects of visual perception and
sensory integration in the common octopus (Octopus vulgaris), we have performed
a variety of psychophysical experiments in which rapidly shifting sequences of
visual stimuli are presented, via video projection, at rates and durations
impossible to achieve through manual presentation. This methodology has allowed us to explore
perceptual properties that may be associated with awareness in these
animals. Here, we will discuss the
development of the methodology and present our latest findings. *Supported by the Neurosciences Research
Foundation.
M Alexis Garland1, Jason Low1, and Kevin Burns1.
1
Numerosity is one of a handful of fundamental
cognitive systems that create the framework for more complex cognitive
function. An approximate number system is described as underpinning human and
non-human animals’ representations of numbers greater than four, where
quantities of discrete objects are perceived on an approximated continuum of
subjective magnitude. According to Weber’s law, discrimination between two magnitudes
or sets is a function of their ratio rather than absolute number. This
mechanism is the key driver behind the approximate number system, and modulates
numerical discrimination ability in humans and a range of primates and other
species. It is widely believed that both human infants and animals cannot
discriminate large numbers without deploying a number system that obeys Weber’s
law. As a natural extension of number comparison, simple arithmetic
calculations such as addition and subtraction small numbers are a core feature
of numerical cognition, and consequently understood as equally effected by both
numerical size and distance. A series of experiments using paired number
comparisons, multiple-set chunking and addition and subtraction of artificially
cached items focused on examining large number perception in this songbird by
investigating visuospatial memory of hidden food caches containing small and
large numbers of mealworms (Tenebrio molitor), to construct an in-depth
understanding of numerical abilities in this avian species. These trials were
conducted within a wild population of the insectivorous food-hoarding New
Zealand Robin (Petroica australis), and demonstrate that this songbird displays
numerical discriminations independent of Weber’s Law and complex mathematical
reasoning, suggesting a shift from the established primate-centric signature
limitations that define both object and number perception. Robins’ unusually
sophisticated tracking of discrete number appears to be an evolutionary response
to the social and ecological challenges of their daily lives. Overall results
demonstrate that this scatter-hoarding songbird computes exact quantity
representations over small and large numbers.
Takaaki Kaneko1 and Masaki Tomonaga1.
1
Humans perceive an event that they cause
differently from other events that occur in their environment. Such unique
experiences, accompanied by our voluntary actions, are called the sense of
self-agency and allow us to establish the concept of self as being an
independent agent. Here, we investigated possible differences in the perception
of self-agency between humans and chimpanzees(Pan troglodytes), our
evolutionary closest neighbors. It is
known that chimpanzees have difficulties copying another individual’s motor
actions but they can reproduce the goal of the other’s action. These
differences may reflect variations in the perception of one’s own voluntary
actions. However, this issue has rarely been addressed from a
comparative–cognitive perspective. In this study, we show that chimpanzees had
monitored the goal of own action but was less attentive to one’s own kinematic
motion. In the experimental task, two
cursors were shown on a computer monitor, one of which was the distractor
cursor moved by the computer and the other was the self-cursor controlled by
the participant. The participants were required to detect the self-cursor, and
to hit either target shown on the monitor with that cursor. The chimpanzees spent more time detecting
the self-cursor when the target, that a chimpanzee was trying to hit, was
accidentally corresponded to the target which the distractor moved toward.
Meanwhile they required less time when the distractor moved toward different
targets. We did not observe such an effect in human participants. These results
indicate that chimpanzees were more dependent on the representation of goal
rather than kinematic motion for the self-other distinction and suggest a
discontinuity between humans and chimpanzees in the perception of
self-agency.
Alex Gamma.
ETH
Evolutionary Psychology (EP) is an ambitious
enterprise to explain the structure of the human mind based on
"evolutionary thinking". EP's basic idea is that the human mind consists
of specialized mental modules that evolved in our hunter-gatherer ancestors as
adaptations to their stone-age environments. Since (genetic) evolution operates
too slowly to have significantly changed these psychological adaptations,
modern man faces a particular predicament: while his mind is still largely
adapted to living conditions prevalent 100,000 years ago, modern environments
are so radically different from those ancient conditions that his mind will
often fail to produce adaptive behavior.
This explanation - while perhaps sometimes right - will often fail
because it is systematically incomplete. This follows from two extensive blind
spots in EP's theorizing: 1. EP
completely ignores development (ontogeny)
2. EP has a radically impoverished view of evolutionary inheritance,
and, a fortiori, of evolution itself.
1. Every trait of every organism develops. Individual development
(ontogeny) is a complex process of multiple interacting causes that jointly
determine both the bodily and the psychological traits of an organism. In
modern human beings, this process alone could be able to create a mental
architecture that adapts our behavior to our social and technological
environments - beyond any consideration of evolution. 2. Inheritance of traits is one of the
core mechanisms driving evolution by natural selection. However, nothing
requires inheritance to be exclusively a matter of the physical transfer of
genes. In fact, all that is required by "inheritance" in the
Darwinian sense is an increased resemblance between parents and offspring.
Thus, every causal factor internal and external to a child that makes it become
similar to its parents will subserve evolution by natural selection. Cultural
items that recur or are reconstructed in every generation meet the requirements
for being heritable resources just as well as genes do. And they are able to
affect the evolution of (e.g. mental) traits in fractions of the time needed by
purely genetic evolution. Therefore, human mental structure may generally be
much better adapted to current living conditions than EP would have us
believe.
The ‘primary consciousness’ entails the ability to
create a scene in the ‘remembered present’ (Edelman, G. M., 1989) in the
absence of language and may be a basic biological process in both humans and
animals lacking true language (Edelman, D. B. & Seth, 2009). The present
paper reports on an experiment investigating the possibility of existence of
primary consciousness in pill bugs. The antennae length of the subjects in the
test group was extended by using either short Teflon tubes (approx. as long as
the flagella of their own antenae) or with longer ones (approx. twice as long
as the flagella) attached to the tips of the antennae, while nothing was
attached to the individuals in the control group. They were each placed on the
top tier of 14 stairs, in which the depth between the first and the second
stairs was 5 mm, and the inter-step depth was increased by 1 mm for the rest of
the stairs. They were all highly motivated to move down the stairs to run away
from the experimenter. The maximum reachable stair and the body length for each
individual were recorded, and the correlation between the maximum reachable
stair and the tube length (none, short, and long) was calculated for each
body-length class (in the range of 9.8 to 11.2 mm). A significant positive
correlation was confirmed for the 11.2-mm body length class alone. This result
suggests that matured pill bugs that were 11.2 mm long might use the Teflon
tubes as tools to measure the inter-step depth with a ‘sensation at the tips of
invisible tools’ as human beings feel the touch at the tip of the tool, rather
than at the hand that holds the tool, when they touch something with a tool
(Yamamoto & Kitazawa, 2001).
Martin Dresler.
Max Planck Institute of Psychiatry dresler@mpipsykl.mpg.de
Since the discovery of the close association
between rapid eye movement (REM) sleep and dreaming, much effort has been
devoted to link physiological signatures of REM sleep to the contents of
associated dreams. Increased extrastriate and decreased prefrontal metabolism
in REM sleep have been suggested as correlates of vivid dream imagery and the
loss of volition in dreams. However, a direct demonstration of specific dream
contents by neuroimaging methods is lacking, also because predefined protocols
cannot be volitionally performed by the dreaming subject. By combining brain
imaging with polysomnography and exploiting the state of ‘lucid dreaming’ we
here show that a predefined motor task performed during dreaming elicits
neuronal activation in the motor cortex. In lucid dreams the subject is aware
that he is dreaming, with a wake-like access to memory, reflective thought and
volitional capabilities while all standard polysomnographic data of REM sleep
are fulfilled. Using eye signals as temporal markers, neural activity measured
by functional magnetic resonance imaging (fMRI) and optical topography (OT)
could be related to dreamed hand movements, while polysomnography verified that
subjects were in REM-sleep. The cortical activation pattern during dreamed
motor performance was highly similar to that during wakefulness. In summary, we
provided first evidence that the content of REM-associated dreaming can be
visualized by neuroimaging.
ASSC14 Conference Schedule
Sunday, June 27th
KEYNOTE 3 (
Venue:
Colony Ballroom (2nd Floor)
Varieties of Memory and Consciousness: A Cognitive Neuroscience
Perspective
Morris Moscovitch
The relation between memory and consciousness is
central to many theories of memory. In particular, conscious awareness is a
defining feature of memories that are explicit or declarative, and of one type
of declarative memory (e.g., episodic)
from another (e.g., semantic). I will question these views by drawing on
behavioural and neuroimaging data from intact and brain-damaged people to show
that there is more interaction than once was believed between these different
types of memory and the neural structures that mediate them, and that
consciousness may provide a clue about the nature of these interactions.
-- Coffee Break --
SYMPOSIUM 3 (
Crowding, blink and attention:
what can they tell us about Consciousness?
Chair: Ramakrishna Chakravarthi
Venue:
Colony Ballroom (2nd Floor)
Weak target masks and distant flankers interact to produce a
catastrophic supercrowding effect
Timothy Vickery
In the typical crowding experiment, flankers
degrade performance at identifying a peripheral object within a target-centered
window of approximately half of the target's distance from eye fixation. While
this “critical spacing” is not a strict limit, flankers rarely have a
substantial effect on performance outside of this range. However, when a barely
effective mask is applied only to the target item, flankers far outside of the
typical critical spacing range have a catastrophic effect on performance (up to
distances of at least 80% of the target's eccentricity). Further, while
crowding has not been observed at the fovea under typical paradigms, the
supercrowding paradigm consistently revealed interactions within at least 24
arcmin of a 16 arcmin stimulus. These findings suggest that seemingly
ineffective masks and flankers actually have a profound, seldom-measured effect
on perceptual mechanisms underlying identification.
The resolution of conscious vision: Visual crowding
in infants and adults.
David Whitney
Natural
visual scenes are cluttered. In such scenes, objects in the periphery can be
crowded – blocked from recognition and awareness – simply because of the dense
array of clutter. Outside the fovea, crowding constitutes the fundamental
limitation on conscious object recognition. Here, we present three findings on
the mechanism of crowding, the limits of crowding, and the development of
crowding. First, we show that crowding occurs at multiple, distinct stages of
visual processing, including selectively between high-level objects. Further,
we show that crowding does not dismantle or destroy object-level information;
an entire face can survive crowding and contribute its holistic attributes to
subsequent texture processing, despite being blocked from recognition. Finally,
we show the developmental trajectory of crowding from infancy; this reveals the
spatial resolution of conscious perception in infants. Together, our results
show that crowding is a dynamic and flexible process, modified with age and
operating independently at multiple stages.
Pool party: Admit one
Ramakrishna
Chakravarthi
CNRS,
Faculte de Medecine de Rangueil, Toulouse, France chakravarthi@cerco.ups-tlse.fr
Crowding is a result of inappropriate pooling of
target and flanker features. This pooling occurs over a very large area. It is
thought that everything within this area is combined. However, one very well
known exception is that flankers do not combine with the target unless they are
similar to each other. Here, we describe another important exception. Using
specially constructed stimuli, we show that flanker features interfere with the
target only if they are both close to the target and belong to
a unified object. Thus, the early visual system functions as a filter. It
continuously attempts to prevent features of extraneous objects from combining
with a target. When this fails, there is crowding. Our results are consistent
with the idea that a top-down, perhaps iterative, process selects what features
are pooled. This process constrains object representations, and ultimately what
we consciously see.
On when, how, and why attention blinks
Mark Nieuwenstein
While studies of selective attention examine how the human mind
enables the selection of a target stimulus from amongst distractors, studies of
divided attention examine the limits of attention by using tasks that involve
multiple target stimuli. These limitations of attention can be observed both
when multiple targets appear simultaneously in different locations (
-- Lunch Break --
SYMPOSIUM 4 (
Neurophysiological approaches
within the scientific study of consciousness
Chair: Alexander Maier
Venue:
Colony Ballroom (2nd Floor)
Backward masking and continuous flash suppression in human intracranial
recordings
Naotsugu
Tsuchiya
Intracranial recordings during
epilepsy monitoring offer valuable experimental situations, where we can record
direct neurophysiological responses from awake humans, with excellent
spatiotemporal resolution from many brain sites simultaneously. With such an
opportunity, we can investigate a specific hypothesis about the causal role of
long-range, large-scale neuronal activity in producing subjective conscious feelings
while subjects are performing a perceptual task (e.g., Varela, Dehaene). Here,
we report the results of intracranial recording studies using two
psychophysical techniques: backward masking and continuous flash suppression.
In both tasks, we used faces as target stimuli. While subjects performed the
tasks, we recorded intracranial EEG from 64-256 sites, including the primary
visual cortex, the fusiform gyrus, the superior temporal sulcus, the amygdala.
Applying a multivariate decoding techniques and Granger causality, we
characterize those processing which are correlated with conscious visibility
and those which are not available to consciousness, in terms of space
(anatomical areas), time, and frequency bands.
Activity in the primary
visual cortex related to visual awareness
Alexander Maier
National Institute of
Mental
Whether
or not activity in the primary visual cortex (V1) is related to the conscious
experience of a stimulus is a long-standing debate. To investigate existing
discrepancies in the literature, we measured the fMRI response, along with
electrophysiological signals, in V1 of trained monkeys, and correlated
responses there with the perceived visibility of a salient stimulus. We show
that stimulus visibility can be reliably derived from the fMRI signal, but not
from neural spiking activity. In contrast to the single neuron response, the
local field potential (LFP) underwent substantial modulation with changes in visibility.
LFP modulation was uneven between the cortical layers, thus hinting at
awareness-related activity changes within the V1 microcircuitry. We conclude
that stimulus visibility is represented in V1, but only minimally influences
the spiking rate of feature selective neurons.
Role of thalamo-cortical interactions in spatial awareness
Melanie Wilke
California
Institute of Technology,
Due
to devastating effects of lesions in the thalamus on conscious experience and
its strategic anatomical location, thalamo-cortical interactions have long been
hypothesized to play an important role in supporting consciousness (Edemann
& Tonoi, 1991, 2001; Crick & Koch, 1998). However, few studies have directly
investigated this hypothesis. Here we
studied thalamo-cortical activity related to visual consciousness by combining
behavioral measurements, electrophysiology, neuropharmacology and fMRI in
monkeys. We
first applied a paradigm which renders salient visual stimuli perceptually
invisible. Our neurophysiological recordings revealed widespread perceptual
modulation of local field potentials (LFP) in cortical areas V1, V2, V4 and the
thalamic LGN and pulvinar, accompanied by spiking rate changes in V4 and the
pulvinar. Comparison of V4 and pulvinar latencies suggest that perceptual
modulation of pulvinar neurons follows cortical input. Lastly, reversible
inactivation of the pulvinar resulted in awareness and action-related
behavioral deficits, and led to fMRI signal changes in cortical areas
associated with spatial awareness disorders in humans. Based on these results,
we conclude that a well coordinated thalamo-cortical interplay is a necessary
condition for creating and maintaining visual consciousness.
-- Coffee Break --
POSTER SESSION (
Titles and Abstracts listed after the final
talk sessions
Venue:
St Patrick & St David Rooms (3rd Floor)
--------------------------------
KEYNOTE 4 (
Venue:
Colony Ballroom (2nd Floor)
Oscillatory Dynamics in the Human Cortex
Robert T. Knight
Since
the discovery of the EEG in 1920’s, neurophysiological dogma for the ensuing 80
years stated that the human cortex did not generate reliable rhythms above
50-60 Hz. However, findings over the last decade report neural activity up to
250 Hz in the human cortex. This activity appears to be the key neural response
tracking cortical activation in humans. We record the human electrocorticogram
(ECoG) from subdural electrodes implanted in neurosurgical patients. We have
observed that every cognitive process examined including language, attention,
memory and motor control generates high frequency oscillatory activity in the
range of 70-250 Hz (high gamma, HG). Importantly, the HG band of the human ECoG
has the most precise spatial localization and task specificity of any frequency
observed. For instance, during linguistic processing, HG precisely tracks the
spatio-temporal evolution from comprehension in posterior temporal areas to
production structures in the left frontal region. HG a precisely tracks the
time course of the behavior needed to comprehend the word, select a noun and
articulate a response all occurring within a second. Similar findings of key HG
activity are observed for working memory, contextual processing and a host of
other human behaviors. Importantly the
HG response can be reliably extracted at the single trial level. HG is also
phase locked to the trough of theta rhythms in the human neocortex providing
parallel findings of HG-theta coupling in animal hippocampus and cortex.
HG-theta coupling occurs in a task specific manner with different cognitive tasks
eliciting unique distributed spatial patterns of HG-theta coupling. These results
indicate that transient coupling between low- and high-frequency brain rhythms
provide a mechanism for effective communication in distributed neural networks
engaged during cognitive processing in humans. Taken together the results
indicate that HG activity provides a powerful new tool for understanding the
real-time cortical dynamics subserving cognition in humans. The implications of
HG and inter-frequency dynamic to consciousness will be discussed.
Closing Remarks &
Presentation of Student Poster Prizes
Randy McIntosh & Mel Goodale
Venue:
Colony Ballroom (2nd Floor)
Poster
Session 1: Saturday, June 26th
Venue:
St Patrick & St David rooms (3rd Floor)
1.
Probing for functional sites of consciousness with
anesthetics: the role of the cytoskeleton.
Travis Craddock1,
Holly Freedman1, and Jack Tuszynski1.
1
While
much of the neurobiological approach to understanding consciousness focuses on
the level of the neuron, the nature of general anesthetics makes them a natural
molecular probe. Studies on the
mechanism of general anesthetic action tend to focus on the interaction of
anesthetic agents with subcellular structures, such as GABAa and NMDA
receptors, in the hopes of uncovering
functional sites of consciousness. In
recent years attention has been drawn to the cytoskeleton as a possible site of
anesthetic action and functional site of consciousness. The cytoskeleton is
essential to cell morphology, cargo trafficking, and cell division. The complex structure of the neuronal
cytoskeleton has been implicated to play a role in memory, and a startling
number of neurodevelopmental, neurological, and neuropsychiatric disorders show
a disordering in its function. However,
the role of the cytoskeleton in general anesthesia, and its link to
consciousness, remain questionable. To
investigate these possibilities we examine the interaction of volatile
anesthetics with cytoskeletal microtubules via computational modeling and
simulation. Results for putative binding
sites of anesthetics to microtubules, with the relation to overall cytoskeleton
function, are presented, providing insight on the role of the cytoskeleton in
anesthetic action and consciousness.
2. Monitoring the depth of
anesthesia using the time-varying spectral lines of EEG.
Eunji Kang1, Hossam El Beheiry2, Jean Wong1,
Peter Carlen1, and Berj Bardakjian1.
1 University of
2 University Health network
The
administration of the anesthetic agents is known to alter the
electroencephalogram (EEG) signal significantly as the brain being their primary
target. Thus incorporating some analysis of EEG in the assessment of the depth
of anesthesia (DoA) have been an active research area for many years. Although
there have been many promising results, their reliability and clinical utility
are still debatable. In this study, we analyzed the EEG recorded from six ASA
I/II patients undergoing 1-2 hour surgery. The EEG was collected before and
during induction, maintenance and recovery of anesthesia using the 10/20
lead-system. A combination of fentanyl and propofol (+/- rocuronium) was the
inducing agents and sevoflurane in air/O2 mixture was administered through an
endotracheal tube to achieve the steady minimum alveolar concentration (MAC) to
maintain haemodynamic responses during surgical stimulation within 25% of
baseline. The collected time series EEG signals were decomposed into the
time-frequency domain using the wavelet packet transformation. The power of the
EEG signal varied both in time and frequency as the DoA was varied. In fact,
there were a number of identifiable rhythms, some of which altered their peak
frequency with the change of DoA. These changes in the frequency of the rhythms
were tracked over time to produce the time-varying spectral line. The
time-varying spectral line adds another dimension to the currently available
monitoring techniques and it can improve the reliability and accuracy of the
monitoring of DoA.
3. Potential confounds in region of interest
studies of impaired states of consciousness.
David Jones1,
Brendon Boot1, Kirk Welker1, Jennifer E. Fugate1,
Daniel Drubach1, Alejandro Rabinstein1, and Eelco
Wijdicks1.
1 Mayo
Clinic jones.david@mayo.edu
Recently
published investigations of impaired states of consciousness have used region
of interest (ROI) functional magnetic imaging blood-oxygen level dependent
analysis techniques (fMRI BOLD). However the use of ROI’s preclude
investigation of global brain networks such as the default mode network (DMN).
Furthermore, using the BOLD signal from a single ROI (e.g. the supplementary
motor area, SMA) to identify changes during a task versus resting state is
potentially flawed: it does not account for neuronal and non-neuronal related
fluctuations in the BOLD signal that remains after bandpass filtering and standard
preprocessing steps. To illustrate this
point, we performed a comparable SMA ROI fMRI analysis on 10 healthy controls
resting comfortably in a 3T MRI scanner. Preprocessing steps included: slice
time correction, realignment, normalization (MNI space), smoothing (5 mm FWHM),
linear detrending, and high and low bandpass filtering (0.01-0.08 Hz). The
preprocessed data was then entered into a standard general linear model fMRI
analysis utilizing an SMA mask to define the ROI. The SMA ROI showed
considerable variability in the BOLD signal between subjects. One subject had
resting BOLD signal fluctuations that mirrored a potential 30 second motor
imagery task alternating with a 30 second rest block repeated for three cycles.
This produced a statistically significant activation with typical fMRI analysis
(p < 0.05, FDR corrected). This ROI based analysis identified task related
brain activity in the BOLD signal from the SMA of a subject who was not
performing any such task. Subsequent analysis of the entire brain revealed that
this activation pattern was artifactual in nature. This exploratory analysis, of spontaneous
fluctuations in the BOLD signal located within an ROI, highlights a potential
confound when attempting to find task related activation in large numbers of
subjects with impaired states of consciousness. Therefore, task-induced changes
in large scale networks, such as the DMN, should also be examined to verify
task specific BOLD changes. In addition, task-induced deactivations of the DMN
would provide compelling evidence for the interruption of a stream of
consciousness in subjects that clinically appear to have no stream of
consciousness.
4. Inverse
correlation of fMRI default mode network connectivity in the persistent vegetative
state.
David Jones1,
Brendon Boot1, Kirk Welker1, Jennifer E. Fugate1,
Daniel Drubach1, Alejandro Rabinstein1, and Eelco
Wijdicks1.
1 Mayo
Clinic bboot@med.usyd.edu.au
Functional magnetic resonance imaging (fMRI)
analysis techniques identify stable global brain networks termed intrinsic
connectivity networks (ICN). Changes in connectivity in one of these networks,
the default mode network (DMN), are associated with altered states of
consciousness (e.g. coma, persistent vegetative state (PVS), and minimally
conscious state). Studies suggest that there is a progressive decrease in DMN
connectivity as the level of consciousness declines. However, it is unclear
which connectivity factors serve as prognostic indicators. A 40 year old male
developed acute demyelinating encephalomyelitis and generalized
hypoxic-ischemic injury. He remained in a PVS for several months before and
during fMRI scanning. His clinical status was determined by two neurologists
specializing in neuro-intensive care prior to the scan and again several days
later when his level of consciousness had improved markedly. One month later he
follows with his eyes, says “Good Morning”, and follows some one-stage midline
commands. The patient and twelve age
and gender matched controls underwent a typical resting state fMRI scanning
session. Preprocessing steps included realignment, slice time correction,
normalization, smoothing, linearly detrending, bandpass filtering, and
correction for rigid body transformation motion effects, global mean signal,
white matter and CSF. Node to node functional connectivity analysis was
performed on a priori determined DMN seeds in the posterior cingulate (PCC) and
medial prefrontal cortex (MPFC). Voxel-wise connectivity analysis was performed
for each node and compared between groups using a two-sample t-test. The
voxel-wise connectivity analysis of the patient’s PCC seed showed a markedly
reduced spatial extent of the DMN compared to controls. In addition, seed-seed
analysis between the PCC and MPFC not only showed a lack of direct connectivity
in the patient, but also showed a striking inverse correlation between the two
nodes. This adds to the evidence that DMN activity may be useful in
investigations of consciousness. In addition, we report for the first time a
striking inverse correlation between the PCC and MPFC in a patient in a PVS who
subsequently improved in his level of consciousness. More investigation is
needed to determine whether PCC-MPFC inverse correlation is a sign of potential
recovery from a PVS.
5. Regional
thalamic atrophy in vegetative and minimally conscious states.
Davinia
Fernandez-Espejo1, Carme Junque1, Montserrat Bernabeu1,
Teresa Roig-Rovira1, Pere Vendrell1, and Jose Maria Mercader1.
1 University
of
The thalamus is known to play a key role in the
regulation of arousal and the support of human consciousness. Based on its
specific cytoarchitecture and anatomical specialization, it has been suggested
that the central thalamus could be supporting large-scale cerebral dynamics
associated with consciousness (Schiff, 2008). Neuropathological post-mortem
studies in traumatic brain injury (TBI) patients have suggested that, along
with widespread white matter damage, thalamic damage may be the basis of some
disorders of consciousness (Jennet et al., 2001). Here we present results from
our study that investigated thalamic regional atrophy in a sample of TBI patients
in vegetative (n=4) and minimally conscious (n=8) states using high-resolution
T1-weighted magnetic resonance images. We used the FIRST tool from FSL
(http://www.fmrib.ox.ac.uk/fsl/) to perform vertex-based shape analysis to
compare our patients group with 20 healthy control volunteers. Patients showed
a bilateral inward deformation in the thalamic dorso-medial bodies, in contrast
to partial preservation of other thalamic nuclei. These shape changes can be
explained by atrophy in the dorso-medial nucleus and the internal medullar
lamina. Our results confirm the
importance of central thalamic regions in supporting human consciousness.
Further, they suggest that specific damage to these areas might explain the
impairment of consciousness in severely brain damaged patients. References: Jennett, B.,
6. Language
comprehension in the vegetative and minimally conscious states.
Damian Cruse1,
Tristan Bekinschtein1, and
1 MRC
Cognition and Brain Sciences Unit damian.cruse@mrc-cbu.cam.ac.uk
The vegetative and minimally conscious states (VS;
MCS) are characterised by an inability to consistently demonstrate awareness of
self or environment. These diagnoses are
currently made on the bases of responses, or lack thereof, to verbal commands
to perform motor actions. It is becoming
increasingly clear, however, that a lack of control over motor behaviours is
not always accompanied by a lack of awareness on the part of the patient (Owen
et al., 2006, Science; Monti et al., 2010, New England Journal of
Medicine). While behavioural measures
may indicate a lack of understanding of spoken language, measures of neural
activity allow us to objectively determine the extent to which language
abilities may be retained by these patients who cannot make a motor
response. Functional magnetic resonance
imaging (fMRI) has previously demonstrated comparable brain responses in a
number of VS and MCS patients when listening to speech containing semantic
ambiguities (Coleman et al., 2007, Brain).
Crucially, this pattern of activity is not observed in fully sedated
individuals (Davis et al., 2007, PNAS) suggesting a level of conscious
awareness associated with this neural response.
Due to the expense, and exclusion criteria associated with fMRI studies,
however, the language comprehension abilities of a large number of VS and MCS
patients can never be determined with this method. The current study is focused, therefore, on
developing means of assessing language comprehension using the more portable
and inexpensive method of electroencephalography (EEG). The EEG provides a well-documented component,
the N400, which is tied to the semantic processing of linguistic stimuli. In the current study, verbal stimuli were
employed which varied along dimensions of semantic relatedness, and ambiguity
in the context of a sentence. A group of
healthy controls demonstrated the previously reported modulation of the N400
component along these dimensions.
Critically, however, this pattern was also observed in a number of
patients who were behaviourally in the VS or MCS. These results highlight the efficacy of EEG
in determining the extent to which language abilities are retained by these
patients, and also bring into question the behavioural criteria used to make
such diagnoses.
7. Is
anybody in there? Detecting consciousness
without language comprehension or behavioural responses.
Ryan Scott1, Ludovico Minati1, Anil Seth1,
and Zoltan Dienes1.
1
University of
The assessment of consciousness in brain injured
patients is essential for the differential diagnosis of vegetative state,
minimally conscious state, and locked-in syndrome. Accurate diagnosis has
important implications for prognosis, clinical management, and planning of
long-term care and rehabilitation [1]. Current clinical practice relies heavily
on behavioural evaluation and is therefore limited where either volitional
motor responses or language comprehension are compromised [2]. These
limitations contribute to rates of misdiagnosis, currently estimated at 37-43%
in patients diagnosed as vegetative state [3,4]. A novel learning-based procedure is proposed
to overcome these limitations. We demonstrate a situation where only
consciously detected violations of an expectation lead to changes in galvanic
skin resistance (GSR). Thirty healthy volunteers listened to sequences of 3
piano notes that, without their being told, predicted either a pleasant fanfare
or an aversive white noise according to a simple rule. Stimuli were presented
either without distraction (attended condition) or while distracted by a visual
task to simulate the absence of conscious awareness (unattended condition). A 5
min training phase preceded a 20 min test-phase that included violations of the
rule – the white noise occasionally following a note pattern that would
otherwise have predicted the fanfare. All
participants in the attended condition and none in the unattended condition
reported awareness of the rule and its subsequent violation. Thus, learning
occurred without instruction and was reliant on conscious attention. Six
participants did not show a robust sympathetic response to the white noise and
were hence excluded from assessment. In the remaining participants (12 in each
condition), GSR was contrasted for the white noise on trials violating the rule
and trials conforming to the rule. Learning should be apparent as greater GSR
when the rule is violated, making the noise unexpected. In the attended
condition this difference was significant for 11 participants (p<0.05) and
marginal for 1 (p=.071). In the unattended condition the difference was not
significant for any participant (all p>.13). Thus, learning was detectable
from GSR differences. This procedure may for the first time permit clinical
assessment of conscious awareness that is neither reliant on language
comprehension nor behavioural responses.
8. An fMRI study of the default mode network
connectivity in comatose patients.
Loretta Norton1, Matt Hutchison1, Michael Sharpe1,
1 University
of Western
Introduction:
Functional connectivity within a resting state network, termed the default mode
network (DMN), has been suggested to represent the neural correlate of the
stream of consciousness. Areas encompassing the DMN include the posterior
cingulate cortex/precuneus, the medial prefrontal cortex, and bilateral
temporoparietal junctions. Altered states of consciousness where awareness is
thought to be absent could provide insight into the function of the DMN. Here
we examine the functional connectivity in the DMN in both reversible and
irreversible coma. Methods: Twelve healthy control subjects (age: 28.4 ± 4.2)
and thirteen comatose patients following cardiac arrest (age: 64.6 ± 10.1, 2
patients with reversible coma) were included in the study. Along with the
clinical assessment, Glasgow Coma Scale ≤8 was used an indicator of
coma. The functional MRI scans acquired 118 volumes at 1.5T. Independent
component analysis (
9. Default
mode network and impaired consciousness in epilepsy.
Hal Blumenfeld.
Neurology, Neurobiology and Neurosurgery, Yale
University School of Medicine hal.blumenfeld@yale.edu
The “default mode” network, consisting of medial
parietal along with medial frontal and lateral parietal cortex, is thought to
participate in normal conscious introspection and unstructured rumination. Reduced activity has been observed in these
regions when subjects engage in tasks, leading to the hypothesis that
suspension of default mode activity occurs when subjects interact with the
external world. Using a combination of
neuroimaging and electrophysiological methods, we recently found that reduced
default mode network activity also occurs in three specific seizure types
associated with impaired consciousness.
In contrast to normal conditions, during these seizures there is reduced
default mode activity while subjects are completely unable to interact with the
external world. We found that rather
than passive suspension of normal activity, seizure mechanisms actively reduce
activity in default mode networks.
1. Using functional magnetic
resonance imaging (fMRI) during childhood absence seizures, we observed that
early abnormal increases in activity precede massive abnormal fMRI decreases in
default mode networks during seizures.
This pattern suggests that the observed decreases could represent an
undershoot phenomenon of neuronal recovery following abnormal activation. 2.
During generalized tonic-clonic seizures we found that decreased
cerebral blood flow in default mode networks measured by single photon computed
tomography (SPECT) was strongly correlated with cerebellar increases during and
following seizures. Because the
cerebellum consists largely of inhibitory Purkinje cells, and cerebellar
activity was also found to correlate with the thalamus, these findings suggest
that default mode decreases in tonic-clonic seizures are caused by active
cerebellar inhibition of thalamocortical networks. 3.
Through investigation of temporal lobe seizures in both human patients and
animal models we found reduced cerebral blood flow and increased cortical slow
oscillations in default mode regions, associated with abnormal activity in
subcortical arousal systems. These
findings support a “network inhibition hypothesis” by which active inhibition
of subcortical arousal systems during limbic seizures causes cortical
inactivation resembling coma or deep sleep.
In summary, converging evidence from different seizure types shows
abnormally decreased activity in default mode networks during epileptic
unconsciousness. Further investigation
may elucidate the role of default mode networks in both normal and impaired
consciousness.
10. Sleep
patterns and their significance for disorders of consciousness.
Manuel Schabus1,
Kerstin Hoedlmoser1, Katharina Weilhart1, Christoph
Pelikan1, Nicole Chwala1, Victor Cologan1,
1
University of
INTRODUCTION:
The sleep-wake system and consciousness are intimately connected. Therefore, a
better characterization of sleep timing and architecture in patients suffering
from clinical disorders of consciousness (DOC) might improve our understanding
of neural correlates of consciousness. Consciousness consists of two
components: arousal (wakefulness or level of consciousness) and awareness
(content of consciousness). Previous studies in DOC have reported a wide
spectrum of sleep disturbances ranging from almost normal patterns to severe
loss and architecture disorganization. Furthermore it appears that the very
existence of sleep is a challenging issue as these patients do not show the
normal behavioural, physiological and regulatory signs of sleep. METHOD: Up to now we performed 24h polysomnographies
in 28 patients being either in a vegetative (VS), or minimally conscious state
(MCS) following a traumatic or non-traumatic brain injury. Coma state was
classified using the Coma Recovery Scale-Revised (CRS-R). RESULTS/DISCUSSION: Cortical
desynchronization arousals appeared to be the best marker for VS patients who
showed later progression. Spindles on the other hand appeared predictive for
emergence out of MCS. However, more patients are needed in order to evaluate
the clinical value of the various sleep features.
11. Higher
order thoughts and hypnotisability.
Rebecca
Semmens-Wheeler1 and Zoltan Dienes1.
1
University of
The mechanisms underlying hypnotic susceptibility
have remained elusive despite decades of research. The cold control theory of
Dienes and Perner (2007)posits that inaccurate higher order thoughts (HOTs)
about first order intentions may be responsible for the cardinal experience of
involuntariness in hypnosis. Thus, individual differences in hypnotisability
may be related to a person’s habitual awareness and control of their mental
states. Participants of high and low hypnotic susceptibility (‘highs’ and
‘lows’, respectively) performed a task designed to measure the relation between
higher order thoughts and first order states (the “candle task”), and also
completed a number of self-report measures concerning control and awareness of
mental states and the world. In the
candle task, participants were required to cultivate or avoid thoughts of a
candle while looking directly at it. There was a trend for highs to have fewer
candle related HOTS (weaker ‘HOT coupling’) and they showed less meta-awareness
during the task, suggesting that highs are poorer at forming accurate
HOTs. The self-report measures completed
were: mindfulness (present awareness of the world), thought control, thought
suppression, cognitive failures, internal-external encoding, and absorption.
Highs scored significantly higher on measures of cognitive failures, thought
control, absorption and thought suppression than lows did, and their scores on
the mindfulness scale were significantly lower. Significant positive
correlations were seen among hypnotisability, cognitive failures, thought
control, absorption, thought suppression, and internal encoding. All these
measures correlated negatively with mindfulness and meta-awareness on the
candle task. Hypnotic responding may be related to greater attempts to control thoughts,
leading to reduced (externally directed) mindfulness and increased cognitive
failures, together with increased absorption. The greater attempts at control
of mental states go with a reduced awareness of mental states, and it is the
latter that is responsible for the hypnotic experience.
12. Conceptual
requirements for state consciousness: HOT theory, autism, and a minimally
sufficient TOM.
Lee-Anna
Sangster.
The
This paper brings
together Philosophical theory and empirical evidence from Developmental
Psychology to investigate the requirements for having conscious states of
mind. Specifically, according to
Rosenthal’s Higher-Order Thought Theory of Consciousness, mental states become
conscious if and only if they become the objects of higher-order thoughts
(HOTs) and one requirement of forming such HOTs is that an individual have some
way of conceptualizing the first-order states of her own mind. The exact level of conceptual sophistication
required, however, is a point that remains unclear. While some have tried to gain traction on
this issue by looking at theory of mind development in normally developing
young children, I suggest that it may be more informative to look to the
clinical population of people with Autism Spectrum Disorders (ASDs) instead,
because many people with ASDs, despite demonstrating relative cognitive
competency in other areas, seem to have a strikingly specific inability to
understand the mind. If it can be shown
that they have conscious states but do not have the requisite abilities to form
HOTs, people with ASDs may be a counterexample to Rosenthal’s theory. If, on the other hand, it can be shown that
they have some minimally sufficient conception of the mind, this fact could
shed light on questions arising both for Rosenthal’s philosophical account of
consciousness as well as for the empirical study of the development of a theory
of mind. Thus the first part of the
paper identifies some potential measures of an individual’s possession of a
minimally sufficient conception of the mind.
The second part of the paper looks to the empirical research to see
whether people with ASDs show evidence of having these abilities. Finally, the third part of the paper raises
some new theoretical and empirical questions, which arise from the discovery
that people with ASDs seem able to reason about desires despite showing no
indication of understanding the representational nature of the mind.
13. Detecting
movement volition in a patient with vegetative state.
Haibo Di1,
Zirui Huang2, and Steven Laureys1.
1
2
Institute of Psychology, Chinese
Recent functional neuroimaging paradigm can
unequivocally demonstrate a level of preserved conscious awareness in patients
meeting the clinical criteria for vegetative state, using tasks that tap
“volitional” aspects of behavior (Owen et al., 2006). However, this volition
paradigm, that requires patients to process mental imagery, is hard to perform
for patients in such a difficult state (Monti et al., 2010 ). We conducted an
fMRI study using a Hand Moving task in 12 patients with VS and one with MCS.
During the scan, the patients were given spoken instructions to perform a task
that required them to raise hand at specific time points. Only one of the 13
patients, who fulfilled the criteria for vegetative state by clinical CRS-R
assessment, was observed significant activity in the supplementary motor cortex
(SMA), primary motor cortex (M1), anterior cingulated cortex (ACC) and
cerebellum during the “Hand Moving” period. Her neural responses were
indistinguishable from those observed in 15-healthy volunteers performing the
same tasks. The results confirm that, despite fulfilling the clinical criteria
for a diagnosis of vegetative state, this patient retained the ability to
understand instructions and to voluntarily perform the task through her brain
activity, rather than through speech or actual movement. Our approach permits an easier and more
direct way to assess whether behaviorally diagnosed patients in VS are truly
conscious or not, and to further avoid diagnostic errors. Our paradigm seems
more propitious to apply and popularize in clinical situations as a
supplementary tool to diagnose some patients who are aware but unable to
produce an overt motor output.
14. Consciousness
at stake: perceptual and semantic decisions under sedation.
Ram Adapa1,
Tristan Bekinschtein1, Anthony Absalom1,
1 Division
of Anaesthesia,
Auditory processing is susceptible to alterations
in the level of consciousness. We used propofol (an anaesthetic agent acting
mostly via the GABA-A receptor) to reversibly manipulate the level of
consciousness in order to detect the neural correlates of semantic processing
during sedation. Propofol administration was titrated to three plasma levels,
and we tested perceptual and semantic processing at: baseline (S0, targeted
plasma concentration: 0µg/ml), low (S1, targeted plasma concentration: 0.6
µg/ml) and moderate (S2, targeted plasma concentration: 1.2 µg/ml) levels of
sedation. Participants were fully conscious at baseline, in a relaxed state
(able to maintain a conversation with ease) at the lower level of sedation, and
were drowsy (able to maintain a conversation only with difficulty) at the
moderate level of sedation. 24 subjects decided whether the auditory stimuli
presented was a noise or a buzz (perceptual decision), or a living or
non-living entity (semantic decision) in all sedation levels and while
connected to a high density EEG. Perceptual decisions were faster than semantic
decisions in all sedation levels. The higher the sedation level the slower the
responses for both conditions. In sedation level S2 reaction times were delayed
(from approximately 700ms to 2500ms) and participants showed more errors in the
semantic than in the perceptual decision condition. We discuss here the evoked
related potentials of the perceptual and semantic decisions during these
conditions and differentiate the neural correlates between concrete and
abstract decisions in different levels of consciousness.
15. Out-of-body
experiences – is there need for a composite hypothesis?
Marco A. Benz.
During out-of-body experiences (OBEs) the unity of
self and body appears to be disrupted, and the experiencing subject may
perceive the world, and sometimes his or her own body, from a distant
visuo-spatial perspective. OBEs are commonly reported by patients suffering
from focal epilepsy or other localized pathologies affecting the cortex at the
temporo-parietal junction (TPJ). Additionally, OBEs have been induced
experimentally in humans by electrical stimulation at the (right) TPJ. Based on
these observations it was hypothesized by Blanke and others that OBEs may
result from a disintegration of multimodal body-related information at the TPJ.
Notably, OBEs are also reported in the absence of any evident pathology: they
may occur spontaneously, as a component of near-death experiences or lucid
dreams, and can also be induced voluntarily using appropriate mental
techniques. The “disintegration hypothesis” is very plausible for OBEs
resulting from pathological neuronal information processing; however, at first
glance, its implication for cases of OBEs arising in the absence of evident
pathology seems less obvious. In these cases, the “dissociation model of OBEs”
put forward by Irwin seems a promising account. Also, if the concepts of
disintegration and dissociation overlap, I argue that both approaches need to
be considered for an in depth understanding of OBEs. However, since the
“dissociation model” is a psychological hypothesis it needs to be translated
into a physiological-functional model in order to be integrated with the
dissociation model. To this end, I consider the concepts of “top-down” vs “
bottom-up” neuronal processing to be useful. A “composite hypothesis”
(disintegration and dissociation) may provide a better understanding of shared
phenomenological aspects of OBEs as well as of more individual neurovirtual
experiences during and after OBEs.
16. Self-regulation in children
with ADHD: Behavioral and fMRI data.
Hélène Poissant1,
Adrianna Mendrek2, Noureddine Senhadji1, Bianca Bier1,
and Gilles Raiche1.
1 Universite Quebec Montreal poissant.helene@uqam.ca
2 Universite de
Self-regulation refers to the active evaluation of
the cognitive processes implicated in
goal-directed behavior. A dysfunction of the ventromedial prefrontal and
anterior cingulate cortices, which affects executive function, could partly
account for the problems observed in the ADHD.
These regions are implicated in inhibition, attention, planning and
regulation. Objective: 1) Determine
brain activations in children placed in a situation of self-regulation. Method: Forty-eight right-handed children
(20 ADHD and 28 CONT) performed the task consisting of identifying the
incoherent (INC) items among 56 pictorial stories presented in a block-design
manner during two runs of fMRI.
Results: Behavioral data showed difference between the groups in term of
the error rate but no reaction time (RT) nor interaction. Time-per-target
showed a significant interaction (ADHD are slower vs. CONT and faster in INC vs. CO). The fMRI analysis of the
INC-COH contrast revealed activations in the dorsolateral prefrontal (DLPF)
cortex in the ADHD group and orbitofrontal and anterior cingulate cortex (AAC)
in the controls. There were additional
activations in the temporal and parietal cortices in the ADHD children. The results imply that children with ADHD
recruit different neural circuitry to arrive at a performance similar to
healthy children on the self-regulation task.
17. Prefrontal
activation in performing on computerized maze problems: how cognitive
consciousness works. Hiromitsu Miyata1, Shigeru Watanabe2,
Yasuyo Minagawa-Kawai1.
1
2 Keio
University
Planning, the internal processes of formulating an
organized method about ones’ future behavior, seems to form a crucial part of
cognitive consciousness for both humans and non-human animals. The present
study using near-infrared spectroscopy (NIRS) examined prefrontal activation
associated with maze-solving performance in human adults. The participants were
required to solve two maze tasks, comparable to the ones used for both pigeons
and human children to behaviorally assess their planning processes, by moving a
target square to a goal square presented on a touch-sensitive screen with their
fingers. In Experiment 1, we used a plus-shaped maze and in some trials the
goal jumped to the end of another arm when the target arrived at the center of
the maze. The participants frequently made incorrect responses toward a
previous goal, similarly to pigeons and human children but less frequently than
these subjects, with shorter reaction times than when they correctly adjusted
their responses. In these incorrect trials relatively larger hemodynamic
changes having two peaks were observed, especially in channels of the right
hemisphere, suggesting use of additional cognitive resources for adjustment of
responses after making errors. In Experiment 2, we used a variation of the
plus-shaped maze that had eight arms (i.e., a shuriken-shaped maze) and
presented the maze for 10 seconds before the participants were allowed to solve
them. In some trials the goal jumped to another end of the arm immediately
after the color of the maze changed from the preview to the solution phase. In
these goal-change trials the participants moved the target toward correct
directions in almost all trials. In these trials as well as in baseline trials,
two-peak waveforms were observed with the first peak during the preview phase
and the second peak during the solution phase. The two-peak waveforms observed
in both of these experiments seem to suggest that cognitive consciousness that
was once activated for task solution/preparation can undergo an additional,
even larger activation when some additional event occurs during the course of
task solution. Also, similarity of the behavioral results across species may
suggest an evolutionary convergence of such processes.
18. Practical
measures of integrated information for stationary, continuous systems.
Adam Barrett1 and Anil Seth1.
1 Sackler
Centre for Consciousness Science,
Integrated information theory (IIT) has recently
gained prominence as a theory of consciousness. IIT posits that any physical
system has the potential to generate consciousness, and that the quantity of
consciousness present corresponds to the integrated information generated [1].
Integrated information, PHI, is computed by quantifying the extent to which the
system as a whole generates more information than the sum of its parts.
However, in its present form [1], PHI cannot be measured for real neural systems,
undermining its scientific utility. We
present a new measure of integrated information, stationary PHI (SPHI), which
is measurable for real neural systems. Defined for any system whose states are
statistically stationary, SPHI measures information as reduction in uncertainty
from the stationary distribution. By contrast, the formulation in Ref. [1] takes information as reduction in
uncertainty from the maximum entropy distribution. Use of the stationary distribution, instead
of the maximum entropy distribution, gives rise to two key features that enable
SPHI to be measurable from time-series data. First, it is well-defined for
systems whose states may vary continuously. Second, it can be measured purely
through observation, without recourse to perturbation of system subsets. When
states are Gaussian distributed, SPHI can be computed directly from empirical
covariance matrices, and can in fact be expressed in terms of linear
regressions, which further enhances its practical application. The latter
property also motivates a second measure, ARPHI (autoregressive PHI), defined
directly from regression errors. ARPHI is equivalent to SPHI for Gaussian
systems, whereas for non-Gaussian systems it provides a pragmatic alternative
to SPHI. ARPHI (and SPHI for Gaussian
systems) are state-independent. Therefore, to the extent that they are
considered as measures of consciousness, they predict that (i) conscious level
is constant during each stationary epoch in brain activity, and (ii) conscious
level changes when functional connectivity changes, modifying the stationary
statistics. To better understand the relations between structural connectivity,
functional connectivity and integrated information, we present results from
optimizing SPHI across a variety of simulation models, as well as comparisons
with related measures such as ‘causal density’ and ‘neural complexity’. [1] Balduzzi, Tononi 2008.
19. Relating
metacognitive sensitivity to human brain structure: a combined
psychophysical-MRI study.
Stephen Fleming1,
Rimona Weil1, Raymond Dolan1, and Geraint Rees1.
1
University College London s.fleming@fil.ion.ucl.ac.uk
Humans have the ability to relate decision
performance to awareness, but the neural basis for this ability remains
unclear. Such reflective judgments of confidence or certainty may differ from
objective performance. For example, a task can be performed poorly, yet the
individual may believe his or her performance was good, or vice-versa. Metacognitive
sensitivity has been proposed to underpin fundamental aspects of human
consciousness (Lau, 2008; Rosenthal, 2000).
We investigated this introspective mapping by using signal detection
theory (Type II SDT) where high confidence correct judgments were assigned as
introspective “hits”, and high confidence incorrect judgments as “false alarms”
(Kunimoto et al., 2001). We related SDT measures of metacognitive sensitivity
for a simple psychophysical task to brain anatomy. A psychophysical staircase
procedure coupled with post-decision confidence ratings was used to
characterize inter-individual differences in a Type II ROC-based metacognitive
measure (Aroc) in 31 healthy participants. All participants also underwent
high-resolution anatomical and diffusion-weighted MRI scans. Substantial
variation in Aroc was observed despite constant objective performance (d’).
Variation in metacognitive sensitivity (Aroc) correlated with gray matter
volume in frontopolar cortex (BA10; P < 0.05, whole-brain corrected) and posterior
cingulate/precuneus (P < 0.001, uncorrected). In addition, white matter
connectivity as indexed by fractional anisotropy (FA) was seen to be greater in
the anterior corpus callosum (connecting opposite regions of prefrontal cortex)
in high Aroc individuals. Together our results indicate a striking dependence
of metacognitive sensitivity on underlying brain structure.
20. An anatomical prerequisite of consciousness: Convergent -
divergent transmission nets.
Thomy Nilsson.
Department of Psychology,
Geometry presents a seemingly impassable
information bottleneck to justify brains larger than those of
invertebrates. A brain's aperture
surface limits how many neural pathways from the larger surrounding body can be
connected. Since speed is as vital as
precision, and conduction speed is proportional to fiber diameter; connecting
pathways cannot be shrunk to squeeze more through the aperture. The problem increases as larger bodies
involve longer transmission distances. A
similar constraint on output pathways limits a brain's ability to control the
surrounding body. A solution accompanied
the arrival of vertebrates, making possible larger brains and bodies. Its nature was revealed in experiments on the
organization of sensory pathways in the rabbit ear by Weddell, Taylor &
Williams (1955). To map these pathways,
they counted the number of hair-cell receptors in a certain area and the number
of dendrites from that area. There were
about 20X as many receptors as exiting dendrites. (Fortunate. otherwise there would be little
room left in the rabbit brain.)
Exquisite tactile localization ruled out simple summation. Further examination found that each hair-cell
connected to more than one dendrite.
Weddell, et al concluded that this convergent-divergent neural
organization somehow maintained acuity.
It has become recognized that most sensory systems are
convergent-divergent, but how remained a mystery. To explain convergent-divergent sensory
systems, I built some neural models.
There was only one basic branching pattern that could transmit
information from many inputs along a fractional number of pathways without
losing acuity (Nilsson, 2008). A
two-dimensional sensory array is limited to a 16-1 convergence - roughly what
Weddell, et al found. Transmission of
information within a brain faces similar geometric constraints since the
surface of any region is proportional to its linear dimensions squared, but its
volume is proportional to their cube.
The problem worsens for larger brains because transmission delays must
be reduced by larger fibers. Though not
yet mapped within a vertebrate brain, convergent-divergent organization of
intracortical pathways seems essential.
Jerison's (1973) theory of consciousness requires a confluence of
information from various senses. Only a
convergent-divergent organization makes this possible.
21. Human
brain connectivity subserves the conscious condition.
Imperial College London m.shanahan@imperial.ac.uk
In consciously-mediated behaviour, in contrast to
automaticity, a significant subset of the resources of a person’s brain can be
brought to bear on the ongoing situation, including working memory processes
and episodic memory processes as well as specialised motor processes. According
to the present paper, this is made possible thanks to a connective
infrastructure that allows the influence of individual brain processes to
permeate the whole system while the system as a whole can influence individual
brain processes. Under these conditions, the activity of massively many
parallel processes can be orchestrated, creating unity out of multiplicity. Support for this idea comes from the
growing body of evidence that human brain structural and functional
connectivity forms a modular, small-world network with a pronounced connective
core (Hagmann, et al., 2009). Such a network supports a dynamical milieu that 1)
is characterised by episodes of broadcast punctuated with bursts of
competition, which is the dynamical signature of a global neuronal workspace
(Shanahan, 2008a; Doesburg, et al., 2009), and 2) promotes dynamical complexity
(a balance of integrated and segregated activity), which facilitates an
open-ended repertoire of coalitions of brain processes (Shanahan, 2008b;
2010a). Doesburg, S.M., Green, J.J.,
McDonald, J.J. & Ward, L.M. (2009). Rhythms of Consciousness: Binocular
Rivalry Reveals Large-Scale Oscillatory Network Dynamics Mediating Visual
Attention. PLoS ONE 4 (7), e6142.
Hagmann, P., Cammoun, L.,
Gigandet, X., Meuli, R., Honey, C.J., Wedeen, C.J. & Sporns, O. (2008).
Mapping the Structural Core of Human Cerebral Cortex. PLoS Biology 6 (7), e159. Shanahan, M.P. (2008a). A Spiking Neuron
Model of Cortical Broadcast and Competition. Consciousness and Cognition 17,
288–303. Shanahan, M.P. (2008b).
Dynamical Complexity in Small-World Networks of Spiking Neurons. Physical
Review E 78, 041924. Shanahan, M.P.
(2010a). Metastable Chimera States in Community-Structured Oscillator Networks.
Chaos 20 (1). Shanahan, M.P (2010b).
Embodiment and the Inner Life: Cogition and Consciousness in the Space of
Possible Minds.
22. A model of primitive consciousness on an autonomously
adaptive system.
Yasuo Kinouchi1, Shoji Inabayashi2, and Yoichi
Nakazaki3.
1, 3 Tokyo
University of Information Sciences kinouchi@rsch.tuis.ac.jp
2
Pacific Technos Corp.
A
model of primitive consciousness is proposed through investigation of a system
that autonomously adapts, without a teacher, to its environment. This system is
required not only to respond to the environment as fast as possible but also to
provide a response of a quality that is appropriate to the situation based on
its previous experiences. The system should grasp the situation, decide the
action appropriately, and adapt by modifying its own configuration on the basis
of its experience. To do these things as a single entity, the system has one
evaluation mechanism, that is based on rewards or punishments. First, a main part of consciousness is
modeled as a function to do an appropriate speedy action. For this, the system
should quickly calculate a draft of a desired action based on a large amount of
information, such as the results of recognition from sensory processing,
recollections from the episodic memory, and states of the system itself. This
calculation is done with neural loops, in which information is represented as a
random pulse ratio. Each node relates to an imagery concept. Connections
between nodes correspond to relations between imagery concepts. Each loop
represents constraint conditions or equations. These loops operate as a solver
that uses the iterative method of nonlinear simultaneous equations. The pattern
of exciting nodes represents drafts of action at that time. The concept of
"functional consciousness", including Baars's global workspace
theory, is explained by using the above
function. Second, to allow the system to
control itself efficiently, only information needed to control the system is
selected. The information selected, such as available alternatives or action
space with relation to rewards and punishments, make up a compact space that
corresponds to the everyday world that we feel consciously. Additionally, the
pair of the solver of simultaneous equations and the evaluation mechanism
functions as a "self" of the system, and this self approximately corresponds
to Koch’s non-conscious homunculus. "Phenomenal consciousness" is
simply modeled by using the compact space and the self.
23. The
network properties of conscious experience: 'small worlds' and functional
connectivity.
Erik Hoel1,
Michael Hogan1, and Jane Couperus1.
1
Some consciousness researchers have hypothesized
that "explanatory correlations" may hold between brain activity and
subjectivity (Seth, 2009). For example, functional integration and
differentiation within brain activity may account for the unity of
consciousness and the extremely large number of possible conscious states,
respectively (Tononi & Edelman, 2000). Graph theoretical measures that reflect
these properties in whole-brain activity have been developed, and using these
measures recent medical studies have found significant abnormalities in
populations suffering from Alzheimer's disease (de Haan et al., 2009) and
schizophrenia (Micheloyannis et al., 2006). However, few studies have looked
for within-subject task effects using graph theoretical analysis, and none have
used this analysis to investigate basic questions of consciousness research.
Using synchronization likelihood (Stam, 2002) as a measure of electrode
coupling in 64 channel EEG, we extracted functional brain networks to seek
explanatory correlates of consciousness. Emulating Hakwan Lau's 2006 fMRI
study, we induced relative blindsight in participants undergoing EEG recording.
Relative blindsight was achieved when participants performed a task in which
behavioral performance was matched between identical conditions but
self-reported level of stimulus awareness differed significantly. Participants
also performed a complementary working memory task in which they viewed
identical stimuli while task difficulty was varied. This allowed us to
disentangle and separately investigate functional and phenomenal views of
consciousness. We assess mean path length (integration), coupling coefficient (differentiation),
and 'small-worldness' (an optimal balance between path length and coupling
coefficient; see Watts & Strogatz, 1998) between conditions and compare
differences between tasks. Preliminary analysis shows that in the working
memory task, task difficulty correlates with lower path length and higher
'small world' value, whereas in the relative blindsight task a higher level of
perceptual consciousness correlates with higher path length and coupling
coefficients and lower 'small world' value.
24. EEG
validation of a proposed regulatory definition of phenomenal experience.
Sarah Borrett1,
Mohamed Abdelghani1, Pushan Lele1, Don Borrett1,
and Hon Kwan1.
1 Department
of Physiology, University of
Contemporary consciousness studies tend to give
priority to the present in any analysis of the neural basis of conscious
experience, a bias that does not correlate with our own phenomenal experience.
The fundamental form that our phenomenal experience takes can be characterized
as a " presence in absence", in which the present sensible experience
acquires its significance through what is absent, the temporal horizons that
frame or envelop the present. A regulative definition of phenomenal experience
in a physical system is proposed based on this form that gives weighting to the
past and future; a necessary condition
for the present sensory state of a physical system to be experienced
phenomenally is if the present sensory state can be related to the system's own
time horizons. These time horizons are identified with the time scales that are
recordable in the system's dynamic.
Phenomenal experience corresponds to the present sensory state of a
system framed by the time scales to which the system has access. We recorded the EEG in subjects performing
two identical sensory-motor tasks that involved
manual tracking of a target cursor on a computer screen with a joystick.
In the first trial the pattern was predictable whereas during the second the pattern
was random. Even though the sensory input and motor output were the same in the
two conditions, changes were seen in the distribution of time scales in the EEG
signals with the predictable pattern having a scale free distribution and the
random pattern a bimodal or two peaked distribution. These distributions
correspond to our phenomenal experience of a lack of subject object distinction
with skilful coping (predictable pattern) and a phenomenal experience of a
separation of subject and object during breakdown (random pattern). Since
phenomenological accuracy is maintained with this proposed regulative
definition, it deserves further study in establishing the physical basis of
phenomenal experience.
25. Magnetoencephalography
(MEG) in Sudoku-puzzle solving task.
Yoshi Tamori1
and Kensuke Tsuda1.
1
Creative thinking is the great gift for every
human-being, which is surely under the control of the brain. Thus creativity is
one of the brain functions. Creativity is related to wide-spread domain in the
human culture such as academic field, art, literature, and so on. The common
attributes of creativity are involvements to the solution, generative thinking,
diversified thinking, and sudden-insight. It is expected that creativity is
implemented by the brain activities related to such factors. To examine the
creative brain functions, Sudoku-puzzle solving task was chosen in the present
study. Many kinds of puzzles induce our Aha!-experience which contains
involvements to the solution and sudden-insight. Originally Sudoku is a logic-based puzzle
which is solved by sudden-insight based on logic rather than inspiration. The
present study used 4x4 Sudoku which is a number placement puzzle. The objective
of our modified version of Sudoku is to fill a 4×4 grid with digits so that
each column, each row, and the center 2×2 sub-grid contain all of the digits
from 1 to 4. It is known that Broca’s area is activated by a number operation
task. To prevent such linguistic area from being activated, we used
corresponding colors to each number. In order to solve Sudoku, the first, we
have to search/guess the solution, the second, to evaluate the possible
solution, and then the third, to make us aware of the solution. Preliminary
data from MEG in Sudoku solving task shows that activities in the left
precuneus with a latency of -310 [ms](SE 13), L-PCG(the left posterior
cingulate gyrus) with a latency of -178[ms](SE 22), then L-ACG(the left
anterior cingulate gyrus) with a latency of -110[ms] (SE 26) appear preceded by
the subject’s button-press report for the solved moment of the puzzle. Subjects
report that the introspective impression for our color-Sudoku is similar to the
one for Aha!-moments. Such “Aha!-moment” can be restated by “moment of the
awareness”. We discuss the implications of our result for the neural mechanisms
of a moment of the awareness.
26. Propofol-induced
changes of brain activation and thalamocortical connectivity - interpreted from
information and integration.
Anthony Hudetz1,
Xiaolin Liu1, and Shi-Jiang Li1.
1
Medical College of
The reduced level of consciousness during general
anesthesia may be accompanied by altered neural activation and connectivity
within brain networks. We assessed propofol-induced changes of brain activation
and connectivity within different neural systems that are presumably
responsible for information and integration, which are essential to
consciousness. Based on a recent compelling view that the loss of consciousness
in anesthesia may be best described as "information received but not
perceived", we tested the hypothesis that with the administration of propofol,
there would be relatively stable neural activations to the perceptual
processing of verbal inputs, however, the neural substrates involved in
comprehension and memory, which require high-order integrating processes, would
exhibit significantly diminished. We also hypothesized that propofol would
suppress consciousness by inhibiting the nonspecific thalamocortical system,
which disrupts the integration of information; however, the specific thalamic
network for representing raw sensory information would remain relatively
intact. Eight healthy subjects listened to 200 high-frequency words during four
conditions: alert, light sedation, deep sedation, and return to alert baseline
during fMRI at 1.5T. Task-induced neural activations were extracted and thalamocortical
connections were evaluated respectively by the cross-correlation of
low-frequency filtered MRI time courses using seed voxels manually drawn from
either the specific or nonspecific (Intralaminar) thalamic nuclei. We found
that propofol significantly reduced BOLD activation in the left inferior
frontal gyrus, middle frontal and posterior temporal regions, previously found
involved in the encoding of sentences into memory or recognition of sentences
containing ambiguities. In contrast, the auditory cortex demonstrated resilient
activations across even under deep sedation wherein subjects showed no
conversational responses. Propofol also reduced task activations in the medial
parietal cortices that belong to the parietal default-mode-network (posterior
cingulate and precuneus) which play an important role in memory and continuous
monitoring of external and internal environments during resting-state. As
hypothesized, the specific thalamic network exhibited relatively stable
connections across both sedation conditions; whereas the nonspecific
connections were significantly reduced. These results suggest that anesthesia
impairs consciousness by primarily suppressing the neural systems involved in
high-level integration and the parietal default mode network.
27. Distinct oscillatory brain
activity in disorders of consciousness.
Manuel Schabus, Robert
Fellinger1, Caroline Schnakers1, Fabien Perrin1,
Roman Freunberger1, Wolfgang Klimesch1, Steven Laureys1.
Although bedside clinical evaluation of awareness
in disorders of consciousness (DOC) is inherently difficult it still remains
the clinical gold standard. We believe that the increasing use and refinement
of EEG and advanced EEG analyses techniques would improve our clinical
characterization of vegetative (VS), and minimally conscious state (MCS)
patients, not only for re(de)fining their diagnosis, but also to better
differentiate patients in terms of appropriate treatment (including
administration of analgesics and access to neuro-rehabilitation programs),
outcome and end-of-life decisions. In
the present study we focus on (residual) cognitive processing in a sample of 12
control subjects, 8 VS, and 13 MCS patients using bedside EEG, and hope to
provide new perspectives which might complement clinical diagnosis. We adopted
an approach using an “active paradigm” which explicitly asks subjects to follow
instructions, specifically to actively count own or other names as compared to
passively listening to them. Paradigms of that kind allow to identify awareness
in the complete absence of motor behavior. Bedside EEG data was then analyzed
using an advanced EEG analysis technique termed event-related synchronization/desynchronization
(ERS/ERD). Results reveal that MCS but
not VS patients show enhanced theta responses when instructed to count as
compared to passively listen to their own name. Interestingly, we also observed
a systematic delay in theta ERS (controls responding earlier than MCS than VS)
when participants were instructed to count their own name. We believe that this
reflects the systematic processing decrements according to the underlying
structural brain damage. Last but not least, alpha ERD – probably indicating
long-term memory access – is only clearly evident in control subjects when
instructed to actively count rather than merely listen to own names. Altogether data indicates that
time-frequency analyses allows to focus on distinct cognitive processes in DOC
and thereby contributes to a refined understanding of severely brain-injured
patients. It has to be clarified whether this information is sufficient in
order to guide diagnosis and to make statements regarding the further
development of these patients.
28. Brain
oscillations underlying conscious perception.
Bernhard Ross.
Rotman Research Institute,
Continuous sensory input provides a central
representation of the many elementary features of the environment. However, we
perceive an object in the world around us as an integrated entity. Thus, one
key question in the neuroscience of brain function is how sensory elements are
bound together for conscious perception. Neural oscillations at frequencies
around 40 Hz (gamma band) have been discussed since long time as mediating such
binding. Our model is that reciprocal thalamocortical connections form neural
loops, in which intrinsic oscillations in inhibitory interneurons entrain
synchronous oscillations in thalamic and cortical areas. Binding is established
as interaction between specific and non-specific thalamocortical circuits. We performed a series of experiments in
which we presented the subject with 40-Hz amplitude modulated sound and recorded the human magnetoencephalogram
(MEG). The 40-Hz rhythm of amplitude modulation elicits synchronizes
oscillations in thalamocortical networks, which can be detected in the MEG
signal noninvasively. We introduced subtle changes in the sound stimulus, which
were short temporal gaps, brief clicks to the opposite ear, or changes in sound
location, respectively. A common observation in those experiments was that a
stimulus modification resulted in a reset of the entrained brain oscillations.
The reset of 40-Hz oscillations was characterized by a 200 ms time interval in
which the response phase was delayed and the amplitude of oscillations build up
to its steady-state amplitude. We interpret this phenomenon as indicating the
process of resolving an existing binding when a new stimulus comes in and
establishing dynamically a new synchronous network representing the perceived
change in the stimulus configuration. With
MEG we can localize and map the nodes in the brain network generating 40-Hz
oscillations and can visualize the dynamics of activity with high temporal
resolution. Observing stimulus entrained oscillations provides the advantage of
a higher signal-to-noise ratio over the conventional approach of studying ongoing intrinsic brain activity
and opens a new avenue to study the neural mechanism underlying conscious
perception.
29. Perception
is a confidence game: Shared characteristics between consciousness and
blackboard systems.
Michael
Waterston.
Rotman Research Institute mwaterston@rotman-baycrest.on.ca
Global workspace theory posits that multiple
unconscious processes update a conscious representation of the world that is
shared between them. This is a
biological embodiment of the computer science concept of a blackboard
system. In a blackboard system multiple
knowledge sources update a common blackboard database to collaboratively solve
a problem. In robotics, blackboard systems
are useful for solving the problem of sensor fusion where data from multiple
noisy sensors must be combined to form a hypothesis about the state of the
outside world. Since global workspace
theory and blackboard systems are so closely related, it may be significant for
validating global workspace theory that features of successful blackboard
systems can be found in the awake brain.
Neurophysiological evidence for specific shared characteristics between
blackboard systems and consciousness will be presented. These common characteristics include
maintaining hypotheses at different levels of abstraction simultaneously,
tightly coupling the confidence in hypotheses with the hypothesis itself, a
control system (attention) that directs the flow of problem solving, and a
confidence-based model for updating uncertain hypotheses with new uncertain
data. New psychophysical results will be
presented demonstrating the role that perceptual confidence plays in the
integration of noisy visual and auditory motion signals. The practical solutions that computer
scientists have found to the problems of integrating noisy sensor data appear
remarkably similar to the techniques the awake brain uses to address its own
similar problem.
30. The
feeling of what happens in a game.
Tsugumi Takano1
and Ken Mogi2.
1Tokyo
2Sony
computer science laboratories
The
interaction with others (e.g. family, friends, and colleagues) plays an
important role in life, and has profound implications for the social
construction of the self in its conscious and unconscious manifestations. The
interaction between parents and child at the early stages of life has a long
standing influence on the subsequent social adjustment abilities. Attachment is
the affective bond of parent-child relation and supports the cognitive
development of a child, with the attachment figure in adulthood generalizing to
persons other than parents (Bowlby, J. 1991). Despite its importance in
childhood and the suggested continuation into adulthood, there has not been an
extensive study about attachment in adulthood, or the neural mechanism
underling the affective bond. Studies on
social reward provide important constraints on the nature of affective bond in
adulthood. Eye gaze activates the striatum associated with reward prediction
(Knut, K., et al. 2001), whereas social rewards activate the striatum in a
manner similar to the monetary reward (Izuma, K., et al. 2008). The anterior
cingulate cortex is activated by the distress of social exclusion (Eisenberger,
NI., et al. 2003). Here we study the
significance of the reliability and involvement of others as social rewards in
a game where the subjects interact with others and exchange monetary reward. We
examined the change in the actions and mental conditions of the subjects
induced by the interaction. From the video recording, correlations between eye
blinks and the subjects' reported mind states were analyzed. Our results show that the intentions of the
counterparts as manifested in the monetary rewards affect the subject's state
of mind, leading to various perceived feelings such as loneliness, sadness, and
sleepiness. It is suggested that gaming can provide a tool not only for
studying aspects of social behaviors such as altruism, but also for studying
the nature of mental state (e.g. feeling of isolation) induced by the
interaction. Finally, we discuss the potential of the current approach as a
tool for studying the social construction of the self in its conscious and
unconscious manifestations.
31. Decision-making
experiments under a philosophical perspective.
Gabriel Mograbi.
Federal University of Mato Grosso gabriel.mograbi@gmail.com
Decision-Making
is an intricate subject in neuroscience. It is often argued that laboratorial
research is not capable of dealing with the necessary complexity to study such
issue. Whereas philosophers in general neglect the physiological features that
constitute the main aspects of thought and behaviour, I advocate that a
philosophical analysis of cutting-edge experiments on decision-making can offer
us a framework to explain human behaviour in its relationship with will,
self-control, inhibition, emotion and reasoning. It s my contention that
self-control mechanisms can modulate more basic stimuli. Assuming the aforementioned standpoints, I
show the physiological mechanisms underlying social assessment and
decision-making. I also establish a difference between veridical and adaptive
decision-making useful to create experimental designs that can better mimic the
complexity of our day-by-day decisions
in more ecologically relevant laboratorial research. Veridical decision-making
presupposes the idea that of one of the answers is the only correct. Although,
the great majority of our choice is adaptive and don't have a unique
transpersonal correct answer. Adaptive decision-making, is particularly
dependent on the frontal lobes, differently from veridical decision-making. The
ecological relevance of experiments dealing with adaptive decision-making is
superior than of those dealing with veridical decision-making: Moreover, I
analyse some experiments in order to develop an epistemological reflection
about the necessary neural mechanisms to social assessment and decision-making.
Philosophically and technically analysing experiments, I show that attention
and inhibition are the key topics to understand how our choices are taken. I
critically analyse experiments on decision-making and conscious and subliminal
assessment aiming to show how inhibition and attention are related. I show that
attention and inhibition are necessary capacities to conscious decision-making.
The more semantically loaded and interpreted character of frontal lobes'
information processing constitute my epistemic credentials to sustain that
sheer determinism applied to living creatures, especially human beings is so
nonsensical as the metaphysical freedom of the will. I present empirical
evidence of how higher-cognitive functions could control more basic stimuli and
interpret that as the underlying necessary conditions to decision-making.
32. Does
Buddhist meditation facilitate prediction?
Hyun-Hee Kim.
University of the West harmoneek59@gmail.com
According to Libet’s experiment, the brain senses
what happens before the mind. Generally, human cognition lags in sense
perception, although individual's delay
differs. If the mind delays the comprehension of phenomena, then it is
questionable if controlling the mind by Buddhist meditation may prevent such
time lag. Meditation requires attention and increases attentional network of
neural circuit. [1] Given that attention modulates the speed of cognitive
process [2], our cognitive process can be temporally modified with attention by
meditation. According to Buddhist logic
[3], there are two instruments of valid means of cognition: perception
(pratyaksa) and inference (anumana). Perception implies the first moment of
cognition, and is followed by inference in the process of conceptualization.
Perception of meditating yogins is free from conceptual construction. Whereas
most people experience a delay in recognizing the present conscious moment,
yogins might reduce this temporal delay with lack of conceptual construction.
Meditation is free from the past-present-future boundary, realizing temporality
is merely an outcome of conceptualization.
In considering temporality, the record is always ‘past,’ and the
‘timeline’ is recognized as a record of events first occurring in the
‘present.’ We can construct a ‘timeline’ that expands into the future by
offering predictions based on probability algorithm. Supposing a Tibetan monk
can foretell incoming events in advance of the present time, the meditation
practitioner’s present corresponds to the non-practitioners’ future. This
interpretation might increase plausibility in the idea of seeing the future as
an action resulting from the conceptualization demarcating the three times that
establishes the sequence of temporal progress.
Given the alteration of attentional blink by meditation, the accurate
detection of target stimuli is increased by optimizing the neuronal resources
for stimuli. [4] Investigating meditation’s effects on temporality in relation
to neuroscience renders a new conceptualization of time, including the idea
that predicting the future is not irrelevant to our ordinary experience and can
be facilitated by meditation. I will discuss temporal latency of human
cognition, using an epistemological approach of Buddhist meditation, based on
the premise that consciousness creates time. [1] PNAS vol. 104, 2007. [2] Nature vol. 419 2002. [3] Hattori,
Masaaki. Dignaga, On Perception, 1968. [5] PLoS Biology Vol. 5, 2007.
33. Christian
and Buddhist contemplative science: does either inform neuroscience?
Michel Ferrari.
Human Development & Applied Psychology,
Alan Wallace—founder and president of the Santa
Barbara Institute for Consciousness Studies—has proposed that Buddhism and
neuroscience can meet in a new discipline that he calls ‘contemplative
science.’ Contemplation, from the Latin
contemplatio refers to a total devotion to revealing, clarifying and
manifesting the nature of reality.
Wallace claims that certain Buddhist practice provides a method for
empirically investigating human consciousness that provide a ‘telescope for the
mind.’ The empirical results this
practice generates about consciousness are said to be complementary to those
obtained using ‘hererophenomenological’ method advocated by Dennett and others
who deny the legitimacy of any first person science of consciousness. According
to Wallace (2007), who follows William James in this, we must guard against
confusing the rigor of the scientific method which gathers data through
observation and experiment with materialism; their association is said to be
merely a historical accident of 17th century mechanical science promoted by
Bacon, Descartes and others. But can
contemplative science provide information that is useful to neuroscience? An historical look at contemplative science
that compares Buddhist contemplative practices advocated by Wallace today with
those of historical and contemporary Christian contemplatives is very fruitful,
especially since researchers like Mario Beauregard and Paquette (2006) have
advocated a ‘spiritual neuroscience’ that seems very close to what Wallace
proposes. That both draw on radically
different metaphysical frameworks supports a point made by Ricoeur. Although Ricoeur (1992) agrees that
contemplative reflection is essential to human experience and to developing
personal identity, his blend of phenomenology and hermeneutic traditions lead
him to claim that any contemplative reflection can never be entirely free of
interpretations that frame our understanding of our own experience. What is
more, various discourses about self, God, neurobiology and contemplation may
never be reconciled (Changeaux & Ricoeur, 2000). However, all three approaches agree that
first-person experience is not an illusion. Our first-person experience is
itself testimony to our identity, and the refinement of that experience through
contemplative practices can give an ever more refined and nuanced quality of
the reality to which we testify.
34. Stress-reduction
and the cost of paying attention: focused attention vs. open awareness
meditation.
Ida Hallgren
Carlson.
Meditation
has been described as a group of various attentional and emotional regulatory
strategies (Lutz, Slagter, Dunne, & Davidson, 2008) and has also been
defined as a state of consciousness where deep relaxation and increased
internalized attention coexist (Murata, Takahashi, Hamada, Omori & Kosaka
2004). The present study investigated the relationship between focused
attention and relaxation during a focused attention type of meditation and an
open awareness type of meditation. Voluntary direction of one’s attention may
decrease stress, as measured by heart rate and heart rate variability (HRV). On
the other hand, sustained attention may create mental fatigue and a narrow
focus has been associated with stressful situations. To further explore the
relationship between focused attention and stress, meditation instructions
encouraging an open focus directed towards the background (e.g. the horizons) of
a visualized scene were hypothesized to show more stress-reduction, as measured
by HRV coherence, than narrow focused attention towards visualized objects in
similar scenes. In a pilot study HRV data was collected from 19 subjects with
none or little previous experience of meditation. A paired t-test showed no
difference between the focused and the open meditation. In the main study 24
subjects who had some previous meditation experience participated. Among those
who meditated more than 30 minutes per week (n=19) there was a significant
difference, t(18) = -4,111, p = 0,001 for low coherence and t(18) = 2,332, p =
0.032 for high coherence. 20 of the 24 subjects also reported experiencing the
open focus type of meditation as nicer or more calming, restful or relaxing. In
conclusion this paper suggests that experienced meditators may reach a more
harmonious state during an open focus emptiness meditation as compared to a
focused attention type of meditation, while subjects with no previous
meditation training may react differently to open meditation instructions.
Clinical implications are discussed.
35. Can
subjectivity be explained away?
Shun-Pin
Hsu1 and Allen Houng1.
1 National
Yang-Ming University sphsu@ym.edu.tw
While the scientific
frameworks are based on the third-person perspective without a subject,
subjectivity is the realest and the most mysterious phenomenon in our
consciousness. How do we explain subjectivity in a physical world? Mechanistic
explanations can provide a level-theory framework to explain a high-level
phenomenon by lower-level and higher-level phenomena (Bechtel, 2009). For
example, Metzinger’s phenomenal self-model theory of subjectivity gives a lower
mechanistic account of subjectivity by how representations operate to form a
self-model. Moreover, in a level-theory framework, William Bechtel argues that
we can accommodate both a reductionist’s perspective from lower-level
mechanistic explanations and an emergentist’s perspective from higher-level
mechanistic explanations, thus avoiding the commitment to mysterious high-level
ontology. However, without a commitment to high-level ontology, the
level-theory of explanations, I argue, is a kind of epistemic level-theory
differing from ontological level-theories, and an epistemic level-theory is a
reductionist’s theory that can’t account for downward causation. I argue that
the mechanistic view of level-theory just provides a new version of bridge laws
to theoretically reduce higher-level terms by a lower-level-theory, and the
level-theory, without ontological commitment to high-level entities, is just a
kind of reductive physicalism without emergent phenomena. In addition,
ontological level-theories can solve the problem of downward causation, which
is the most important aspect of subjectivity, by introducing lower-level
entities with boundary conditions (Houng, 2009). So, based on the level-theory
framework, we can’t explain away the involvement of the ontology of
subjectivity in a theory of subjectivity.
36. A
new way of explaining schizophrenia and the immunity to error through
misidentification.
Emma Chien1 and
Allen Y. Houng1.
1
National Yang-Ming University emmapchien@gmail.com
An important character
of self-consciousness is that when we use the first-person pronoun in a
self-referring way, it would be impossible for us to make a mistake. This
character of self-reference is called the ‘immunity to error through
misidentification relative to the first-person pronoun’ (IEM) (Shoemaker, 1968,
1996). Given that whether IEM is refuted by certain schizophrenic experiences
(including thought insertion, auditory hallucination, and delusions of control)
is yet to be decided, Gallagher (2000) suggests that this analysis implies that
a scientific explanation of the mechanism of these schizophrenic phenomena may
also account for how IEM works. Gallagher also suggests that Frith’s model
(1988, 1992) of the breakdown of self-monitoring in schizophrenia is a good candidate
for explaining IEM. This presentation has two aims. First, I will argue against
Gallagher’s suggestion that Frith’s model is a good candidate for explaining
IEM. The main reason is that Frith’s model of self-monitoring faces the
infinite regress problem. If part of a system monitors the whole system, this
monitoring part needs a sub-part to monitor the monitoring. Second, I will
argue that the nested hierarchical view of the self (Feinberg and Keenan, 2005)
provides a better explanation for schizophrenic phenomena and IEM because it
avoids the infinite regress problem. According to the nested hierarchical view
of the self, the brain is organized in an integrated multiple-level structure
whose highest level is the self. Schizophrenic experiences happen when
experiences fail to be integrated into the highest level of this structure.
When an experience successfully integrates into the highest level, this
experience becomes part of the self. Thus, the self cannot be wrong when
referring to the subject of this experience. This new way of explaining IEM
avoids the infinite regress problem because it does not presuppose a sub-system
that performs the self-monitoring.
37. An explanation of
consciousness. What is the explanandum?
Mads Jensen1 and
Asbjørn Steglich-Petersen1.
1
Cognitive Neuroscience Research Unit mje.mads@gmail.com
Consciousness is far from a clear and precisely
defined phenomenon (see e.g. Ned Block 2007) and many different questions can
be asked regarding consciousness. The explanandum – i.e. that to be explained –
of an explanation of consciousness is therefore ambiguous. This ambiguity
affects the explanandum as different events and phenomena require different
explanations and have different explanandums. Therefore, a single explanation
of consciousness will not be able to capture all the different aspects of
consciousness. I will here oppose the
idea of having one explanation of consciousness that explains every aspect. We
should expect the explanation to be composed of different parts, in which each
part explains a single event or phenomenon. However, we are not conscious of
one aspect at a time. Rather, we have unified conscious experiences integrating
multimodal aspects. I argue that we, therefore, need a framework able to
integrate several explanations, i.e. the set of explanation, into a unified
experience. I conclude that this
approach provide the possibilities of capturing the different aspects and
concepts connoted and denoted by consciousness. Thus, different explanandums
are possible and not a problem; they are a natural part of the overall
explanation of consciousness.
38. Explaining
the experience of succession.
Michal
Klincewicz.
If one accepts that
the succession of experiences is not the same as the experience of succession,
there are two ways of explaining the difference. The primitivist strategy posits a relation
between experiences that is itself experienced (Dainton 2005, Shoemaker 2003,
James 1895). On this view, succession
is a part of the content of an experience.
The constructivist strategy posits a mechanism, which retains the
just-had experiences in a sort of memory buffer (Gallagher 2003, Varela 1999,
Husserl 1928). On this view, succession
is interpolated from the contents of the buffer, but is never itself a part of
the content of an experience. Primitivist
views require that the subject be conscious of all the mental states bound by
the relevant relation. This implies that
at any given time at least two successive experiences are experienced
simultaneously. Similarly,
constructivism implies that just-had experienced continue to be experienced
when they are in the memory buffer. This
also implies that successive mental states are simultaneously conscious. These consequences are contrary to
experience. Normally, subjects do not
report seeing trails of moving objects, or hearing successive tones overlap
into chords. I develop constructivist
solution to this problem using David Rosenthal’s higher-order thought theory of
consciousness (Rosenthal 2005). On
Rosenthal’s view, a mental state is conscious only if the subject is conscious
of it in virtue of having a thought about himself as being in that very mental
state. On version of constructivism I
present, the subject is normally not conscious of the just-had experiences in
the memory buffer, and therefore never reports having them. Even though the subject is not conscious of
them, the just-had experiences contribute to the construction of an experience
of succession, about which the subject can report. I argue that only this kind of
constructivist view can yield a workable solution to the problem. This is because, unlike primitivism,
constructivism is not committed to the claim that a subject’s reports about
experiences are exhaustive of the reality of those experiences. Primitivism claims that succession is a basic
feature of any experience, because that is how it appears to subjects.
39. Do
we need the environment to determine the content of consciousness?
Ling-Fang Kuo1
and Allen Y. Houng1.
1
National Yang-Ming University sierra214135@gmail.com
In addition to our brain, what is sufficient for
the content of consciousness? Thomas Metzinger, an internalist, argues that the
stuff inside our body is sufficient to determine the content of consciousness.
In contract, Alva Noë claims that our brain is not enough to do that. Alva Noë
proposes that consciousness is constituted with the interaction between our
body and the environment. In his view, the environment is one constituent of
consciousness. The above two theories have different views when explaining our
conscious experience. For instance they disagree on explaining our dream
experiences. The internalists think that dream experience is like waking
experience, since the brain is sufficient for consciousness. Dream experience
is vivid and rich, so we can hardly distinguish dream experiences form the
reality. However, the externalists emphasis the external environment is a
constituted component of our experiences, so they argue that dream experience,
which is condition without externally constituted components of consciousness,
is fracture and not stable. In addition, they propose that dream is merely the
byproduct of the mechanism of consciousness. In this presentation, I will use
the research of REM sleep and dreaming, studied by Allan Hobson, to argue against
externalism. First, Dream has its’ own
specific function because it provides a virtual reality model of the world. So,
I argue that the mechanism of dream provides the fundamental elements to
develop our consciousness experience, and consciousness is born from the
closure box of body, rather than what externalist claim, consciousness is the
product of interaction between the body and the environment.
40. Extended
consciousness.
Andrew Brook.
The extended mind
hypothesis holds that the cognitive system can extend beyond the brain and
skin. In connection with this hypothesis, it is worth asking: How far can
consciousness extend? Even among those who favour the extended mind hypothesis,
some reject the idea that consciousness can extend beyond brain and skin,
though some of these researchers argue for it. Interestingly, none of the moves
that cut either for or against the extended mind hypothesis – not the parity
principle (for), not the range of proprioception or of control by a basic
action (against) – works for the issue of extended consciousness. If we look in
a different place, at the unified phenomenal field that is central to unified
consciousness, and ask what certain of its properties tell us about how far it
extends, however, we can make some progress.
41. Inattentional
blindness exemplifies consciousness without attention.
Benjamin
Kozuch.
Department of Philosophy,
One current debate in
consciousness research concerns whether attention is necessary for
consciousness. While some researchers have argued it is (Prinz 2000; O’Regan
& Noe 2001), others have denied this (Lamme 2004; Koch 2007; Block 2007).
Though experimental data have been brought to bear on this question (e.g.,
Sperling’s experiments with iconic memory, or studies involving unilateral
neglect), this has done little to settle the debate, since any given researcher
seems able to accommodate the data in question within his theory of the
relationship between consciousness and attention. In this paper, I argue that
the phenomenon of inattentional blindness is most likely an instance of
consciousness without attention. In an inattentional blindness paradigm (e.g.,
Simons & Chabris 1999), subjects often fail to notice an unexpected object
as it passes through their visual field, even when the unexpected object is
contextually bizarre (e.g., a man in a gorilla suit). In trials where the
subject cannot report upon the unexpected object, it is clear that the subject
is not attending to the object. (If she were, she could report upon it.) There
is, however, reason for thinking that such a subject is nonetheless
phenomenally conscious of at least some of the properties of the unexpected
object. One reasonable assumption to make about the phenomenology of the
subject is that she will be experiencing some color or another in the part of
the visual field occupied by the unexpected object. It is natural to think that
the color she experiences there will correspond to the color of the unexpected
object. It appears, then, that part of the subject’s experience is being
determined by a representation of a property of the unexpected object (its
color). We therefore should take subject to be, in some important sense,
conscious of the unexpected object. Viewed in this way, instances of
inattentional blindness appear to be instances of consciousness without
attention. I will argue this conclusion can be denied only by holding that
subjects lack color experiences in large parts of their foveal and parafoveal
visual field. Introspection makes this view of visual experience seem
implausible.
42. Intentionalism
and representational qualitative character.
Jacob Berger.
The
Some
mental states exhibit qualitative character, such as the bluish quality of a
visual sensation. Other mental states
exhibit intentional content, such as the content that it’s raining of a
belief. These properties are
traditionally thought to be distinct mental properties. Intentionalists, however, maintain that a
state’s qualitative character is identical with or supervenes on that state’s
intentional content. Some
intentionalists employ the Argument from Seeming (e.g., Byrne 2001, Thau 2002,
Lycan 2006), according to which whenever qualitative character changes, things
seem different to one. Since how things
seem depends on how they’re represented, it appears intentionalism
follows. This argument succeeds only
given the assumption that all representation is intentional. Though often assumed without argument, this
premise is questionable. I argue that
qualitative character is itself representational without thereby being
intentional. A change in qualitative
character may result in things’ seeming different not because of a change in
the way intentional content represents things, but because of a change in how qualitative
character itself represents things. And
if how things seem needn’t be due to intentional content, the argument
fails. Why think that qualitative
character may be representational without being intentional? Intentional contents can be true or false,
whereas mental qualities cannot be.
Moreover, intentional states exhibit both intentional content and mental
attitudes, such as belief and desire, toward that content; qualitative states,
by contrast, exhibit nothing like mental attitude. These folk-psychological observations suggest
that qualitative mentality is distinct from intentionality, but they’re
compatible with qualitative character’s being representational. A powerful theory of qualitative character
shows how mental qualities can be representational, but in a nonintentional
way. Quality-space theory (e.g., Sellars
1956, Rosenthal 2005) identifies and individuates mental qualities by their
relative positions within quality spaces that match the quality spaces of
corresponding perceptible properties.
This suggests that mental qualities represent those perceptible
properties. If undetectable quality
inversion is conceivable, then qualitatively distinct states could be identical
representationally and quality-space theory would fail. I argue, however, that such inversion isn’t
conceivable, since conceiving it requires assuming groundlessly that
qualitative character is only known first personally.
43. The
interactive representation of the motor control.
Hsi-wen Daniel
Liu.
Motor activities have been studied in terms of
anticipatory systems and goal-directed systems.
Do such activities bear content in any significant sense? This query seems hard to answer. On the one hand, such activities do not seem
to be completely meaningless; they seem to be grounded on certain
competence. Yet, on the other hand, the
motor activities are clearly not managed by thought. Motor activities, are considered in
Merleau-Ponty’s (1962) notion of motor intentionality as activities that are
between reflexes and deliberate actions (Kelly, 2000). Such activities, as Merleau-Ponty describes,
are controlled by “a motor power, a ‘motor project’ (Bewegungsentwurf), a
‘motor intentionality’ in the absence of which the order remains a dead letter
(Merleau-Ponty, 2006: 126-127)”. But,
the question remains as to what this “motor power” is. What sort of content do the motor activities
bear and what is its bearer—representation?
Grush (1997, 2004, 2007) and Pezzulo (2008)—two recent discussions on
anticipatory behaviors—affirm the importance of representation on the basis of
the standing-in-for relationship. The
present paper does not deny this, but would argue that motor activities primarily
bear the representational content that is not based on the standing-in-for
relationship, but instead on the interactive relationship manifested in
Bickhard’s (1993, 2000) account of interactive representation. The present paper discusses the control
structures of interactive representation and expounds them in the correction
loops of the motor activities. As is
argued, the interactive representation is genuine representation in the sense
that orders of interactive systems tightly connect (via interactive,
reciprocal, causal relationships) to orders of their performance. In addition, it is argued that some
interactive systems (as manifested in motor systems) are cognitive because they
maintain the accuracy of the goal-directed systems, and this is more implement
for being cognitive then being a Popperian creature. Two examples of interactive
systems—thermostat and the Watt Governor—are discussed with respect to the ways
in which the interactive representation turns up in those two examples. The conclusion is that motor systems bear the representational content on the basis of
the interactive representation.
44. Consciousness
and action control.
Myrto
Mylopoulos.
It is commonly held,
both in folk psychology and in formal theorizing, that consciousness and action
control are inextricably linked, in that the former is necessary for the
latter. I’ll call this the ‘Conscious
Control Principle’ (CCP). More
specifically, several theorists have argued that consciousness somehow enables
the following functions associated with action control: response inhibition,
action and target selection, and error correction. Evidence offered in support of CCP derives
from studies using a variety of experimental paradigms, e.g., the exclusion
task paradigm. Typically, these studies
purport to show that participants can perform certain control tasks, e.g.,
response inhibition, only when task-relevant mental states, e.g., perceptions
of task instructions, are conscious. The
inference is then drawn that consciousness enables that type of control
task. Further support for CCP relies
heavily on the dual system visual processing model championed by Milner and
Goodale (1995), which suggests that consciously available processing in the
ventral stream is responsible for action and target selection. In light of all this, should we accept
CCP? In this paper, I argue that we have
no compelling reason to do so, at least in its present form. First, I critically review the main empirical
results, and raise some conceptual and methodological worries. One concern is that it has not been established
by proponents of CCP that it is the property of being conscious that is making
the relevant difference, rather than a distinct property that merely co-occurs
with being conscious. A second concern
is that the central concepts of control and consciousness are being used by
some proponents of CCP in such a way that they presuppose the truth of the
principle. I argue that both of these
worries are worth taking seriously.
Next, I offer an explanation of why many are pre-theoretically tempted
to think that CCP is true. The
explanation appeals to the mechanisms that generate the sense of control we
typically have for our actions. Finally,
despite my criticisms, I offer considerations in favor of accepting a weaker
version of CCP, which claims that being in conscious mental states
*facilitates* action control.
45. The
eyes as the gate to the mind: when consciousness wanders, does the gate slam
shut?
Sarah Uzzaman1
and Steve Joordens2.
1 Univeristy
of
2
Univeristy of
Mindless
reading occurs when a reader’s consciousness drifts away from text
comprehension but their eyes continue to move across the page. While the
subjective experience of mindless reading is ubiquitous in real life, this
phenomenon has received little attention in the scientific community, primarily
because it is difficult to measure and manipulate in an objective empirical
manner. Previous experiments have established the existence of mindless reading
via subjective probing during reading periods. However, this method relies on
participants to be aware of the contents of their experiences, realize that
their mind have wandered away from the text, and then to report the
episodes. Eye movements provide a good
biological marker, and thus a potential objective indicator, that could be used
to conduct empirically rigorous studies of mindless reading. Tracking eye
movements creates a frame of reference for mindless reading, independent of the
participant’s subjective reports. In
this presentation, we will describe our attempts to determine the best
mathematical algorithm of eye movement indicators that distinguish normal
reading from mindless reading. Our
method involves first gathering data from the eyes in a task wherein participants
are occasionally probed for mindless reading; thereby allowing us to compare
the results of algorithms across trials where participants indicate their mind
was or was not wandering. Effective
algorithms are then further tested by using them to predict subjective reports
“a priori” with the results of the algorithm determining when participants are
probed.
46. Double
narrow content theory (DNC). Explaining phenomenal properties.
Miguel Ángel
Sebastián.
LOGOS-UB msebastian@gmail.com
When I undergo a visual experience as of a red
apple, there is something it is like for me to undergo it. A *redness* way to
undergo it. We can distinguish two different aspects of the experience: the
qualitative one (what it is like) and the subjective one (its for-meness). The theory I propose, the Double Narrow
Content Theory (DNC), tries to explain these two interrelated aspects
separately. The first part of the theory
provides an account of the qualitative aspect. The qualitative aspect is what
distinguishes among different experiences (for instance, an experience as of
red from an experience as of green), what makes an experience the kind of
experience it is. The theory I defend explains the qualitative aspect of an
experience by its (narrow) content. The
second part accounts for what makes of an experience a conscious one. A mental
state is conscious iff it has a subjective aspect. I claim that, in order to
explain the subjective aspect, we need to explain the kind of (pre-reflective)
self involved in a conscious experience. This is not the elaborate sense of
“self” we usually have in mind when we refer to a self. I am after some
primitive processes that constitute the basis of this elaborated self. A
proto-self (an antecedent of the self) can be identified, as the collection of
neural patterns representing the internal activity of the organism. The
interaction with the external world causes alterations in the internal states
reflected in the proto-self. The
subjective character or for-meness is, according to the DNC theory, explained
by the representation of the interaction between the object and the proto-self
and the phenomenal character of a mental state in virtue of its having a double
intentional content: “redness for-me”, With this theory I provide an unified
account for two aspects that are seldom distinguished.
47. Consciousness
and the tribunal of experience.
Richard Brown.
Ned Block has recently renewed his attack on
higher-order theories of consciousness.
In one recent paper, “Consciousness and Cognitive Access,” he has argued
that empirical evidence suggests that it is false. The basic argument is as
follows. We ought to evaluate theories of consciousness by how well they fit
over-all with the body of empirical evidence that we have (the mesh argument).
We have empirical evidence that seems to suggest that our phenomenology
overflows our ability to report. The view that phenomenally conscious states
can occur with cognitive access fits better with this data and so should be
adopted. As evidence he cites Sperling’s famous experiments. In that situation
the subjects has a phenomenally conscious experience of all of the letters but
is only able to report the letters in the row that they were cued. Block takes
this to be an objection to the higher-order theory since he thinks it is a case
of phenomenal consciousness without access. However, on a higher-order account
like that of David Rosenthal, there is a ready response. One is conscious of one’s own states in
various respects. So in the Sperling case the subjects are conscious of the
letters but just as letters not as determinate letters. The phenomenology does not
overflow access if this is true. The phenomenology is just that it seems to the
subjects that they are aware of all of the letters but not aware of each
letter’s identity and this is exactly what they report. So the higher-order
view meshes just as well with the data. The same turns out to be true of
Block’s other overflow example in the Landman experiments. In that case the
subjects are conscious of the array of objects and conscious of the shape that
differs, but not conscious of it as the difference. Thus it doesn’t seem to the
subject that there is a difference. What does overflow in this case is
information. So these results do show that there can be unconscious
representations but not phenomenally conscious states that we cannot access.
The methodological puzzle continues.
48. The
neuroanatomy of consciousness and the (multiple) boundaries of moral
significance.
Ilya Farber.
At
ASSC13 I argued that if we are serious about our theories of the neural basis
of consciousness, then we must take seriously their implications for assessing
consciousness in non-human animals. In that talk, I focused on the question of
how the most common theories might be combined with comparative neuroanatomy to
draw conclusions about the mere presence of basic sensory consciousness, which
is plausibly taken as a precondition for any sort of intrinsic moral status
(e.g. possessing rights or being the subject of pleasure and suffering). In
particular, I argued that animals such as fish, which demonstrably lack the
sorts of neural structures that are required for dynamical cross-sensory
feature binding, should be understood as lacking both consciousness and
intrinsic moral status. Within the realm
of conscious beings, however, both common sense and ethical theory routinely
draw further distinctions; almost everyone agrees that it is worse to kill a
human than to kill a mouse. In this talk I will explore what the neuroscience
of consciousness can contribute to such further distinctions, focusing on two
sub-types of consciousness which may mark off classes of animals with greater
moral significance: (1) consciousness
of self (2) social consciousness These hark back to approaches to
consciousness which arguably peaked in the early 00s and have seen less
attention of late (second-order/reflexive models and bodily
self-representation; theory of mind and mirror neurons). While I believe the
dynamic integration/GWT approach is superior as a foundational model, any such
model will nevertheless be more useful if it can also account for these further
distinctions. I will argue that this
constitutes a prima facie reason to favor neuroanatomically rich approaches to
consciousness (e.g. those which focus on thalamocortical dynamics) over those
which abstract away the anatomy to focus on numerical measures such as
Φ. In closing, I will
consider whether comparative neuroanatomy can help to clarify the boundaries of
these two narrower categories. I’m skeptical whether neuroanatomy is likely to
tell us much more about (2) than we can already gather from ethological and
experimental evidence, but the prospects for (1) seem somewhat better.
49. Operationalising
what?
Liz Irvine.
Operationalising what? The problem of whether reports or behaviours
are the best way of operationalising consciousness is particularly clear when
they conflict, such as in change and inattentional blindness (see e.g. Block,
2007, Mack & Rock, 2000). Based on
the idea of perception as hypothesis testing (see e.g. Friston, 2005), it is
argued that conflicting reports and behaviours are a natural product of a
multi-stream perceptual system. None of
these streams better reflect the real ‘contents of experience’, but the
existence of ‘default’ reported levels of hypothesis generation may explain our
intuitions about consciousness. Using
the case study of partial report superiority (Sperling, 1960, Landman et al., 2003,
Sligte et al., 2008), the different roles, informational input and time-frames
of gist and item-specific processing are explored. This shows how hypotheses determining reports
of scene gist (rich content) are produced in parallel to those that drive behavioural
capacities (sparse content). In
predictable environments, gist level hypotheses typically provide correct
descriptions of scenes and constitute our ‘default’ description of experience,
but in unpredictable environments gist level hypotheses may be incorrect (de
Gardelle et al., 2009). Conflicts
between rich reports and sparse behavioural capacity should not be seen in
terms of the amount of content in experience, but how accurate hypotheses are. Gist hypotheses are not indicative of the
‘illusion’ of richness, but they can be wrong in certain contexts. This model of report generation and
behavioural capacity in terms of multi-stream hypothesis generation suggests
that there is no ‘right’ way to operationalise consciousness. Different operationalisations (including
introspective techniques) access the products of different processing
streams. In this case, consciousness is
not a single stage or type of processing that can be better or worse accessed
using reports or behavioural tasks, but refers to a shifting range of more or
less detailed, and more or less accurate, hypotheses about the contents of an
environment. Research into hypothesis
generation in different perceptual streams can provide explanations of reports,
behaviours, and our intuitions about consciousness, and avoids the problems of
identifying the ‘correct’ operationalisation of consciousness.
50. Empirically
testing purported non-symbolic consciousness claims using standard
psychological methods.
Jeffery Martin.
Alleged non-symbolic experiences have been reported
for millennia. These experiences are often attributed to spiritual and
religious contexts, however atheists and agnostics also report them. They go by
many names, popular ones include: nondual awareness, enlightenment, mystical
experiences, peak experiences, transcendental experience, unity consciousness,
union with God, and so forth. Most non-symbolic experiences are temporary, but
some are reported as persistent. Virtually all of the information about
persistent forms comes from self report data.
No comprehensive empirical investigation of persistent forms of these
alleged experiences has been undertaken and completed. This presentation
focuses on one that is underway, and includes preliminary data as well as an
overview of the inquiry and what remains to be done. The overall inquiry
focuses on three phases comprising many data collection efforts, each of which
are quasi- or full experiments. The first phase involves obtaining
comprehensive psychometric profiles of individuals who self report these
experiences, as well as relevant qualitative data. Examples of measures used in
this phase include those covering: psychopathology, big 5 personality, anxiety,
absorption, and developmental levels. The second phase involves testing
psychological claims made by people who self report these states using well
validated psychological experiments. These claims are often considered untestable
because they are put forth in a spiritual or religious context, and frequently
used to refer to ‘ultimate’ truths. However, when viewed as psychological there
are many empirical tests and measures that can be used to examine the scope of
claims being made. For example, claims of ‘loss of a personal self’ and ‘unity’
can be tested from many angles. ‘Self,’ as these participants define it,
contains racial and gender bias, so loss of this ‘self’ should lead to scoring
low on covert tests for this type of bias. Claims of unbiased perception of the
world and of seeing ‘what is’ much more accurately can likewise be tested in
many ways, such as by using experiments involving visual inattentional
blindness. A third phase will commence after the first two are completed and
will focus on brain imaging based on the data collected in phases one and two.
51. How
'epi' are phenomena? -- Philosophical vs psychological epiphenomenalism.
Bill Faw
The word Phenomenon comes from philosophical Greek
referring to the appearing to one, of sense data, mental images, or thoughts in
the mind. Epi-phenomenon comes from more whimsical Greek for surface,
superficial appearances. To argue that
'consciousness' has causal efficacy -- does something to something --
necessitates (a) defining what consciousness is and (b) specifying what
consciousness does. Psychologist Max Velmans maintains that conscious
experience creates a phenomenal world around us, and thus allows the universe
to look in on itself, and that conscious experience is responsible for the
development of science, but denies that conscious experience has causal
efficacy, even in cognitive processing, citing Wegner, Libet, and others. Velmans appears to hold what I label a form
of empirical epiphenomenalism, which I argue is contradicted by the bulk of
modern consciousness science.
Philosopher Bill Robinson presents a form of philosophical
epiphenomenalism, in which phenomenalism and physicalism are given their due,
but never the twain shall meet. For
Robinson, the existence of tasks -- which can be done only through activation
of brain processes that also cause conscious events -- is not an argument
against epiphenomenalism. Dan Dennett
helps me articulate my intuitive sense that Velmans and Robinson mean very
different things by epiphenomenalism -- an empirical (psychological,
physiological) epiphenomenalism versus a philosophical epiphenomenalism. I make a case against empirical epiphenomenalism,
while remaining agnostic regarding philosophical epiphenomenalism -- presumably
the opposite moves that Dennett makes!
52. Implicit
coherence detection – how emotions regulate unconscious bases for intuitive
choice.
Joanna Sweklej1,
Robert Balas1, Grzegorz Pochwatko1, and Malgorzata
Godlewska1.
1
The presented research considers implicit
processing of semantic coherence. Previous research has shown that semantically
coherent word triads (i.e. three words that share a common associate) are
detected without conscious access to the fourth word (a solution). Furthermore,
this process can be facilitated or inhibited when the solution word induces
positive or negative affective response, respectively. Current research
examines to what extent semantic coherence detection is unconscious and
automatic. In two experiments participants were shown semantically coherent and
incoherent words triads and asked to judge their solvability either under dual
or single task conditions. The secondary task required constant monitoring of a
stimulus position on a computer screen and keeping it within limited space by
pressing the spacebar. The results have shown that under dual task the overall
accuracy of solutions decreased whereas the accuracy of solvability judgments
was intact compared to single-task conditions. This suggests processing of
semantic coherence to be indeed automatic and implicit. Detection of this
coherence might (but not always) be followed by conscious access to the
solution (insight), but this requires more effort and resources.
53. The
effect of intention-based and stimulus-based action in temporal reproduction.
Tomomitsu Herai1 and Ken Mogi2.
1
2 Sony
Computer Science Laboratories
Time perception is an essential aspect of human
consciousness. Despite its significance in mental life, the detailed mechanisms
of temporal processing are still unclear. States of intention (Haggard et al.
2002) and sensorimotor contingency (Moore & Haggard, 2008) are the key
components in constructing the subjective sense of time. Studies on the effect
of sensorimotor contingency on time perception often focused on the perceived
timing of events. Here we focused on the perception of duration, an important
aspect of temporal consciousness. Voluntary movements can be classified into
two types based on the trigger of action initiation, i.e., stimulus-based and
intention-based (Waszak et al. 2005). A stimulus-based action is triggered
externally, where the subject generates a movement as a response to a sensory
stimulus. In contrast, an intention-based action is driven internally without
the trigger stimulus. The stimulus-based and intention-based movements are
accompanied by differential senses of introspection. Waszak et al. (2005, 2006)
suggested that different neural mechanisms were engaged in these movements.
Based on the available neurophysiological evidences, we hypothesized that our
perception of duration would be differentially affected by sensorimotor
contingency in stimulus-based and intention-based movements. In the present experiment, we used the duration
reproduction paradigm, in which the subjects reproduced the interval of
reference durations (1,3 and 5[s]) by continuously pressing the key. In the
stimulus-based condition, the timing of the initiation of key pressing was
driven externally by a trigger stimulus. In the intention-based condition, the
subjects started the key pressing at their own timing. Results showed that the
subjects reproduced the reference duration significantly longer in the
intention-based condition than in the stimulus-based condition for the
durations of 3 and 5 [s]. There was no significant difference for 1[s]. These
results suggest that the perceived duration of time is affected by the nature
of action trigger.
The　specific nature of neural processes leading to the initiation
of action thus becomes an essential element of subjective time perception, to
be incorporated into the broader context of sensorimotor contingency.
54. The
hidden observer effect, cognitive effort and involuntariness: a real-simulator
investigation of streams of consciousness.
Shelagh Freedman1,
Joanne Downs1, and Jean-Roch Laurence1.
1
The notion of streams of consciousness is rooted in
the history of hypnosis. Revived and rejuvenated by Hilgard in 1979 under the
label of the Hidden Observer, the notion of dissociation and its latest
embodiment, the Hidden Observer, has been hotly debated amongst hypnosis
theorists and remains to this day controversial. According to Hilgard (1979),
some subjects while hypnotized, are able to experience the Hidden Observer
effect, a subjective experience of a “divided” consciousness . The present
study explored the Hidden Observer effect during hypnotic items of low, medium
and high difficulty index and assessed the role that demand characteristics
play in shaping real and simulator participants’ responses to this suggestion.
Sixty subjects who were previously screened on the Harvard Group Scale of
Hypnotic Susceptibility (HGSHS: A) participated in an individual hypnotic
session using a modified version of the Stanford Hypnotic Susceptibility Scale
(SHSS:C), with ten hypnotic suggestions and the introduction of the Hidden
Observer phenomenon. Those who had passed nine or more suggestions on the
HGSHS:A were classified as high hypnotizables (HiGroup), while those who passed
three or fewer suggestions were classified as low hypnotizables (LoGroup). A third group of participants (simulators;
SIMGroup) consisted of low hypnotizables asked to simulate being highly
hypnotizable to a blind experimenter. Subjects’ ratings of perceived effort and
involuntariness in carrying out six of the hypnotic suggestions (3 ideo-motor
suggestions; 2 challenge suggestions and a sour taste hallucination) were
compared to ratings obtained during the Hidden Observer condition, as well as
between groups. The results presented here have numerous implications both for
the validity of the concept of the Hidden Observer, and for theories that support
an altered state view of hypnosis. While the idea of diverse streams of
consciousness may feed into a more romantic view of the mind, it may be more
fruitful to view the Hidden Observer phenomenon as a temporary attentional
shift triggered and guided by extrinsic cues and intrinsic abilities.
Poster Session 2: Sunday, June 27th
Venue: St Patrick & St
David rooms (3rd Floor)
1. Unsupervised
visual one-shot learning as restoration of degraded images: a novel morphing
paradigm.
Tetsuo Ishikawa1
and Ken Mogi2.
1
2 Sony
Computer Science Laboratories, Inc.
Studying
various aspects of visual perception provides a salient tool for clarifying the
nature of awareness and consciousness. Considerable cognitive efforts are
needed to perceive surroundings in scotopic vision, as color information is
useless and spatial resolution is much lower than usual. The same holds true
for seeing hidden figures such as the grayscale picture of a cow (Dallenbach
1951) and the tow-tone image of a dalmatian (Gregory 1970). The segregation of
figure from ground is ambiguous in these degraded pictures. The dramatic
transition from an unconscious impasse to a conscious epiphany is thought to be
a special type of learning called visual one-shot learning. In the insightful
moment when subjects perceive “Mooney” faces (Mooney 1957), neural
synchronization spreads all over the brain which lasts for about 100
milliseconds (Rodoriguez et al. 1999). In general, when “Mooney” objects and
their original grayscale photographs are presented alternately, activities of
inferior temporal and parietal regions are enhanced (Dolan, et al. 1997), and
the early retinotopic cortex is modulated by top-down interpretation (Hsieh, et
al. 2010). The activation of left amygdala predicts memory performance one week
later in a similar paradigm (Ludmer, et al. in prep.), suggesting the
importance of emotional aspects of one-shot learning. The abrupt realization of
the hidden figure provides a robust experimental tool to investigate the nature
of conscious visual perception in its systematic and temporal richness. Here we
present a novel procedure to clarify the behavioral characteristics of
unsupervised visual one-shot learning involved in the perception of hidden
figures. By morphing “Mooney” objects with the original grayscale images,
figures of varied perceptual difficulties were produced. Through the variation
of morphing and temporal transition parameters, we constructed an external
means of controlling the perception of the figure in the conscious domain.
Morphing provides a means of dynamically probing into the cognitive processes
of one shot-learning, as opposed to the static approach of the conventional hidden
figure. Based on the analysis of
results, we shed light on the interaction of conscious and unconscious
processes involved, and discuss the implications in the context of findings in
the previous studies.
2. Physical
delay but not subjective delay determines the learning rate in prism
adaptation.
Hiroshi Imamizu1,
Kazuhiro Homma2, and Hirokazu Tanaka1.
1 NICT imamizu@gmail.com
2
Nagaoka University of Technology
Timing is critical in determining a causal relationship
between 2 events. Particularly in motor adaptation, to determine the preceding
control signals responsible for the subsequent error in a resultant movement,
the timings of the action and the results are extremely important. In prism
adaptation in humans and monkeys, an artificially induced temporal delay in
error feedback (as short as 50 ms) reduces the learning rate. However, recent
studies have shown that our sense of simultaneity is surprisingly flexible and
plastic when a persistent delay is introduced into the visual feedback timing
of our action. Therefore, judgment of 2 subjectively simultaneous events, or
subjective simultaneity, does not necessarily correspond to the simultaneity of
the physical events. Our study attempted to evaluate the effect of adaptation
to a temporal shift of subjective simultaneity on prism adaptation by
investigating whether prism adaptation depends on the physical timing or
subjective timing. First, the participants conducted 60 trials of pointing
movements in which the pointing location was shown after a short delay of 100
ms (delayed visual feedback). By measuring the points of subjective
simultaneity, we confirmed that the subjective temporal difference between the
time of pointing (when the participant touched the screen) and the time of
delayed visual feedback was significantly reduced (P < 0.01; paired t-test).
Thus, the participants’ subjective simultaneity adapted to the delay. Then,
while maintaining the temporal adaptation, the participants adapted to the spatial
displacement caused by a prism with the same delayed visual feedback. We
investigated the participants’ learning rate during the displacement and found
that the rate was significantly lower than the rate without the delay and not
significantly different from the rate with the delay (at P < 0.05 level
after correction for multiple comparisons by Tukey’s test). Therefore, our
results indicated that the learning rate was consistently predicted by physical
timing and not by subjective timing. Our result implies that prism adaptation
is independent of subjective timing awareness and may be dominated by
physiological processes in the primary motor areas that are considered to be
associated with physical temporal relationships.
3. Transfer of prior knowledge
in implicit learning.
Krzysztof Piotrowski1,
Zbigniew Stettner1, and Michal Wierzchon1.
1
Our research project aim is to check whether
natural-world rules acquired before implicit learning experience and then
incorporated into implicit learning task and built into the learning material
influence the way in which new rules are being learned implicitly. We also
investigate whether the organization of material (intrinsic rules) facilitate
or inhibit acquiring of new knowledge.
Three experiments addressed the question whether implicit learning
depends on rules associated with task material. All experiments used the same
basic procedure consisting of acquisition and classification phase. The
differences between experiments concern the structure of artificial grammar. We
used Markovian artificial grammar proposed by Dienes (experiment 1),
bicondicional grammar by Mathews (experiment 2), and our own non-sequential
grammar (experiment 3). The last one was composed to avoid the sequential
structure implemented in other grammars.
The strongest conclusion from the results so far is that the more
grammar is based on sequential rule the stronger learning effect is observed.
Participants are unable to learn grammars that non-sequential rules. It
suggests that similarity of natural-world rules built into the material to new
rules learned in the implicit learning task facilitate learning. We conclude
with proposals for further testing of this hypothesis.
4. How do we find words in
implicit artificial language learning?
Arnaud
Destrebecqz 1, Ana Franco1, and Axel Cleeremans1.
1
Université Libre de Bruxelles afranco@ulb.ac.be
Implicit learning is often viewed as a central
mechanism in natural language learning. In line with this idea, recent studies
have shown that infants and adults could identify the "words" of an
artificial language in which the only cues available for word segmentation are
the transitional probabilities between syllables. However, the exact nature of
the learning mechanisms and of the computational models that can account for
these results remains controversial.
According to one class of models, statistical learning amounts to parse
the speech stream by forming chunks between adjacent elements. In this view,
the sensitivity to statistical regularities is an emergent property following
from the acquisition of rigid, conscious, word-like representations. According
to a second class of models (the Sequential Recurrent Network, SRN) learning is
based on the computation of the statistical regularities present in the input.
The ability to extract words out of the speech stream is then rooted in the
processing of the basic statistical properties of the material. Learning occurs
automatically and implicitly and the knowledge of the words follows from the
flexible sensitivity to the transitional probabilities of the material. In order to contrast these two hypotheses, we
ran experimental and simulation studies in which we studied, within the context
of a Serial Reaction Time (SRT) task, the participants' and model's ability (1)
to process statistical contingencies between non-adjacent elements and (2) to
flexibly learn different artificial languages composed of a different set of
words but sharing the same transitions between successive elements. These two
kinds of linguistic regularities are indeed particularly challenging for models
based on chunking processes. Our results
show that the SRN can account for the essential features of human behavior
suggesting that implicit statistical learning might be more powerful than
previously anticipated and can indeed constitute a central mechanism of
language processing.
5. Measuring
consciousness in implicit learning process.
Agnieszka
Poplawska1 and Alina Kolanczyk1.
1
The
aim of the presented study is to establish what kind of procedure would be more
sensitive in assessing nonconscious learning processes in a artificial grammar
learning task (Manza, Bornstein, 1995). In AGL task subjects are asked to
remember some set of letter strings which are built by using rule system. The
main finding is above-chance level classification of novel letter strings which
are generated from the same rule system with little, if any, conscious
knowledge of the underlying rules of grammar. Lots of researchers assert that
AGL may be mediated by explicit learning processes. The main problem is that
subjects are informed of rule system existence prior to the classification task
so they could use this explicit information to guide their subsequent
classifications. Manza and Bornstein (1995) proposed to use method based on
mere exposure effect paradigm. This effect occurs when exposure to unfamiliar
stimuli lead to an increase in positive affect toward this stimuli. So they
proposed using liking task in AGL as more sensitive measure of implicit
learning process rather than rule-conformity task. In presented study
participants were divided into four groups. Experimental groups had to memorize
grammatical strings of letters as in standard artificial grammar learning
procedure. Control groups did not learn anything. Next, one experimental group
was asked for classification task – if letter string is grammar or not. The
second one was asked for liking task – they decided about liking letter strings
or not. The same classification task did both control groups. The results
indicate that participants making rule-conformity judgments were more correct
than participants who made liking decision. It means that subjects have some
conscious knowledge of artificial grammar and information about rule system existence
can lead to increase of correctness in AGL classification task.
6. Semantic
eye-blink conditioning; a paradigm to test abstract categorization and learning
in DOC.
Moos Peeters1,
1
Faculty of Psychology and Neuroscience,
moos.peeters@mrc-cbu.cam.ac.uk
2 MRC Cognition and Brain Sciences Unit
The presence of conscious processing relies on
voluntary overt responses. Patients suffering from disorders of consciousness
(DOC; vegetative state, minimally conscious state), however, do not overtly
respond to external cues, thereby posing difficulties when assessing their
residual cognition and awareness. Recent studies have focussed on two main
aspects of consciousness in DOC - the understanding of language, and the
ability to show trace conditioning. A
well established language task, made up of several hierarchical aspects: (1) auditory
processes, (2) speech-specific processing, and (3) semantic information, has
already shown to be of great value in indicating the extent of residual
language comprehension in DOC patients (Coleman et al., 2007, 2009). In addition race conditioning, known to rely
on awareness, requiring explicit declarative knowledge of the temporal
contingency of the stimuli, has been shown in a subset DOC (Bekinschtein et
al., 2009). The current study brings
these two aspects together into one paradigm.
Rather than tones, words are used as the conditioning stimuli in a
differential eye-blink trace paradigm in which the semantic category of the
stimulus (animal/object) predicts a subsequent air-puff delivered to the eye.
In order to decipher the predictive value of a stimulus the individual must
rely on abstract features of the stimuli than simple tone discrimination. To our knowledge, there have been no previous
studies of semantic conditioning. The
purpose of the present study is to provide control data from healthy volunteers
in order to establish the validity of this paradigm. Data from the control
group will be presented, along with some preliminary data from DOC patients.
We’ll discuss the efficacy of this test as an affordable and simple bed-side
test to establish aspects of residual cognition and awareness.
7. EEG correlates of conscious
versus unconscious knowledge in artificial grammar learning.
Lulu Wan1, Zoltan
Dienes2, I-Fan Su1, and Xiaolan Fu1.
1 Institute
of Psychology, Chinese
2 University
of
The current study investigated the neural
correlates of knowledge and the conscious status of knowledge in artificial
grammar learning. In the training stage, subjects were exposed to grammatical
strings which were displayed one letter a time. Subjects were asked to type the
string back. In the test stage, subjects classified strings as to whether they
had the same structure as the training strings. Then they indicated the basis
of that judgment: guessing, intuition, familiarity, rules or memory. Tests
strings violated repetition structure in the final (fifth) letter. In the test
stage, the electroencephalogram was recorded while the fifth letter of each
string was displayed. We were interested in two event-related potential (ERP)
contrasts: 1) grammatical strings versus matching ungrammatical strings which
violated repetition structure; 2) unconscious structural knowledge attributions
(random, intuition, and familiarity) versus conscious structural knowledge attributions
(rules and recollection) when subjects classified correctly. Ungrammatical
rather than grammatical strings elicited greater N2 amplitude at the frontal
electrode positions (Fpz/Fz/F4/F6), indicating that N2 amplitude is a useful
marker of knowledge of grammaticality. Additionally, the P300 component was
higher for conscious rather than unconscious attributions at frontal-central
electrode positions (FCz/Cz C3/C5), indicating P300 is a useful marker of the
conscious status of structural knowledge.
8. Conscious
and unconscious thought in implicit learning.
Andy Mealor1
and Zoltan Dienes1.
1
University of
Unconscious Thought Theory has recently received
considerable interest in the area of cognition. It posits a period of
distraction after stimulus presentation leads to unconscious processing and can
enhance decision making relative to conscious deliberation or immediate choice
(Dijksterhuis, 2004; Dijksterhuis & Nordgren, 2006). Support thus far has
been mixed. In the present study, intermediate phases were introduced into the
artificial grammar learning paradigm between training and testing. Participants
engaged in conscious deliberation of grammar rules, were distracted with an
unrelated mathematical task for the same period of time, or else progressed
immediately from training to testing. In the test phase, the conscious status
of participant’s structural knowledge was assessed using the method of Dienes
and Scott (2005). There was a significant interaction between intermediate
phase and structural knowledge type (conscious or unconscious). Immediate
progression and distraction led to higher classification accuracy based on
unconscious knowledge than rule discovery. Conversely, rule discovery and
distraction yielded higher classification accuracy based on conscious knowledge
than immediate progression. Thus, no evidence of unconscious thinking was
found. Distracted participants performed as well as immediately progressing
participants in terms of unconscious knowledge and as well as rule discoverers
in terms of conscious knowledge. Results suggest both conscious deliberation
and distraction promote conscious knowledge in a complex rule-based task.
Furthermore, conscious deliberation deteriorates the quality of intuitive
responses relative to distraction or immediate decision making. Hence,
beneficial effects of a distraction condition cannot automatically be taken to
indicate unconscious thought.
9. Transient
neglect: visual working memory mediates conscious visual perception.
Stephen Emrich1, Hana Burianová2, and Susanne Ferber1.
1
University of
2
What are the neural processes that support
conscious visual perception? Evidence may come from visual neglect, a
neurological disorder in which patients display profound impairments in
conscious awareness for visual stimuli in the contralateral visual field.
Visual neglect typically occurs following lesions around the right
temporoparietal junction (TPJ), and is characterized by deficits in selective
visual attention, and visual working memory (VWM) performance. Functional
magnetic resonance imaging (fMRI) studies have identified brain areas that show
VWM load-dependent activity: the bilateral intraparietal sulci (IPS), lateral
occipital (LO) cortex, and anterior cingulate regions show an increase in
activation with load, whereas the right TPJ becomes increasingly deactivated
with increasing VWM load. In the current study, we tested whether increases in
VWM load and the concurrent deactivation in the right TPJ may be associated
with lateralized impairments in conscious visual perception. Our behavioural
results demonstrate that conscious report for objects presented under a
high-VWM load is impaired relative to a low-VWM load, and that recognition
performance was worse for bilaterally presented objects. Interestingly object
recognition performance was significantly impaired for items presented in the
left visual field, but only under a high-VWM load. Thus, the behavioral results
resemble the deficits observed in visual neglect, as conscious visual
perception was impaired for objects presented in the left visual field under a high-VWM
load. Using multivariate fMRI analyses techniques, we further demonstrated that
activation in VWM regions increased with both VWM load and number of objects
presented. Furthermore, this activation was strongly correlated with object
recognition performance. The timing of activity also suggested that the amount
of information that reaches the levels of processing necessary for conscious
object perception may be limited by capacity-limited VWM resources. Therefore,
our results provide evidence that information must not only be attended, but
must also be processed in VWM before it can be accessed at the conscious level.
In other words, when cognitive and neural VWM resources are depleted, conscious
object recognition is impaired. These findings provide insights into the
cognitive and neural processes that support visual awareness of a given
percept.
10. Trade-off
in the effect of attention for visual short term memory.
Eiichi Hoshino1
and Ken Mogi2.
1
2 Sony
Computer Science Laboratories
Failures of perception such as change blindness
(Rensink et al. 1997) provide insights into the nature of visual consciousness.
Visual short term memory is an important constituent of visual awareness in its
temporal manifestations. Paying attention to a particular aspect of an object
tend to reduce vulnerability in memory probes in that context (Makovski et al.
2008,
11. Perceptual
object priming in the absence of recognition memory.
Carlos Alexandre
Gomes1 and Andrew R. Mayes1.
1
University of
Priming
is a phenomenon whereby a previous encounter with a stimulus enhances the
ability (e.g. faster reaction times (RTs)) to classify, identify or produce the
same or a related stimulus. Although priming has been extensively studied, very
little is known about when perceptual object priming can occur under conditions
of inattention and with total absence of recognition memory. In experiment 1,
participants studied line drawing pictures of objects in two encoding
conditions: deep (animacy decision) and shallow (identifying the number of red
dots presented within an image). At test, they engaged in an object decision
task (ODT) in which pictures of real and unreal objects were presented very
briefly (30 ms) followed by a recognition memory test. Significant priming,
measured through RTs during the ODT, was observed for studied (deep + shallow)
objects, indicating that participants were faster overall for studied than for
unstudied/new objects. When the data were split into three conditions (deep,
shallow and new) a strong trend to significant priming was obtained, but only
shallowly encoded objects showed significantly faster RTs than new objects.
Critically, both unrecognised deeply and shallowly encoded objects were judged
significantly faster than new objects. However, an interaction between
condition and memory approached significance, indicating that recognition
memory awareness slowed participants down to a greater extent on deeply than on
shallowly processed objects. In order to understand if this memory awareness
could have been responsible for the lack of priming for deeply processed
objects overall, experiment 2 was designed so that a group of participants
performed the object decision task while another group was engaged in a
recognition memory test. Here, significant priming was observed for both deeply
and shallowly processed objects, confirming that recognition memory awareness
may have indeed affected RTs of deeply (but not shallowly) encoded objects in
the first experiment. To our knowledge, these experiments have been the first
to observe perceptual object priming in which, even under conditions of
inattention (conscious processing of stimuli was not required in the shallow
task), participants retained an unconscious perceptual record of objects which
improved their performance in a subsequent perceptual test.
12. Ouija
and the ideomotor effect: when implicit memory turns explicit.
Helene Gauchou1
and Ronald Rensink1.
1 Visual
Cognition Lab UBC helene.gauchou@gmail.com
The ideomotor effect (Carpenter, 1852) is the production
of actions that are unconsciously initiated, strongly associated with a loss of
the sense of agency, and convey a thought rather than respond to sensory
stimulation. A commonly known example of this is the Ouija game. Here, a
movable indicator (planchette) is placed upon a flat board marked with letters,
numbers, and the words “yes” and “no”. Players ask a question, position their
fingers on the planchette and follow it as it moves about the board to spell
out messages. Two important characteristics of Ouija are the absence of a sense
of agency, and the meaningfulness of the answers. We propose using Ouija to
explore the ideomotor effect--in particular, to determine if meaningful answers
can be obtained in the absence of conscious thought. In this presentation we describe the results
of a preliminary study comparing access to semantic long term memory with and
without the use of a Ouija board. In the Non-Ouija condition participants
answer questions by “yes” or “no” according to what they think, and rate the
confidence level of their response. In the Ouija condition they are presented
with the same questions but use the Ouija board, following the planchette when
it moves toward the “yes” or “no” answer without interfering with its movement.
A necessary condition for the ideomotor effect is that the player attributes
the origin of the movement to an external source. To accomplish this, each
participant is paired with an experimenter pretending to be another
participant. The real participant is then blindfolded, so he cannot see that he
is the only one touching the planchette. Performance is then analyzed as a
function of the conditions (Ouija / Non-Ouija) and confidence level.
Preliminary results indicate that in the Non-Ouija condition participants guess
the percentage of correct answers at chance levels; when the same questions are
answered with the Ouija board the percentage of correct answers significantly
increases. This suggests that ideomotor
effect may be useful in determining the contents of implicit memory.
13. Recognition
memory with or without subjective confidence: qualitative differences. Heather
Sheridan1 and Eyal M. Reingold1.
1
University of
A variety of evidence suggests that recognition
memory is not process pure. In light of this evidence, our goal is to establish
the effectiveness of a variety of subjective measures at distinguishing between
different components of recognition memory. Subjective, or “claimed awareness”,
measures require the observer or the rememberer to report on their subjective
phenomenal awareness while performing an experimental task. To establish the
validity of these measures, we tested for qualitative dissociations between
recognition memory judgments that were made in the presence versus the absence
of subjective confidence. The experiments employed a generate read manipulation
at encoding. At test, three main paradigms were used to assess participants’ subjective
confidence at the time of retrieval. The first paradigm required participants
to make a 2 alternative forced choice (2AFC) memory judgment concerning which
of two words was old, and then to rate (on a scale from one to four) how
confident they were in the accuracy of this decision. The second paradigm
presented three words at test (one old, two new). Participants had to decide
which of the three words was old, and then to make a second choice concerning
which of the remaining two words was more likely to be old. The third paradigm
was an adaptation of the unconscious perception paradigm developed by Merikle
and Reingold (1990). On each trial during test, two words were presented (50%
of trials = two new words, 50% = one new word, one old word). Participants
answered 2 questions: 1. Is either word old? (response options in Experiment A:
strong yes, weak yes, weak no, or strong no; response options in Experiment B:
remember, know, or new) and 2. Which word is old? We examined question 2
performance contingent on whether the participant made an old or a new response
during question 1. Overall, we report evidence that participants can be above
chance on a 2AFC memory task in the absence of subjective confidence.
Importantly, we also discuss evidence for dissociations between memory
performance in the presence versus the absence of subjective confidence at the
time of retrieval.
14. The
duration of awareness during interocular suppression correlates with subsequent
memory.
Diego Mendoza1
and Avi Chaudhuri1.
1
Presenting dynamic noise to one eye can completely
suppress conscious perception of stimuli presented to the other eye for long
periods of time. At particular stimuli contrasts, interocular suppression is
occasionally interrupted, leading to periods of awareness. Here, we
investigated the relationship between the duration of awareness of visual
objects and the strength of subsequent memory. Subjects were exposed to visual
objects under interocular suppression while they reported periods of object
awareness. Memory for these objects was later tested with a 2-alternative
forced choice discrimination task, followed by a confidence judgement of the
response. We found that discrimination performance was at chance for objects
that were never consciously perceived, but significantly above chance for
objects that were perceived for at least a fraction of the presentation period.
Moreover, discrimination performance for perceived objects increased with
increasing duration of awareness, and resembled the performance obtained for
control objects that were binocularly presented for periods that mimicked
subjects’ reports of awareness. For perceived objects, discrimination responses
were more often correct when followed by a high-confidence judgement than by a
low-confidence judgement. In contrast, for unperceived objects, the frequency
of correct responses followed by high- and low-confidence judgements was equal,
both at chance level. Thus, confidence judgements reflected memory performance
for perceived objects but not for unperceived objects. Taken together, our
results suggest that discrimination memory depends entirely on the access of
visual objects to awareness, and thus support the use of discrimination memory
performance as a reliable and objective measure of conscious perception.
15. Anosognosia
of memory impairment in dementia: a population-based study.
Daneil Mograbi1,
Robin Morris1, and Cleusa Ferri1.
1 Instiute
of Psychiatry, King's College London daniel.mograbi@kcl.ac.uk
Objectives: This study investigated the prevalence
of anosognosia of memory impairment in dementia in large surveys from different
international regions. As a subsidiary aim it investigated socio-demographic
and health correlates of anosognosia, and also the association of anosognosia
with cognitive variables and behavioural and psychological symptoms of dementia
(BPSD). Design: Cross-sectional
population-based survey. Settings:
Community samples (n=15,022) from three world regions (
16. In
and out of consciousness: The role of visual short-term memory.
1
University of
What is involved in maintaining a visual percept in
conscious awareness? We approached this question by using a typical
shape-from-motion (SFM) display, in which fragmented line-drawings of an object
move relative to a background of randomly oriented lines. When static, the
fragmented line-drawings are indistinguishable from the noisy background, but
when motion is added, observers become aware of the figure. The resulting
percept of the object persists after the motion has stopped (stop condition),
but only briefly, as it very quickly disintegrates into the noisy background.
Despite one’s continued effort to maintain the percept and in the absence of
any change in the content of the perceptual array, the coherent figure is
rendered inaccessible to awareness. Interestingly, when the lines are removed
after motion off-set (vanish condition) the figure is no-longer perceived,
suggesting that the persistence and fading of this visual percept is not merely
a function of motion-induced neural activity. We wanted to examine whether
visual short-term memory (VSTM) is involved in sustaining a coherent percept
during the persistence period and whether VSTM may be a precondition for
phenomenal consciousness. Participants observed SFM displays that were
presented bilaterally and were asked to indicate, with a button press, how long
the object percept persisted after the motion stopped. While participants
performed this task, we measured their brain activity using electroencephalography
(EEG). Specifically, we examined the contralateral delay activity (CDA) which
is a negative ERP waveform computed as the difference between contralateral and
ipsilateral activity and whose amplitude correlates with the maintenance of
items in VSTM. In other words, we used a neural index of VSTM to test for its
involvement in self-reported perceptual awareness. We observed a greater
negativity (larger CDA amplitude) for the stop condition compared to the vanish
condition, which correlated with subjective reports of persistence. This
suggests that VSTM plays an important role in maintaining a visual percept and
may be a necessary condition for phenomenal consciousness.
17. The
phenomenology of personal wisdom in younger and older Canadian adults.
Michel Ferrari1,
Nic Weststrate1, Anda Petro1, and Roshan Annalingam1.
1 University
of
Although wisdom has a wide range of historically
specific meanings, the oldest and most common sense of wisdom refers to the
human ability to personally cope with life by discerning patterns that lead to
success. Scientifically, wisdom has been
studied in several ways, but most naturalistically through implicit theories of
wisdom held by people of different ages, religions, and nationalities (Clayton
& Birren, 1980; Takahashi & Bordia, 2000) and through autobiographic
accounts of moments of personal wisdom (Bluck & Glück, 2004). As part of a large-scale cross-cultural study
of wisdom, 60 Canadian men and women (50 age 21-30 and 10 aged 65-85; half
women) participated in this study, consisting of a single session lasting 1 to
3 hours. Participants first completed a demographic questionnaire. Second, they participated in a
semi-structured interview that first asked about their life experience, and in
particular their experience of wisdom: (1) a time when a personal acquaintance
had demonstrated wisdom, (2) a time when the participant had demonstrated
wisdom, and (3) an account of an historical figure had demonstrated
wisdom. Finally, they were asked to
define wisdom. Participants ended the session by completing psychometric
assessments of wisdom and quality of life. All interviews were transcribed and content-coded
according a coding manual inductively derived for the purpose of analysis based
on the work of Ardelt (2003) and others using a phenomenological method. Each
was then examined using a content-driven master narrative positioning analysis
developed for this study (adapted from Thorne & McLean, 2003). Such an
analysis assumes that the development and maintenance of personal narratives
(in private discourse) is necessarily framed by overarching, prototypical
stories found in public discourse (Harré et al., 2009). Preliminary results found
that, as compared to younger participants, older participants show no
statistical difference in Life Satisfaction, but greater Self-Transcendence,
and greater General Well-Being, with no gender differences for either age
group. But younger and older individuals of both genders who score higher on
Ardelt’s 3 dimensions of Wisdom Scale differed in their wisdom stories,
suggesting that first-person experience of wisdom is not only a matter of age,
but of perspective on life.
18. Lessons
from pain science: phenomenology and structure in the scientific study of
consciousness.
Sascha M. B.
Fink.
Pain
Science is paradigmatic as a scientific study of consciousness (SSC) due to its
successful history of manipulating one specific phenomenal content: pain (Ayede
and Güzeldere 2005). Then, however, SSC is necessarily dependent on
phenomenological judgements (PJ), as I argue. First, due to the explication of
"pain": To fragment the everyday notion of "Pain" into scientifically
researchable subparts, one is relying on first-person accounts; e.g. Grahek
(2007) established the distinction of "feeling pain" and "being
in pain" by analysing phenomenological reports of pathological cases, thereby
distinguishing clearly between pain asymbolia, analgesia and paradigmatic
pains. Secondly, it is widely accepted among pain scientists that the
experiencer has authority whether she feels pain or not (Thomm 2005; IASP
1986). Thirdly, among the diagnostic criteria of most pain phenomena are
phenomenological as well as neurological symptoms (e.g. Freynhagen and Baron
2006, 39ff; IASP 1986; ICD-9, 330ff); and in those cases where pain serves as a
perception, doctors rely on transindividual stabilities in PJs to diagnose the
underlying cause: An ache refers to an intestinal cause, a stinging pain is
nerval and a burning pain is reveals muscular damage (Tye 2006). Therefore, SSC
depends on PJs. PJs can be data to be analysed, but also predictions, as demonstrated
in Churchland's "Chimerical Colours" (2005). Thus, PJs are a
necessary part of theories of consciousness. The specific stabilities in PJs
inform about an abstract level of phenomenal structure, but not about intrinsic
what-it-is-like-ness. Analysed as a claim for necessity, PJs can be falsified
by phenomenological case studies, which is the underlying argumentative scheme
of neurophenomenology. Given the additional premise that structural realism is
true (Ladyman 1998; Ladyman and Ross 2007), knowledge about structures is the
only scientific knowledge existing. As long as PJs are as falsifiable as any
other scientific judgement and one analyses them as providing structural
information, then their usage does not endanger SSC of becoming dogmatic or dualistic.
Also, the structural properties of phenomenality can be seen as emergent from
deeper neural structures, also without entailing a form of dualism. In the
framework of ontic structural realism, then, nothing is left to explain.
19. The
detectable consciousness and the phenomenology.
Chihyi Hung1
and Allen Houng2.
1
Institute of Philosophy of Mind and Cognition jh.philo@gmail.com
2 IPMC,
NYMU
Whether phenomenal consciousness includes the
cognitive accessibility underlying reportability has long been a fray. Ned
Block initiated the distinction between the phenomenal-consciousness and the
access-consciousness among the mongrel concepts connoted and different
phenomena denoted to avoid conflation in the research of consciousness. Per his
definition, the phenomenal-consciousness is experience; the phenomenally
conscious aspect of a state is what it is like to be in that state. The
access-consciousness is availability for use in reasoning and rationally guiding
speech and action. Phenomenal-consciousness remains a first-person datum which
no objective measurement can immediately access. This makes reportability
seemingly inevitable for verification of conscious states and thus leads in a
circle which is called “the methodological puzzle of consciousness research” by
Block. The debate over reportability of phenomenology would preclude concernful
clinical evidence of patients with disorders of consciousness(DOC). Within the
past decade, the rapid developments in the field of neuroimaging have played a
substantial role in the assessment of patients diagnosed with DOC by providing
new prognostic indicators from the residual functions examined among patients
of such to reduce diagnostic errors between vegetative and minimally conscious
state. Recent studies show that the self-referential stimulus (call subject’s
own name) evokes residual brain activity by eliciting MMN in patients with
DOC(Qin, 2008). These evidences imply their ability to create and utilize
neuronal representations of the immediate sensory auditory environment
(Näätänen et al., 2007). Some other studies using fMRI claim that patients with
a diagnosis of being in a vegetative state were able to modulate their brain
activity by generating voluntary, reliable and repeatable BOLD responses when
prompted to perform imagery tasks (Monti, 2010). The states that seem
unreportable, nevertheless can be detected by using “indirect” techniques and
objective measurement redefines some conscious states further to the phenomenal-consciousness
defined by Block. We posited “the detectable consciousness” as a distinctive
category that helps clarify the phenomenology and the definition of conscious
states related to this sort apart from the hard problems and provide a clearer
scope on the related researches on comatose states, dream state, mental imagery
and memory etc.
20. The
phenomenology of cognition: What is it like to be my thought?
David Tostenson.
I argue that occurrent cognitive activity does
have a distinctive phenomenal character. Specifically, occurrent cognitive
activity typically seems like our own cognitive activity, rather than some kind
of alien intrusion. There is, in other words, a specific kind of phenomenal
experience of “ownership” of mental states. When this phenomenal experience is
absent, distressing symptoms of mental illness occur—witness the schizophrenic
subject’s complaint that someone else is inserting thoughts into his mind
against his will. I also argue that certain specific types of occurrent
cognitive state, such as the experience of suddenly seeing the solution to a
problem, are also clearly phenomenally endowed, and the phenomenal character of
such an experience is the experience of a change in the character of our
cognition, not simply the experience of a “flash in the dark.” Once it is
established that there is a phenomenology of occurrent cognition, the question
is then what this fact means for psychology. I argue that it is possible that
the kinds of sub-personal cognition appealed to in cognitive science could very
easily be phenomenally conscious states, though clearly not the conscious
states of the subject in question. If this is possible, then we must rethink
the explanatory nature of appeals to such sub-personal cognition, since
evidently nothing explanatory is generated by the assumption that such
cognition is the subject’s own cognition. Furthermore, since plausibly the
phenomenally conscious states of some other subject could be misunderstood by
third-person observers, it is in principle possible that the content of
sub-personal cognitive activity is quite different than cognitive scientists
believe. But if this is possible, then it would seem that the attribution of
particular contents to sub-personal cognition is also explanatorily otiose.
Together, these points suggest that attributing sub-personal cognition to
certain regions of the brain is not in and of itself explanatory of anything.
The real explanatory work is instead accomplished simply by establishing
regular correlations between certain types of brain activity and certain types
of phenomenally conscious experience.
21. Can
there be a scientific explanation of consciousness without qualia?
Stephen R.
Deiss.
UC San Diego deiss@appliedneuro.com
ASSC is founded on the premise that the methods
of science are the proper approach to a true understanding of the nature of
consciousness. Science is rooted in
materialism and physicalism. Few would
question that human awareness supervenes on an intact brain. However, does it follow that all awareness
supervenes on an intact mammalian brain?
What about a starfish or a microbe?
This talk will be about a little acknowledged \"chicken and
egg\" problem. Which comes first -
qualitative conscious awareness or scientific observation? To answer that preliminary questions need to
be answered. What are qualia? What role do they play in consciousness
studies? What role should they play in
science? Should they be eliminated? I will argue that qualia are about neither
\'the redness of red\' nor \'what it is like.\'
Qualia are basically information theoretic having to do with detectable
differences. They are fundamental for
doing science. This also clarifies what
consciousness is as a process, including scientific observation in
particular. However, to fully appreciate
the role of qualia in science, we have to acknowledge and reexamine some of our
most basic presuppositions in science about mechanisms and laws. Mechanism is one of the most frequent words
heard at any scientific meeting.
Everyone is looking for them. But
what are they, and what necessity do they carry? I will argue that our mechanistic world is a
theoretical construct that results from how we habitually interpret qualitative
sensations. There are alternatives to be
considered. Conscious awareness as
defined here is epistemologically prior to scientific observation. The upshot is that science has is limitations
when practiced by individuals. Science
can transcend those epistemological limitations through consensus as it has all
along. However, consensus comes one
conscious observer at a time. As
Protagoras once said, “Man is the measure of all things.” While I would argue that this was a great
overstatement, qualia will always have their place enabling observation.
22. On
the selving self: a reappraisal of Kant’s theory of consciousness and James’
anti-Kantianism.
Paulo Jesus.
According to Kant, the
“I think” or the synthesising self-consciousness is the supreme act of
unification as well as the logical form of representation (Ameriks, 2000;
Kitcher, 1990, 2006; Sturma, 1985). Its distinctive feature consists in
«accompanying» (begleiten) necessarily all my representations, and thus it is
the possibility of inner sense or self-perception despite remaining irreducible
to it for the “I think” denotes a continuous unconscious cognitive activity, on
which relies not only the unification of my representations but also the
unification of my mental operations. Contemporary
theories of consciousness (e.g. Anscombe, Chalmers, Dennett, Dretske, Evans,
Gallagher, Kripke, McDowell, Sellars, Siewert, etc.) comprise four main
classes, that is, (1) higher-order theories explaining consciousness by means
of metacognition or meta-representations, (2) same-order theories holding the
hypothesis of self-(re)presenting states, (3) theories considering the
conscious character a mere representational correlate of all mental content,
and (4) zero-order theories describing phenomenal consciousness as pure
appearing without reflexivity nor representability (Kriegel & Williford,
2006). By confronting Kant with this framework, new questions arise about the
possibility of qualitative continuity in assigning a flux or stream of mental
events to Myself (James, 1890). In line with Kant’s Refutation of Idealism and
in accordance with contemporary sensitivity, one should also ask whether and to
what extent the mind is corporeal, given that the phenomenology of a unifying
time-consciousness convokes the phenomenology of a unifying space-consciousness
through the construction of a systemic unity of kinaesthetic intentions or
endeavours as embodied activity in the world (Berthoz & Petit, 2006). The
Self-Dynamics shows how accurately the motion of the mind responds to the
motion of the body, and how deeply (meta)cognition is pervaded by bodily
self-awareness and «ecological proprioception» (Merleau-Ponty, 1945; Damasio,
1995, 1999, 2003; Gallagher, 2006). This entails a final issue concerning the
relationship between intersubjective cognition and inter-corporality.
24. On
self-awareness and being an objective particular in an objective space and
time. Fauve Lybaert.
When I’m aware of being an I with a diachronic
existence, am I then necessarily referring to myself as being an objective
particular that is in principle traceable by others in an objective space and
time? To probe this question I evaluate
what Husserl says about the self-individuation and -unification of
consciousness in his Ideas II. He claims that there could be a consciousness
that individuates and unifies itself even if there were no nature. I conclude that Husserl’s view is untenable.
I raise questions that bring out how the constitution of our self-consciousness
depends on our capacity to situate ourselves in an objective space and time.
Two examples. (1) Isn’t it a phenomenon that I in consciousness feel that I’m
here, and does this not give my consciousness at least a ghostly body? (2)
Husserl demonstrates how Erlebnisse reorganize themselves. What first belonged
to the primal present becomes retained (but we can bring everything back to
mind in principle), and memories of the same event will never be the same
because they’ll be tied to a new context. But would these Erlebnisse reorganize
themselves in this way if we didn’t have the idea of being one person with one
particular history that stretches itself out through a time of days and years?
We seem to need the idea of a person and a linearly unfolding time to conceive
of the idea that we can trace back some of our experiences. Even when we
understand that the time in which our memory-contents are presented to us
doesn’t match the objective time, a question remains. When past experiences
come to mind, could this then be made possible by an awareness of the fact that
one has one diachronically unfolding life? Could this be necessary to motivate
us to turn to past experiences so as to make sense of current experiences? A
consequence for the question of personal identity would be that my one identity
is not so much constituted by the memories I have, as my memories may be
constituted by the one identity I have.
25. Self-consciousness
and anosognosia in Alzheimer's dementia.
Karen Yan.
Anosognosia refers to
a condition in which one lacks awareness or acknowledgment of one's own
syndrome. Patients diagnosed with Alzheimer's Dementia (AD) typically suffer
anosognosia, often leading to a thought that there is nothing wrong with them.
It is a heated debate on whether anosognosia in AD is a form of faulty
awareness or acknowledgment, but less attention has been paid to its relation
to self-consciousness. What is the structure of the experiential life in which
AD patients live and feel their own existence? How does it differ from
non-demented people? Could this explain anosognosia in AD and help settle the
debate? This paper aims to answer these questions by providing a model for
understanding self-consciousness in the context of anosognosia in AD.
Specifically, the model mechanistically differentiates three different senses
of self-consciousness: Pre-reflective, reflective and narrative; however, they
should be treated as three hierarchically nested "entities" or
"activities," integrating as a complex mechanism. Secondly, any
exposition of AD patients' sense of existence must incorporate how the three
interact and constrain each other. Finally, the temporal organization and
intersubjective dimension of the hierarchically nested self-consciousness help
explain why and how AD patients come to have anosognosia, whether it is faulty
awareness or acknowledgment.
26. Only time will tell: On the nature of free will.
Ken Mogi
Sony Computer Science Laboratories kenmogi@qualia-manifesto.com
The contingency between sensory inputs and motor
outputs is one of the crucial aspects of the neural mechanism underlying the
phenomenology of consciousness. For example, the nature of subjective time is
known to be affected by the contingency between voluntary action and sensory
feedback (Haggard et al. 2002). The perception of self body is affected by the
contingency between actions and sensory feedbacks, as demonstrated in the
mirror box treatment of phantom limbs (Ramachandran et al. 1995). Various
empirical evidences suggest that sensori-motor contingency affects the
construction of the phenomenal self in its temporal and embodied dimensions. One important and arguably ultimate question
regarding human consciousness is that of free will. The question concerning the
nature of free will is an essential one not only from theoretical point of view
but also from the social implications involved (e.g. from the point of view of
neuroethics, Gazzaniga 2005). In that free will concerns itself with the
movement of the body in time, it is necessary to consider its nature in the
context of sensori-motor contingency. From the phenomenological point of view,
neural processes involved in action can be regarded as a subset of those involved in intentional processes in
general. Here I argue that the nature
of free will can be properly treated only by taking subjective time into
consideration. Only a consideration of the nature of subjective time will tell
us the origin of the feeling of free will, when it is taken to be compatible
with determinism (Dennet 2003). I
present a model of subjective time based on the interaction between sensory and
intentional processes in the brain, in which two kinds of simultaneity
("sensory simultaneity" and "intentional simultaneity") are
defined. Using the model, I analyze the differential nature of neural circuits
involved in sensory and motor processes, based on the anatomical data on human
brain (e.g., Van Essen 2004). Finally, I give an account of the neural
correlates of free will in terms of the "open-ended" structures of
intentional simultaneity in subjective time, in the context of the topology of
connectivity in the cortical neural network.
27. Reflections
of the self: an fMRI investigation of links between animistic thought and
self-processing.
Monika Sobczak1,
Noam Sagiv1, and
1
The imbuing of objects and events with life and
consciousness has been studied in psychology under the term 'animism'. Almost a century ago, Piaget (1929) made the
conjecture that children's predisposition to display animistic modes of
thinking is induced by their tendency to construct reality with the self as a
model. To test this speculation empirically, we used functional magnetic
resonance imaging (fMRI) to determine whether processes implemented in
personification (a type of animistic thought) engage brain areas from the
self-referential neuronal network. Nine naïve subjects were presented with a
set of pictures of household objects. In half of these images one object was
shown separated from the rest (intended to trigger experience of the social
attribute of loneliness). Later the experiment was repeated after priming the
participants to imagine how the excluded objects might feel. We demonstrate that brain areas associated
with self-referential structures such as the insula, the precuneus, the
inferior frontal cortex, the posterior cingulate, together with the temporal-parietal junction,
the fusiform gyrus, and the lingual gyrus (brain regions linked with
mentalising) are implementing processes involved in animistic thought. This supports the
Piagetian conjecture that our social cognition is filtered through self-related
concepts and experiences. Furthermore, the precuneus, temporo-parietal
junction, and the posterior cingulate were also activated before priming (when
participants had not considered a possible social interpretation of the
stimuli). This suggests that personification may be an automatic,
pre-reflective process.
28.
Quantifying the richness of phenomenal experience.
Tomer Fekete1
and Shimon Edelman2.
1 Stony
brook university Tomer.Fekete@mail.huji.ac.il
2
Cornell University
As arousal waxes and wanes, the richness of our
experience varies profoundly from the near oblivion of dreamless sleep to the
exquisite detail of full alertness. What systematic changes in the underlying
brain activity bring about such changes in experience? We propose that the
representational capacity of the underlying brain machinery – the degree to
which the dynamics of a system is fit to embody information – is the delimiting
factor in realizing phenomenal content.
From the standpoint of implementation, the richness of experience must
be provided for in the complexity of the structure of brain activity, which is
the vehicle of experience. From the functional standpoint, the richness of
experience supervenes on the ability to draw increasingly refined distinctions
concerning the environment and the content of experience itself. These
observations entail that the structure of the underlying neuronal activity
space should match in its complexity the myriad of relations among the contents
of experience. Thus, we define the representational capacity of a neuronal
activity space in terms of the coupling between the complexity of its structure
and the complexity of the activity it admits.
If the richness of experience is to covary with arousal, it must remain
unchanged if arousal is fixed at a given level. As it is the complexity of
activity that sustains the richness of experience, this means that in a given
state of arousal the complexity of activity is fixed as well. This suggests
that representational capacity can be estimated by fitting an indicator
function (classifier) parameterized by arousal to neuronal data, then using it
to reconstruct the underlying neuronal activity spaces via the level set
method. The complexity of the arousal-dependent activity spaces can now be
estimated by computing their multi-scale homology, which measures not only the
degree to which activity is inherently clustered but also the effective
dimensionality of the configurations formed by the clusters. This approach to quantifying
representational capacity was successfully applied to primate imaging data
(Fekete et al., 2009). Our present research highlights its relevance to the
development of a computational theory of phenomenal experience.
29. Kant's
theory of consciousness and self-representationalism.
Jerry Yang.
National Taipei University of Technology jyang@ntut.edu.tw
The paper investigates whether
Self-representationalism can be rooted in Kant’s theory of consciousness. According to Self-representationalism, one’s
mental state does not only represent an object in the world, it can also
represent one to oneself as the subject of that state. In his article “Kant: A Unified
Representational Base for All Consciousness” (2006) and forthcoming book,
co-authored with Paul Raymont, A Unified
Theory of Consciousness (MIT Press), Brook suggests that Kant’s theory of
consciousness, anchored in the conception of transcendental apperception(TA),
can provide an account of Self-representing representations that supports
Self-representationlism. Following
Strawson’s steps in Bounds of Sense (1966),which implicitly maintains that for
Kant’s theory of consciousness to
succeed, an empirical reference “I” for each subject of experience is required,
I point out that Kant’s original account cannot complete the task as Brook
hopes. For the consciousness performed
by TA lacks the empirical reference of the personal pronouns “I” for each
subject of experience due to the fact that TA can only represent the manifold
of representations in Kant’s original design.
In other words, TA cannot self-represent, meaning, representing one to
oneself so that one would know one is the subject of experience. I argue that there is a distinction between
the thematic activity and non-thematic activity for the operations of TA. The former is to represent the manifold
representations; the latter, on the other hand, is to self-represent. For the distinction to work, however, one has
to treat Kant’s idea of “the self” as something single and complete with two
kinds of properties, i.e. as a subject that has both empirical properties and
transcendental ones, not a logical function “I” as some Kant scholars
suggested. The paper shall explore
scientific evidence in relating to the distinction in question. The thematic activity and the non-thematic
activity have different but complementary abilities of TA. By making the above-mentioned distinction, we
could know not only the nature of human cognition better, we may picture a
scenario in which Self-representationalism can be contingent upon Kant’s theory
of consciousness as well.
30.
Deferential phenomenal concepts? Not for the zombie Mary.
Lynn
C.H. Chiu.
University of Missouri-Columbia ccf79@mail.missouri.edu
The Knowledge Argument
(KA) against physicalism relies on the intuition that without undergoing
experiences, one cannot gain knowledge of their phenomenal characters, i.e.
“what it is like” to undergo the experiences. Even with complete physical
knowledge, Mary, the super-scientist, would still gain new knowledge when she
experiences red for the first time. Phenomenal concept strategists
counter-argue that Mary's new knowledge is constituted by new concepts
referring to things she already knows, special concepts that are gained only
when one undergoes phenomenal experience. Tye (2009) denies that there are such
concepts. He argues that concepts about the phenomenal character of an
experience are deferential, and since one can partially understand a
deferential concept and one possesses a concept when it is partially
understood, one can possess the concept without experience. I will argue that
Tye’s understanding of deferential concepts implies that one can partially
understand a concept C without the relevant experiences only if one already
possesses a more general categorical concept CC under which referents of C also
fall. Thus, for one to possess a phenomenal concept PC prior to experience, one
has to at least possess one particular non-deferential categorical phenomenal
concept—the CC that this is a phenomenal character—which in turn, I shall argue,
can be gained only via experience. That is, only if Mary has conceptualized her
other experiences as phenomenal would Tye's conclusion follow, that she could
possess PCs of new experiences. I've shown that Tye's argument rests on the
assumption that Mary-in-the-room is not a philosophical zombie, however, Tye's,
nor others' reconstructions of KA require this aspect of Mary. KA is
traditionally thought to work with only premises about her complete knowledge,
the first experience of red and our intuitions. Thus, this study shows that
either KA should specify that Mary has to have other experiences prior to the
new one or Tye's argument against the strategists only work against the
versions that do. If the former, the effect of
other experiences would affect counterarguments that employ Mary the
ability to imagine new experiences a prior.
31. Consciousness,
access and phenomenal overflow: a reply to Block.
T. Bradley
Richards.
Ned
Block claims that phenomenology "overflows" cognitive accessibility,
that the capacity of phenomenal experience is greater than the capacity of the
‘global workspace’, and thus, that there are conscious experiences that are
inaccessible. He thinks overflow is the best explanation of certain
experimental results (e.g., Sperling (1960); Landman et.al., (2003)).
Phenomenal overflow is only a good explanation of the experimental results if
the subjects in these experiments have specific (as opposed to generic)
phenomenal contents of the relevant kind for all or most of the items presented
prior to the cue. Block must distinguish between two kinds of access in order
for his view to be intelligible, but once he has done so, he cannot use
subjects’ reports as evidence of specific phenomenology in the phenomenal
overflow experiments: this would require subjects to both have and not have
*cognitive* access to a content C at t. This leaves Block with only neural
evidence, and at least current neural evidence does not support the claim that
subjects have specific phenomenology of the relevant kind. Given that there is
no evidence that the subjects have specific phenomenology, phenomenal overflow
is not even a good explanation of the experimental results. While these
considerations do not show that there are no inaccessible phenomenal states,
they do show that we have no reason to posit them. Further, if there were
inaccessible phenomenal states, it would be impossible to specify phenomenal
contents of any kind. Thus, if phenomenal contents or the theories that employ
them are of any value, we have a reason not to posit inaccessible phenomenal
contents. Finally, I speculate that Block’s original claim that phenomenology
overflows accessibility would be vindicated if there was contentless phenomenal
experience. This would account for our intuition that infants and certain kinds
of animals can be conscious despite lacking the capacity for certain kinds of
higher order thought, and broadcasting to the global workspace (and a global
workspace). It would also account for correlates of phenomenal consciousness
that are not broadcast, if there are any, without requiring inaccessible
phenomenal contents.
32.
Do dementia patients lose their self?
Lin
Ying-Tung1 and Allen Y. Houng2.
1 Johannes-Gutenberg-Universität
Mainz jo.yt.lin@gmail.com
2 National
Yang-Ming University
Dementia patients with the loss of some brain
functions have altered consciousness. At their later stages, most patients
cannot recognize their families or close friends and hold a story about
themselves that is totally contradictory to what they really are. Due to their
confabulation, dementia patients are often regarded as having no self. I argue
here that dementia patients still have a self. First, I will introduce two
concepts of self—the minimal self and the narrative self. The minimal self is
the consciousness of oneself as an immediate subject of experience, unextended
in time, which provides a point of view for experiencing and a framework for
one’s autobiography. The narrative self includes memories of the past and
intentions toward the future to extend in time. With this distinction, I argue
that dementia patients have both the minimal self and the narrative self, and
the difference between healthy people and dementia patients is that healthy
people can maintain one consistent story within a long period of time, while
the dementia patients, due to the malfunction of their memory, cannot maintain
their own autobiography. In addition, these patients make up stories about
themselves all the time, in order to compensate their memories that are unable
to be recalled. Whether the dementia patients have self or not is an important
issue, which relates to many practical decisions such as whether they have
moral or legal responsibilities or how they should be treated. Since dementia
patients do have a self, we should reconsider these ethical issues.
33. The
context of stimulus association influences the perception of visual similarity.
Jae-Jin Ryu1
and Thomas Albright1.
1 Systems
Neurobiology Laboratories, The Salk Institute for Biological Studies jjryu@salk.edu
The ability to discriminate stimuli that are
perceptually similar to one another is crucial for identification and
categorization of visual inputs. Multiple lines of evidence suggest that
processing of visual inputs is amenable to top-down influences stemming from
prior experience and knowledge. These previous findings lead to the suggestion
that the perception of visual similarity is also susceptible to the memory of
prior experience. Here, we investigated whether the context of previous
stimulus association has an impact on the perception of stimulus similarity. In
the present study, we introduced two different contexts in which two visual
stimuli with slightly different orientations were each associated with an
auditory stimulus. The nature of the associative context was determined by the
relative degree of similarity between the two auditory stimuli: in the
Divergent context, the difference in the frequency of the auditory stimuli was
800 Hz, whereas the difference between the auditory stimuli was 3 Hz in the
Convergent context. The angular difference between the visual stimuli was
constant across the two conditions. The measure of discrimination (D’) of the
two visual stimuli was significantly increased following the acquisition of the
visual-auditory association in the Divergent context. However, no major increase
in D’ was found in the Convergent context. In order to determine the
specificity of the observed changes in perceived similarity, we measured the
discrimination performance of orientations that were adjacent to the two
orientations presented during the visual-auditory association in a subsequent
experiment. Again, the pattern of changes in discrimination of the nearby
orientations was consistent with the context of the stimulus associations: In
the Divergent context, learning of the stimulus association significantly
improved discrimination of nearby orientations, whereas the context of the
stimulus association in the Convergent condition resulted in a decrease in the
discrimination performance. Together, our results suggest that the context of
previous stimulus association can alter perceived similarity of basic visual
stimuli, and that the observed changes are accompanied by overall changes in
the perceptual space representing these stimuli in the visual cortex.
34. Masked
primes activate the frontal-parietal control system independent from prime
visibility.
Susan Klapötke1,
Daniel Krüger1, and Uwe Mattler1.
1 Institute for
Psychology Göttingen smeissn@uni-goettingen.de
The cognitive control system is traditionally
related to conscious processes. Previous research has shown, however, that
unconscious visual stimuli can affect mental operations that are necessary to
perform a discrimination task. Using functional magnetic resonance imaging, we
investigated whether masked primes can access the frontal-parietal control
system. Participants responded to visual target stimuli made of a human face
and a superimposed scene in a speeded choice response task. A cue validly indicated
whether they had to respond to the face (man vs. woman) or to the scene (indoor
vs. outdoor) of the picture. In addition, the cue served as a metacontrast mask
for a preceding prime which was either congruent or incongruent to the cue. On
congruent trials participants responded faster than on incongruent trials. This
behavioral priming effect did not depend on conscious perception of the
effective stimulus because it was larger when prime visibility was reduced.
Activity of parietal and frontal regions was increased on incongruent as
compared to congruent trials. Importantly, this neuronal priming effect was
especially pronounced when prime visibility was low. These results suggest that
the cognitive control system is sensitive to visual stimuli irrespective of
conscious awareness of these stimuli.
35. Unconscious
visual stimuli modulate endogenous orienting of covert spatial attention.
Simon Palmer1 and Uwe Mattler1.
1 University
of Göttingen simon.palmer@psych.uni-goettingen.de
Subliminal stimuli can affect exogenous shifts of
spatial attention, whereas endogenous orienting of attention is typically
thought to require executive control. In this study we investigated effects of
masked visual stimuli in an endogenous orienting task. Primes were followed by
congruent or incongruent cues which served as metacontrast-masks for the prime.
Cues validly indicated the position of subsequent targets. Subjects classified
targets faster when prime and cue were congruent than when they were
incongruent. This priming effect increased when the time between prime and cue
increased, but it decreased when the time between cue and target increased.
Additional research showed that this priming effect cannot be reduced to an
effect of the perceptual similarity between prime and cue. Eye movements were
controlled to rule out any occulomotor contribution to the priming effects.
Results show that unconscious visual stimuli can modulate endogenous orienting
of attention. Presumably, unconscious primes can initiate shifts of spatial
attention if they share critical features with the cues. This finding
contributes to the distinction between processes related to attention and
consciousness.
36. How
features of the mask modulate inverse priming effects of unconscious visual
stimuli.
Daniel Krüger1
and Uwe Mattler1.
1 Institute
for Psychology, University Göttingen dkruege@uni-goettingen.de
An
affirmative answer to the question whether there is a qualitative difference
between conscious and unconscious processing has been suggested in recently by
a counterintuitive phenomenon called “negative compatibility effect” or
“inverse priming effect”. This effect results when a prime stimulus is followed
by a mask and a subsequent target stimulus. It consists in slow and frequently
incorrect responses when prime and target stimuli are congruent, and fast and
accurate responses on incongruent trials. The magnitude of this effect is modulated
by the structure of the mask: If the mask contains features of alternative
target stimuli (relevant masks) the effect is larger than if it contains
irrelevant features (irrelevant masks). However, the crucial features of
task-relevant masks are unclear. Here we varied the structure of the mask in
four levels between “irrelevant” and “relevant”. Instead of a gradual increase
of the effect, we found the same effect for three variants of irrelevant masks
and increased effects with a clearly relevant mask, which consisted of a
superimposition of the two prime/target alternatives. With such a relevant
mask, the size of inverse priming effects was the same irrespective of prime
visibility. With all other masks, however, inverse priming occurred only in those
subjects who were unable to recognize the primes. These findings suggest two
independent mechanisms which generate inverse priming effects: one mechanism
operates independent of prime visibility with relevant masks, whereas another
mechanism operates only when the effective stimuli remain unconscious.
37.
The origins of synaesthesia: a direct comparison of pitch–luminance mapping
in chimpanzees and humans.
Vera Ludwig1,
Ikuma Adachi2, and Tetsuro Matsuzawa2.
1 Berlin
Charité vera.ludwig@hu-berlin.de
2
Primate Research Institute,
In synaesthesia, input to one sensory modality
leads to automatic and vivid secondary experiences. For example, sound–colour
synaesthetes see colours when they hear sounds. Also non-synaesthetes
experience synaesthesia-like correspondences to some extent, albeit more
implicitly. Most prominently, humans – already as toddlers – associate high
pitch sounds with light colours and low pitch sounds with dark colours. Sound–colour
synaesthetes map in the same direction. It has been proposed that
synaesthesia-like correspondences – such as pitch–luminance mapping – are
innate rather than learned, and that they might have been a driving factor in
the evolution of language. If this is true, they might have co-evolved with
language late in evolutionary history and hence might exist uniquely in humans.
Alternatively, they might have evolved earlier, either due to a function
unrelated to language or as a by-product of the primate sensory system. To pin
down the evolutionary origins of synaesthesia, cross-species comparisons are
vital. However, so far no study has addressed the question whether non-human
animals experience synaesthesia-like correspondences. Here we provide the first
direct comparison between chimpanzees and humans concerning the mapping of high
pitch to high luminance and of low pitch to low luminance. Participants from
both species were required to classify squares as black or white while hearing
irrelevant background sounds that were either high-pitched or low-pitched.
Chimpanzees made more mistakes when the background sound was synaesthetically
incongruent (low-pitched for white, high-pitched for black) than when it was
synaesthetically congruent (high-pitched for white, low-pitched for black). In
humans, the effect was evident through increased latencies in incongruent
trials in line with previous research. These results suggest that the two
species share pitch–luminance mappings and possibly other synaesthesia-like
correspondences. Synaesthesia in humans hence partly reflects evolutionary old
mechanisms in the primate brain.
38. What
Synaesthesia may tell us about the unity of consciousness.
Aleksandra
Mroczko1 and Thomas Metzinger2.
1 Department
of Philosophy, The University of Mainz mroczka@uni-mainz.de
2 Department
of Philosophy, Johannes Gutenberg-University
The phenomenon of synaesthesia, in which a
multitude of experiential levels is integrated under a unified phenomenal
perspective, poses many pressing questions for multidisciplinary approaches to
consciousness and cognition. However, its relevance and explanatory potential
for theories of consciousness has not been fully realized in philosophy of
mind. A related target phenomenon is
the synchronic unity of consciousness. Sometimes it has evoked skepticism in
the scientific study of consciousness. Especially in certain pathological
states like: split-brain syndrome or DID, this unity has been claimed to be
broken down (Nagel 1971, Dennett 1992). Nevertheless, such an apparent breach
may only be one extreme on the continuum of the unity of consciousness. The
continuum embraces various forms of unity, e.g. access, phenomenal, subject,
object and spatial, which, depending on the neuropsychological condition,
produce different degrees of coherence in unifying selected conscious states.
This continuum should be understood as the domain of a qualitative universal
(experiential coherence) – a general phenomenal property, instantiated and
differentiated by particular conditions from neuropsychopathology, normal and
extraordinary perception. In such a pluralistic framework for the unity of
consciousness, the phenomenon of synaesthesia mirrors the other side of the continuum,
where conscious experiences seem to be hypercoherent, i.e. more strongly
unified than in ordinary situation, especially in the case of projectors
binding perceptually a concurrent feature to its inducer (Dixon et al. 2004).
Therefore, synaesthesia seems to be one of the best model phenomena to compare
the varying distribution of phenomenal coherence between different
neuropsychological phenomena.
Neurophysiological mechanisms of binding, attention and multimodal
integration associated with the relevant phenomenological feature of
synaesthesia (Singer & Gray 1995; Treisman 1998, 2005), are posed here
against the background on the traditional conceptual issues involved in a
philosophical understanding the unity of consciousness, with the conclusion that
the universal property of being unified, or experiential coherence for
conscious states actually exists, but can only be empirically observed at its
concrete psychological instantiation. The aim of the proposal is to argue for
the thesis that the phenomenal unity of consciousness can be seen as a highly
specific functional, therefore multirealizable, but also graded, feature.
39. Synaesthesia
helps understanding consciousness: Concepts may be made of qualia.
Danko Nikolic.
Max-Planck Institute for Brain Research, Frankfurt
Institute for Advanced Studies danko.nikolic@gmail.com
Traditionally, we think of qualia differently than
of concepts. The first phenomenon is about concrete perceptual experiences. The
second one appears abstract; void of such sensations. But research on
synaesthesia suggests another view. Recently, we learned that, in synaesthesia,
concepts, rather than sensory inputs, activate perceptual experiences rich in
qualia. For example, it is the concept of letter \"A\" that evokes
perception-like experience of say, a red color. The classical, low-level view
of synaesthesia, as cross-wiring between senses, is being abandoned on
empirical grounds. The new insight into
synaesthesia offers new implications for understanding the functional role of
phenomenal conscious experiences. If, in synaesthesia, a quale is a part of a
concept, in non-synaesthesia a similar close relation may exist; Concepts may
be made of qualia. Traditionally, qualia
are assigned to lower levels of sensory processing, i.e., the inputs. The
assumption is that the presence of qualia is driven by the presence of physical
inputs and that this sensory processing operates at a different level than the
conceptual one. The new view, springing from the synaesthesia research,
suggests that sensation and conception operate at the same processing
level. In fact, the two may be
inseparably intertwined. The simplest qualia, those evoked by pure colors or
sounds, may define elementary concepts--blocks off which more complex ones are
built. Thus, merger and rearrangement of the existing qualia (existing
concepts) may be the process of constructing the new concepts (new
qualia)--combining a red and a blue into purple; vanilla and sugar into a taste
of a cake; a sequence of tones into a melody; social experiences into a concept
of freedom. Our entire explicit
knowledge and its cognitive manipulation may not be possible to detach from its
fundamental phenomenal bases. Within the network of knowledge, activation of
any concept may be tied to activation of private feelings and sensations--as it
occurs so vividly, and in an exaggerated, empirically testable way, in
synaesthesia. Phenomenal sensation may be the means of cognitive association.
Qualia, rather than concepts, may be the main operational substrate of our
semantical thinking minds.
40. An fMRI study of auditory figure-ground segregation.
Sundeep Teki 1,
, Maria Chait 1; Sukhbinder Kumar 1 , and Timothy
D. Griffiths 1
1 Auditory Research Group,
Figure-ground
segregation – the process by which the brain extracts certain coherent patterns
from a mixture of other patterns, is a fundamental aspect of scene
analysis. So far, the investigation of
these processes in the auditory modality has been limited by use of ‘figure’
and ‘background’ stimuli that are physically different (e.g. a tone in noise).
In the present functional magnetic resonance imaging (fMRI) study we employ a
new paradigm, similar to Julesz‘s visual pattern discrimination paradigm
(Julesz, 1962) by which the figure and background span the same spectral space
but differ in the statistics of fluctuation, allowing us to reliably identify
brain areas that play a role in figure/ground segregation per se as opposed to those activated by different characteristic
properties of sound.
Stimuli consisted of a sequence of 50 ms
long chords containing a random set of pure tone components with frequencies
ranging from 179 to 7246 Hz. This results in the percept of random tonal noise.
Occasionally, a subset of tonal components repeated in frequency over several
consecutive chords, resulting in the percept of a ‘figure’ popping out of the
random noise. The duration of this repeating pattern and the number of fixed
components (we refer to his as ‘the coherence of the figure’) were varied as
parameters. To extract the figure, the brain must perform simultaneous (over
different frequency components) and sequential (over time) grouping. Indeed,
behavioral results demonstrate that listeners are remarkably sensitive to the
emergence of such figures. In the scanner we presented listeners with figures
constructed with parameters that span the behavioral detection range (from not-
to highly- detectable) in order to identify the brain areas whose activity is
correlated with increasing figure duration and/or coherence.
The study consisted of a passive and an
active paradigm. In the passive study, subjects listened to the sound stimuli
consisting of figures but were instructed to respond to unrelated decoy
stimuli. Thereafter, the same subjects were trained and instructed to respond
actively to the figures in the stimuli by pressing a keypad. The stimuli were
presented in a continuous
scanning paradigm in a 3T MRI scanner.
Previous studies suggested that auditory
cortex plays a major role in figure ground segregation. Here we show that
activity in the intraparietal sulcus (IPS), beyond the auditory cortex, is
correlated with the perception of such auditory figures. These findings stand
in good agreement with the reported role of IPS in auditory stream segregation
(Cusack, 2005). IPS has also been implicated in binding in vision, touch and
cross-modally suggesting it has a general role in perceptual binding and
structuring sensory input.
41. Unconscious
semantic and repetition priming in the auditory modality.
Jérôme Daltrozzo1,
Carine Signoret1, Barbara Tillmann1, and Fabien Perrin1.
1 CNRS
UCBL UMR5020 fperrin@recherche.univ-lyon1.fr
Unconscious
word priming has mostly been reported in the visual domain. With auditory
stimulation, only one study has reported a repetition priming effect using
distorted (time compressed) words. In the present study, pairs of words
(semantically unrelated, related, or repeated) were randomly presented to
adults who performed a lexical decision task (LDT). The participant's level of
awareness of the prime was assessed with a categorization task showing close to
chance performance (d'=0.10). Semantic and repetition priming were found in a
sub-sample of the slowest participants at the LDT. The repetition priming was
negative: a faster response to related compared to repeated pairs. This report
is the first of unconscious semantic priming in the auditory modality.
Furthermore, we were also able to show for the first time an unconscious
auditory repetition priming with prime words that were not distorted.
42. Electrical
brain dissociation for consciously and unconsciously categorized auditory
stimuli.
Carine Signoret1,
Etienne Gaudrain2, and Fabien Perrin3.
1 UCBL - CNRS UMR 5020 Lyon France
2 MRC
Cognition and Brain Sciences
3 CNRS
UCBL UMR5020 fperrin@recherche.univ-lyon1.fr
While a large number of studies have investigated
the neural correlates of visual conscious perception, little is known about
auditory conscious perception. In the present study, we have investigated the
electroencephalographic (evoked and induced) responses to behaviorally
categorized or uncategorized words, pseudo-words and sounds, and to silences.
Results suggest that, like silences, uncategorized stimuli were not perceived :
none of the two evoked potentials nor induced theta activity. Interestingly,
uncategorized stimuli also shared neural mechanisms with those associated with
consciously categorized stimuli, notably a decrease in the beta band, thus
suggesting that uncategorized stimuli were partially processed. Hemispheric
differences in the beta band between words and non-lexical sounds (pseudo-words
and complex sounds), both for categorized and uncategorized stimuli, confirm
that, while stimuli were behaviorally uncategorized they were unconsciously
processed, probably at a lexical level.
43. Conscious
and unconscious spatial frequency processing during facial gender
categorization.
Verena
Willenbockel1, Benoit A. Bacon2, Éric McCabe1,
and Frédéric Gosselin1.
1 Université de Montréal verena.vw@gmail.com
2
Bishop's University
It is generally agreed that some aspects of a
visual scene are perceived consciously while others are perceived
unconsciously. However, it is not yet known precisely which information is
processed under different degrees of awareness in the adult human brain. Here,
we address this question in the spatial frequency (SF) domain using the SF
Bubbles technique (Gosselin & Schyns, 2001; Willenbockel et al., 2010) and
a masked repetition priming paradigm similar to that employed by Dehaene et al.
(2001). A “visible prime” condition was created by presenting the stimulus
sequence mask-blank-prime-blank-mask-target (prime, blank, and mask durations
<= 50 ms) and an “invisible prime” condition by reversing the temporal order
of the masks and the blanks. Twenty grayscale face photographs (10 males)
served as primes and as targets, and the primes were randomly SF sampled
trial-by-trial. 12 observers were instructed to identify the gender of the
target face accurately and as fast as possible over 25 blocks of 40 trials per
condition. Our results revealed effects of SF filtering on observers’ response
times for both conditions, confirming that conscious and unconscious priming
occurred. A multiple linear regression was run on the filtering profiles and
response times to obtain classification vectors: The classification vector for
the visible prime condition peaked at 11.7 cycles per face width (cpf), revealing
a significant SF range of 1.6 octaves (p < .05, Sr = 256, FWHM = 4.24, Zcrit
= 2.7; see Chauvin et al., 2005). The classification vector for the invisible
prime condition showed a pronounced dip within this SF range (significant for
blocks 5-25). The difference reached significance for an SF range of 0.7
octaves, with a maximum Z-score at 11.2 cpf. No other SFs were significant. Our
results suggest that the diagnostic SFs for conscious facial gender
categorization (as well as conscious face identification; see Willenbockel et
al., 2010) are suppressed relative to the other SFs during unconscious facial
gender categorization. Possibly, many SFs prime to a small extent in the
unconscious condition, whereas a more precisely defined, narrow SF range primes
in the conscious condition, where top-down influences play a greater role.
44. The
objects behind the scenes: TMS to area LO disrupts object but not scene
categorization.
Caitlin Mullin1,
Krista Kelly1, and Jennifer Steeves1.
1
Many
influential theories of scene perception are object centered (Biederman, 1981)
suggesting that scenes are processed by extension of object processing in a
bottom-up fashion. However, an alternative approach to scene processing is that
the global gist of a scene can be processed in a top-down manner without the
need for first identifying its component objects (Oliva & Torralba, 2001).
This suggests that global aspects of a scene may be processed prior to (or
perhaps in parallel with) the identification of individual objects. Evidence
from a patient with visual object agnosia and bilateral damage to lateral
occipital (LO) cortex, an area associated with object processing (Grill-Spector
et al., 2001), also suggests that scene categorization can operate
independently of object perception (Steeves et al., 2004). Objectives: To
determine whether temporary interruption to area LO in neurologically-intact
controls with repetitive transcranial magnetic stimulation (rTMS) impairs
object and scene processing. Materials and Methods: In an offline pre-post
design, participants categorized greyscale images of objects and scenes as
'natural' or 'man-made'. Images were displayed for 100ms followed immediately
by a mask which remained onscreen until participants responded. Subsequently,
we stereotaxically targeted area LO, which had been functionally defined with
fMRI, and participants underwent five minutes of rTMS. Immediately following
rTMS, they completed another version of the object and scene categorization
task. Test versions were counterbalanced across participants. Results: rTMS to
area LO reduced accuracy of object but not scene categorization. Surprisingly,
there was a trend for an improvement in scene categorization post rTMS. Conclusion:
These findings demonstrate that the global gist used to rapidly categorize
scenes remains intact despite an interruption to object processing brain
regions. This suggests that scenes can be processed independently of objects
and that these processes are not strictly hierarchical but rather they are
dissociable. Further, the temporary suppression of object processing may
actually facilitate scene processing, perhaps due to a release of inhibition.
45. Preserved
grip scaling for immediate but not delayed grasping in the absence of conscious
vision. Christopher Striemer1, Robert L. Whitwell1,
and Melvyn A. Goodale1.
1 University of Western
When we reach out to grasp an object our grip
automatically scales to the object’s size. Previous work has shown that DF – a
patient with visual form agnosia resulting from lesions to the ventro-lateral
occipital cortex – can still accurately grasp objects even though she cannot
discriminate between them on the basis of their shape. This suggests that the
visual pathways mediating visuomotor control in her spared dorsal stream can
operate independently from visual pathways controlling object recognition in her
damaged ventral stream. Importantly, although DF can scale her grip to objects
despite her inability to ‘see’ their shape, she still has access to several
other aspects of conscious vision (e.g., colour and luminance). In the present
study, we examined whether any conscious visual input from the ventral stream
is necessary for grasping objects in SJ – a patient who has a complete right
visual field hemianopia following damage to the left occipital cortex. We asked
SJ to reach out and grasp objects of different sizes presented entirely within
her sighted (left) or blind (right) visual field. In one experiment, SJ
demonstrated a remarkable ability to scale her grip to the size of objects in
both her sighted and her blind field. Although she was able to estimate the
size of the same objects when they were presented in her sighted field, she was
unable to do so in her blind field. In an additional experiment we demonstrated
that SJ’s ability to scale her grip to objects in her blind field was
completely abolished when a short 2-s delay (without vision) was introduced
just prior to reach onset. Critically, she was still able to scale her grip to
objects in her sighted field following the same 2-s delay. These results
suggest that when the visuomotor system operates in real time it does not
require conscious vision in order to scale the grasp to the size of the target
object. Only in delay, where a visual memory of the object seen moments before
needs to be accessed, is conscious vision critical.
46. The
effect of familiar size on simple reaction times.
Irene Sperandio1
and Melvyn A. Goodale1.
1
University of Western
It is usually reported that simple reaction time
(RT) decreases as stimulus size increases. Recent studies have shown that this
effect reflects perceived rather than retinal image size. Given this
relationship between simple RT and perception, one wonders if RTs are affected
by knowledge about object size. It is known that past experience provides
important information about the size of an object and helps with judgments of
size, but the effect on RT is unknown. We
carried out two experiments: one with a training procedure designed to induce a
strong association between colour and shape of a target and its physical size,
the other with a presentation of familiar objects of known size. By presenting
the objects with the same retinal size, it was possible to study the role of
familiar size in speeded motor responses. We found that only in the second
experiment were RTs affected by knowledge – but in an opposite way from what we
expected. Objects known to be smaller were responded to faster than objects
known to be larger (and vice versa). An analysis of perceptual judgments
revealed a misperception of size: the images of smaller familiar objects were
perceived as bigger than the images of larger familiar objects. A possible
explanation of this result is the size-distance invariance hypothesis (SDIH).
The SDIH argues that objects appear both as larger and nearer, or smaller and
further. In the perception of size and distance, like in many other aspects of
perception, observers are unaware which cues are being used to generate
conscious experience. Given that the actual retinal size is not normally
accessible to consciousness and that there are size constancy operations that
take place at preconscious levels of processing, it is plausible that smaller
objects that subtended the same retinal image size as larger objects are perceived
as closer hence appear bigger. These
results show that long- but not short-term familiarity affects RT, and that
size-distance relations are processed in an invariant manner such that any
misperception of distance necessarily involves a misperception of size and vice
versa.
47. Embodiment
of positive and negative emotions does not affect visual spatial attention
differently.
Shiau-Hua Liu1
and Li-shin Jhang1.
1
Department of Counselling and Clinical Psychology,
Emotions
can affect cognitive performance in many tasks (Fredrickson, 2001; Levine and
Burgess, 1997). Attention-plus-external-noise paradigm (Dosher & Lu, 2000)
has been developed and employed to investigate the mechanisms of visual spatial
attention and to quantify the attention effect size. Does the embodiment of
positive and negative emotions affect visual cued attention differently? This
study aims to quantify the embodiment effect of positive and negative emotions
by visual spatial attention paradigm. Participants were asked to hold a
chopstick between the teeth to create the embodiment of positive emotion and
between the lips to negative emotion. In the formal experiments, 3 observers
were asked to make 2-Alternative-Forced-Choice orientation judgments on
oriented Gabor patches. The experiment design varied 7 contrast levels, 2
cueing conditions (5/8 valid & 3/8 invalid central cueing), 2 noise
conditions, and 4 locations, which allowed fitting psychometric function curves
for each observer. Each session consisted of two sub-sessions and each
sub-session had 448 trials. Every observer participated in 5 experimental
sessions. The first session was for practice and then discarded. The results
showed the visual cued attention effect occurred for the embodiment of both
positive and negative emotions in high noise conditions, but not in no-noise
conditions. This confirmed that the major mechanism of visual spatial attention
was external noise exclusion. The visual spatial attention effect did not
differ between the embodiment of positive emotion and that of negative
emotions.
48. Gender differences in
estimation of affective pictures.
Osvaldas
Ruksenas1, Laura Maciukaite1, and Ramune Griksiene1.
Despite extensive investigation and increasing
interest in gender differences of cognitive abilities and emotional processing,
more questions than answers still remain. There is accumulating data that sex
steroid hormones have strong effect on functioning of central nervous system.
However, data concerning effects of these hormones on emotional processing in
both genders and during different phases of women menstrual cycle are scarce
and contradictory. The aim of our study
was to investigate how gender and phase of menstrual cycle influence evaluation
of affective pictures. Thirty university students (12 men and 18 women) 23,1 ±
2,4 years participated in this study. Thirty six images were selected from
International affective picture system (IAPS) and grouped into four sets of
nine photographs: three attractive, three neutral, three antipathetic. All
subjects participated in four experimental sessions. Women were investigated
during follicular, ovulatory, luteal and late luteal phases of menstrual cycle
confirmed by salivary 17β-estradiol and progesterone assessment.
Intervals between men experimental sessions correspond to women inter-session intervals
determined by phases. The task for subjects was to rate pictures in valence and
arousal dimensions using Self-Assessment Manikin instrument. Study revealed that estimation of affective
pictures differs between men and women. Rating of affective images by men is
stabile and independent of experimental day. Women rate pictures depending on
the phases of menstrual cycle. Attractive pictures were rated as the most
pleasant and arousing (statistically significant differences as compared to
other phases and men) during ovulatory (high 17β-estradiol) phase.
Rating of antipathetic pictures was less dependant on phase of menstrual cycle
and in all cases (except luteal, high progesterone, phase) these pictures were
rated as less pleasant and more arousing as compared to men. There is no published data about use of
International affective picture system for research in
49. Idiosyncratic
spatial inhomogeneities in breakthrough to consciousness of suppressed visual
stimuli.
Eric A. Reavis1,
Nicholas Root1, Peter Kohler1, and Peter Tse1.
1
Conscious experience incorporates only a portion of
the information available to the visual system. A step toward understanding
consciousness would be an improved understanding of the mechanisms whereby
certain information becomes conscious while other information does not. Several
stimulus presentation paradigms strongly bias the visual system toward
awareness of some information and unawareness of other simultaneously available
information. One such paradigm, continuous flash suppression (CFS), utilizes
dynamic, high-contrast Mondrian patterns flashed sequentially to one eye while
a static image is presented to the other eye. CFS presentation can render the
static image perceptually invisible for long periods of time (Tsuchiya and
Koch, 2005). The static, suppressed stimuli do sometimes overcome suppression,
however, and they are then incorporated into conscious percepts. We demonstrate
that the probability of CFS-suppressed stimuli becoming conscious varies
substantially by location in the visual field. Method: We presented two-tone
face stimuli at random locations equidistant from a central fixation point
while an annulus of CFS Mondrians flashed at the same eccentricity in the other
eye. Results: For each individual observer, we found a unique pattern of
breakthrough probability. Though these patterns were dissimilar between
observers, patterns remained stable over long time periods (< 1 week) within
observers. We found that these idiosyncratic patterns of breakthrough
probability were consistent for various levels of stimulus intensity (contrast)
and types of stimuli. We review possible mechanisms which could account for
such persistent spatial inhomogeneities in the incorporation of suppressed
stimuli into conscious percepts and suggest an attentional explanation for the
effect.
50. The
Ebbinghaus illusion requires consciousness of the inducers.
Peter Kohler1,
Maryam Zafer1, Eric A. Reavis1, and Peter U. Tse1.
1
To
what degree does information that is processed in the absence of consciousness
influence the contents of consciousness? In the classic Ebbinghaus illusion, a
target circle will be perceived as smaller than its veridical size when it is
surrounded by larger “inducer” circles, and larger than veridical when it is
surrounded by smaller circles. The illusion is a striking example of the effect
of context on visual phenomenology. Here we demonstrate that this effect is
dependent upon conscious awareness of the inducing stimuli. We applied a
modified version of continuous flash suppression (CSF) to the Ebbinghaus
illusion. In CFS, dynamic, high-contrast Mondrian patterns are flashed
sequentially to one eye while a static image is presented to the other eye,
which can render the static image perceptually invisible for long periods of
time (Tsuchiya and Koch, 2005). We presented naïve subjects with a display
containing two Ebbinghaus targets, one on each side of fixation, each
surrounded by inducers of a different size. In condition 1, the target circles
were presented to one eye, on a background of dynamic high-contrast Mondrian
patterns, while the inducing circles were presented to the other eye on a black
background. This had the effect of suppressing the inducers from conscious
awareness while the targets remained consciously visible. In condition 2, the
targets were presented on a black background, so that targets and inducers were
both consciously visible. In condition 3, targets and inducers were both
presented to each eye, on the flashing Mondrian background, so that both were
conscious. Subjects performed a two-alternative forced choice task indicating
whether the left or right target looked larger. We found that suppressing the inducers from
consciousness eliminated the Ebbinghaus illusion; i.e., in condition 1, targets
did not appear to differ in size as a function of the size of the unconsciously
presented inducers. In conditions 2 and 3, however, where inducing stimuli were
consciously visible, the Ebbinghaus illusion was strong. These results
demonstrate that the Ebbinghaus illusion is dependent upon conscious awareness
of the inducing stimuli.
51. The Contribution of Luminance, Contrast and
Ocular Dominance to Conscious Perception in Onset Rivalry.
Jody Stanley1, Olivia Carter1, and Jason Forte1.
1 Department of Psychological Sciences, The University of Melbourne j.stanley2@pgrad.unimelb.edu.au
When
an observer is presented with dissimilar images to the right and left eye,
conscious awareness of each image will alternate every few seconds in a
phenomenon known as binocular rivalry. In sustained viewing, the timing of
these switches appears to be unpredictable, but recent research has suggested
that the first conscious experience, or the ‘onset’ period of rivalry, is not
random and may be different in its neural mechanism. Differences in luminance
and contrast have a significant influence on average dominance during sustained
rivalry, and perception of luminance can vary between individuals and across
the visual field. We therefore investigated whether contrast also plays a role
in onset rivalry. Observers viewed equiluminant rival targets for brief
presentations in eight locations of the near periphery and reported the colour
that was first perceived in each location. Results show that minimizing
differences between luminance and contrast yields a stronger pattern of onset
dominance bias and reveals evidence of monocular dominance. These findings are hard to reconcile with current models of sustained
rivalry and suggest that different mechanisms may be responsible for
determining the initial period of perceptual dominance.
52. Conscious
access to subliminal stimuli via sensory deprivation.
Rémi Radel1
and Ap Dijksterhuis2.
1
University of
2
Background: Consciousness has a limited processing
capacity, which is mostly absorbed by environmental demands. As a need for
stimulation has been shown, reduction of external stimulation might lead
individuals to process smaller inner stimuli to fulfill this need. Therefore,
we investigated whether subliminal stimuli may enter into consciousness in case
of sensory deprivation. Method: This
hypothesis was tested with 72 participants who were randomly assigned in one of
three groups depending on the level of environmental stimulation. A first group
performed the experiment in a completely dark and silent environment. A second
group of participants was in a reduced stimulation environment, where random
noise could be heard in darkness. A last group was in a sensory stimulation
environment with regular lighting and random noise. All participants were
exposed to pre- and post-masked words displayed for 16ms. Then, participants
had to identify the masked word in a list of two words, similar in length and spelling.
Participants provided their answers either immediately after the presentation
of the word or after a 15s delay.
Results: A forced-choice task performed on the kind of font that was
used confirmed that masked words were really imperceptible (d’=.02). No
differences in words visibility were found across the environmental conditions
(F<1). A GLM performed with identification rates of masked words as the
criterion revealed a marginal effect of the delay before answering (p=.051),
which interacted with the environmental stimulation conditions (p=.023). While
there was no effect when answers were immediate, participants who were in the
sensory deprivation conditions identified the words better when their answers
were delayed. Their identification rates were above the chance level in this
case (M = .57). Discussion: Subliminal
stimuli have been traditionally described to be too weak to reach consciousness
and to decrease in time. Our result contrasts this view as we show that
subliminal stimuli can still enter in consciousness after some time when this
delay is free of external stimulation. This may be explained by the need for
stimulation that may orient individuals toward smaller inputs in case of
sensory deprivation.
53. A
common brain network underlying the attentional blink and the psychological
refractory period.
Sebastien Marti1,
Mariano Sigman2, and Stanislas Dehaene1.
1 Cognitive
Neuroimaging Unit, CEA / NeuroSpin sebastien.marti@yahoo.fr
2 University
of
Doing two things at once is difficult. When people
are asked to perform two tasks (T1 and T2) in close succession, their response
time for T2 is typically slower, the so-called psychological refractory period
(PRP). The central interference model of the PRP proposes that only a central
decision stage is strictly serial while sensory and motor processing occur in
parallel. In the present experiment, we tested the hypothesis that depending on
the duration of task 1, the conscious perception of T2 should be either delayed
or T2 might be completely missed (the Attentional Blink effect, AB). We used
magnetoencephalography to record the brain activity during a dual-task in which
T1 was a sound and T2 a letter embedded in a series of distractors. We found
that T2 sensory processing was unaffected by task overlap, but late T2 central
components were delayed until T1 processing was completed and completely absent
when participants missed T2. In addition, when the response time to T1 was
slow, T1 central components were larger, T2 central components were further
delayed and the proportion of missed T2 increased. Our data support the
hypothesis that the central decision stage is strictly serial. In addition,
when tasks overlap in time, T2 central access is delayed (the PRP effect) and
can even fail if T1 processing is too long (the AB effect).
54. Error-related
brain activity under subliminal versus conscious conditions.
Lucie Charles1,
Filip Van Opstal1, and Stanislas Dehaene1.
1 INSERM-CEA
Cognitive Neuroimaging unit lucie.charles.ens@gmail.com
Cognitive
control and metacognitive processes have been the object of intense research in
neuroscience for many years. However the question of how conscious perception
influences this type of processes remains unsolved. Nieuwenhuis et al. (2001)
investigated the influence of error awareness on two event-related brain
potentials, the error-related negativity (ERN) and the error positivity (Pe)
which occur respectively 100 and 300 ms after an erroneous response. They
observed an ERN even when subjects were unaware of making errors, suggesting
that one could detect brain activity linked to cognitive control in a
non-conscious situation. However this study focused exclusively on error
awareness. By contrast, we investigated
how error-related brain activity is modulated by awareness of visual stimuli
presented below or above the threshold for conscious access. Our study
addressed this question by simultaneously using magneto- and
electroencephalography techniques. We used a continuous backward masking
paradigm identical to Del Cul et al. (2007), with a variable target-mask
stimulus-onset asynchrony (SOA). On each trial, subjects reported both their
visibility of the target, and their evaluation of their performance (correct or
incorrect). These subjective measures allowed us to study the modulation of the
ERN component in various conditions of visibility and metacognitive report. No
ERN was observed in the shorter SOA conditions (high-masking condition) whereas
it was present in the longer SOA conditions. Indeed, the ERN varied in parallel
to stimulus visibility showing a very similar threshold-like profile as a
function of SOA. These results suggest that the ERN is drastically reduced
under complete subliminal conditions, i.e. when subjects report not having seen
the stimulus. This is consistent with the hypothesis that subliminal visual
stimuli, compared to consciously accessed stimuli, fail to reach higher-order
cognitive control stages. Although these results seem at odds with Nieuwenhuis
et al. (2001) conclusion, we suggest that several factors differ importantly
between our two experiments that could explain these dissimilarities: (a) the
study of visual versus action awareness; (b) the fact that, in their experiment
error unawareness was not under experimenter control and might relate to a
different mode of conscious access disruption such as inattention.
55. Can
syntax be processed subliminally?
Anna-Marie
Armstrong1 and Zoltan Dienes1.
1 University
of
While it is well established that the semantic
properties of individual words can be processed subliminally, very little work
has addressed whether one can use syntax to determine the overall meaning of a
set of words. On the one hand, syntax operates almost entirely unconsciously in
normal language production and comprehension. On the other, the processing of
stimuli presented subliminally rather than consciously appears
impoverished. However, many studies
showing impoverished subliminal perception of meaning utilise objective
thresholds: these investigations are not just testing unconscious cognition,
but potentially degraded unconscious cognition (e.g. Lau & Passingham,
2006). Cheesman & Merikle (1984) first demonstrated that to determine the
full extent of unconscious processing, it is necessary to use a subjective
threshold. Two experiments were conducted to investigate whether subliminal
priming is sensitive to the meaning of word combinations and sentence structure
rather than just the meaning of individual words. The aim of experiment 1 was
to determine whether unconscious processing is capable of comprehending the
syntactic function of “not”, at an SOA just below the subjective threshold.
Having been primed with the instruction to e.g. “pick cat” or “not cat”,
participants were presented with the two words “cat” and “dog” and asked to
indicate which word they had been instructed by the prime to choose. Experiment
2 aims to determine whether people can process word order in active and passive
sentences, having been subliminally primed with one of e.g. “A attacks B”, “B
attacks A”, “A is attacked by B” or “B is attacked by A”, participants were
asked to judge which of two pictures best represents the meaning of the prime.
If the participant is able to correctly identify the appropriate picture, this
will provide evidence that the unconscious has understood both semantic meaning
and word order. Whether the results are null or positive, there will be
important implications for understanding the nature of unconscious processing.