Plenary speakers

ASSC6 will offer an outstanding plenary programme through which different perspectives on language and consciousness will be developed. The plenary speakers listed below will each address this issue based on philosophical, neuropsychological, computational, and psychological approaches:

[ABSTRACT ASSC6-PL-03]

Rationality and Reasoning Without Language

José Luis Bermúdez

Contact:
José Luis Bermúdez (jb10@stir.ac.uk)
Department of Philosophy
University of Stirling
Stirling FK9 4LA

Explaining the behavior of non-linguistic creatures in psychological terms requires attributing to them beliefs and desires that in some sense rationalize their actions. Clearly, therefore, we need a notion of rationality that is applicable at the non-linguistic level. The paper suggests that the standard inference-based conception of rationality is inapplicable to non-linguistic creatures. There is no evidence of mastery of logical concepts in the absence of language. The paper describes three different senses in which the behaviour of non-linguistic creatures can be described as rational and explores the consequences for our understanding of non-linguistic creatures.

 

[ABSTRACT ASSC6-PL-15]

A Fork in the Road to the Neural Correlate of Consciousness

Ned Block

Contact:
Ned Block (ned.block@nyu.edu)
Department of Philosophy
New York University
Main Bldg, Room 502ª
100 Washington Square East
New York NY 10003

An impressive body of evidence suggests that the neural correlate of visual consciousness is to be found in higher areas in the occipeto-temporal stream of processing, different areas for different kinds of stimuli. But there are circumstances in which these areas are activated, seemingly without consciousness, apparently due to failure of normal processing in parietal areas. One possibility is that visual consciousness has a complex neural correlate involving events in both the occipeto-temporal stream and parietal and maybe frontal areas. Another possibility is that the neural correlate of visual consciousness is entirely confined to the occipeto-temporal stream but that attentional factors centered in the parietal areas are required for the visually conscious states to be accessible and that this access brings in the frontal areas. These two options represent very different strategies in research on what consciousness is in the brain. The paper discusses the pros and cons of both strategies.

 

[ABSTRACT ASSC6-PL-14]

Synesthesia, Qualia and Consciousness

Edward M. Hubbard

Contact:
Edward M. Hubbard (edhubbard@psy.ucsd.edu)
Department of Psychology
University of California, San Diego
9500 Gilman Dr. 0109
La Jolla, CA 92093-0109 USA

Peopple with grapheme-color synesthesia report the novel conscious experience of seeing specific colors when viewing specific letters and numbers. We have previously shown that these synesthetic colors can lead to the pop-out and texture segregation (Ramachandran & Hubbard, 2001). Additionally, we have demonstrated a form of "blindsight" in synesthesia. When subjects are asked to identify stimuli in the periphery, they are significantly better when the stimulus is presented alone, as opposed to when it is flanked with distractors ("crowding"). When presented with crowded graphemes, our synesthetes cannot perceive the grapheme, but do experience colors, saying, "I can't see the middle number but it must be an H because it looks green." Based on this memory association, synestehtes perform significantly better than control subejcts in identifying the target grapheme. We now report that synesthetically induced colors are not experienced when stimuli are presented at isoluminance, or at low luminance contrast, even though the inducing grap

[ABSTRACT ASSC6-PL-06]

The end of anonymous phenomenology?

Anthony I. Jack

Contact:
Anthony I. Jack (ajack@light.wustl.edu)
Washington University Campus Box 8225
4525 Scott Avenue
St Louis, Missouri 63110
USA

What is the scientific status of subject reports? Current attitudes in cognitive science are complex, yet the mainstream consensus is clear: Reports can provide interesting, even important, anecdotal evidence. Yet, real experimental 'results' must be established by objective evidence.

In this talk I will discuss some basic philosophical issues and relate them directly to scientific practice. Different views on the methodology for a 'science of consciousness' relate to different philosophical positions on the meaning of mental state terms. My position offers an alternative to Dennett's neo-behaviorism and to the neo-Cartesian views of Searle, Chalmers and Block. Cognitive science can, and should, transform itself into the science of consciousness. It can do so simply by changing its attitude to introspective evidence.

 

[ABSTRACT ASSC6-PL-12]

Conscious and Unconscious Aspects of Language Structure

Ray Jackendoff

Contact:
Ray Jackendoff (jackendoff@brandeis.edu)
Dept of Psychology
Brandeis University
Waltham, MA 02454
USA

The structure of language includes three major components: Phonological
(sound) structure, syntactic (phrase) structure, and conceptual (meaning) structure. Of these components, the one that appears to correspond most closely to the phenomenology of language is phonological structure: we hear strings of words, both in hearing others speak and in our own linguistic imagery. I will conclude that, with the exception of certain very coarse features, the structure of thought/conceptualization is entirely unconscious. I will showe how this relation between language and consciousness accounts for a number of puzzles in philosophy of mind and philosophy of language.

 

[ABSTRACT ASSC6-PL-04]

The early development of executive function: A levels of consciousness approach

Philip David Zelazo

Contact:
Philip David Zelazo (Zelazo@psych.utoronto.ca)
Department of Psychology
University of Toronto 100
St. George Street
Toronto, ON M5S 3G3
CANADA

In this talk, I will discuss the Levels of Consciousness (LOC) Model, according to which age-related in the conscious control of behavior depend on age-related increases in self-reflection that permit children to formulate and use increasingly complex systems of action-oriented verbal rules.

 

[ABSTRACT ASSC6-PL-09]

Consciousness, Attention, and Reportability

Jesse Prinz

Contact:
Jesse Prinz (jesse@subcortex.com)
SAS Philosophy Programme
University of London
Senate House, Malet Street
London, WC1E 7HU, ENGLAND

Many of our conscious states seem to be reportable. This raises two important questions. Why is there a link between consciousness and reportability? And, Is that link necessary? I defend a neurofunctional theory of consciousness that helps provide answers. (A neurofunctioanl theory is one that explains consciousness by appeal to brain states, but characterizes those states in terms of their functional role, at both local and psychological levels of analysis.) According to the theory, consciousness arises when hierarchically organized sensory systems send afferent signals to working memory systems via dynamic changes in connectivity modulated by selective and ambient attention. Because working memory plays a central role in reportability, conscious states are typically reportable. They are not necessarily reportable, however. I present a principle that distinguishes conditions under which conscious states will be reportable, and I offer an argument for denying the existence of unreportable conscious states that meet those conditions. I also use this analysis to raise two implications for the alleged distinction between access and phenomenal consciousness. First, all phenomenology requires access on the theory I defend. Second, the construct of access can be subdivided into two distinct notions, corresponding to availability to working memory and encoding in working memory. I argue that only the former is essential to consciousness.


[ABSTRACT ASSC6-PL-02]

On the content of chimpanzee consciousness

Daniel J. Povinelli

Contact:
Daniel J. Povinelli (ceg@louisiana.edu)

Institute of Cognitive Science
University of Louisiana at Lafayette
Rougeou Hall Room 348
241 East Lewis Street Lafayette
Lafayette, LA 70504-3772
USA

In this talk, I describe a theory concerning differences in the nature of the concepts which may populate the minds of chimpanzees and humans. Although the minds of humans and chimpanzees may share many kinds of concepts in common, recent evidence suggests that chimpanzees may be quite limited in their ability to generate concepts of unobservable entities. In particular, I review the evidence concerning their understanding of mental states (e.g., intentions, beliefs, percetions, desires) and causal phenomena (e.g., gravity, force, weight, physical connection). I conclude that although concepts of these kinds develop early in human development, there is substaintial reason to think that chimpanzees do not form them at all. Instead, they appear to be specialized in reasoning about the observable manifestations of such unobservable states and phenomena.

 

[ABSTRACT ASSC6-PL-07]

Why Are Verbally Expressed Thoughts Conscious?

David M. Rosenthal

Contact:
David M. Rosenthal (drosenth@artsci.wustl.edu)

Clark-Way-Harrison Visiting Professor
Program in Philosophy, Neuroscience, and Psychology
Washington University in St. Louis
(January-June 2002)

Department of Philosophy
Campus Box 1073
One Brookings Drive
Washington University in St. Louis
St. Louis, MO 63130-4899

It's generally recognized that there a close tie between consciousness and speech. One reason is that it seems that all verbally expressed thoughts are conscious. But it's not easy to explain this connection. We can't appeal to speech acts' being deliberate actions that require conscious mental antecedents, since speech acts are seldom deliberate and deliberate action can result from nonconscious antecedents.

A natural explanation does, however, flow from the higher- order-thought (HOT) hypothesis, on which a mental state's being conscious consists in its being accompanied by a seemingly nonin- ferential thought that one is in that state. We recognize, simply by being linguistically competent, that the speech acts of saying that p and saying one thinks that p have the same performance
conditions, even though their truth conditions differ. So, when- ever one says that p, one could equally have said one thinks that p. The best explanation is that, whenever one says that p, one actually has the HOT one would express by saying one thinks that p. This also points to an explanation of why one's saying one thinks that p is an exception--why one isn't then conscious of the thought one's speech act expresses, but only the thought one thereby reports.

 

[ABSTRACT ASSC6-PL-08]

Re-representing consciousness: Dissociations between experience and meta-consciousness

Jonathan W. Schooler...

Contact:
Jonathan Schooler (schooler+@pitt.edu)
Department of Psychology
518 Learning Research and Development Center
3939 O'Hara St.
University of Pittsburg
Pittsburgh, PA 15260

A distinction is drawn between conscious experience and the explicit awareness (meta-consciousness) of that experience. Whereas experience is continuous, meta-consciousness is hypothesized to occur only intermittently in response to goal failures, self-reflection, or requests for self-reports. Two types of dissociations follow from the notion that meta-consciousness involves the intermittent re-representation of the contents of consciousness. Temporal
dissociations occur when an individual, who previously lacked meta-consciousness about the contents of consciousness, directs meta-consciousness towards those contents. The case of catching one's mind wandering during reading illustrates a temporal dissociation. Once meta-consciousness is triggered, translation dissociations may occur if the re-representation process misrepresents the original experience. Such translation dissociations are particularly likely when one verbally reflects on non-verbal experiences or attempts to takes stock of subtle/ambiguous experiences. This review describes empirical evidence for temporal and translation dissociations and explores their implications for conceptualizing consciousness.

 

[ABSTRACT ASSC6-PL-10]

Artificial Collective Consciousness

Luc Steels

Contact:
Luc Steels (steels@arti.vub.ac.be)
Vrije Universiteit Brussel Artificial Intelligence Laboratory
Pleinlaan 2
1050 Brussels

Sony Computer Science Laboratory - Paris

There has been much speculation on the ability and inability of a robot to be conscious. For some, a conscious robot is a contradiction in terms - even though it may be an interesting source of thought experiments.
Others argue that certain aspects of consciousness (such as attention or reflection) are necessary for a very complex autonomous agent engaged in sensori-motor processing, planning or language and that therefore these aspects will progressively appear in robots as they become more complex. In this talk I want to address the issue of collective consciousness. How can there be a sense of conceptual coherence in a population of distributed individuals which, at least at first sight, do not have any direct physical access nor control to each other's internal brain states. Innate archetypes or quantum physics has been invoked to explain this kind of coherence. I will argue however that
this need not be the case and show in multi-agent simulations how iterated interactions between adaptive agents may cause the self-organisation of shared concepts and interpretations of reality.

 

ABSTRACT ASSC6-PL-01  

Aware or unaware? Verbal and Non-Verbal Assessment of Blindsight

Petra Stoerig

Contact:

Petra Stoerig (petra.stoerig@uni-duesseldorf.de)
Institut für Experimentelle Psychologie II
Heinrich-Heine-Universität
Universitätsstr. 1
D-40225 Düsseldorf
GERMANY

In human and non-human primates, lesions of the primary visual cortex produce visual field defects. Again in both species, residual detection, localization, and discrimination of visual targets can be demonstrated with
forced-choice paradigms, but only the human patients can be asked whether or not they perceive any of the stimuli they respond to. To learn whether the disscociation between visual awareness and visually guided behaviour that characterizes Blindsight is found in both species, Alan Cowey and I combined a forced-choice localization with a signal detection task in an attempt to non-verbally assess visual awareness. Four hemianopic monkeys and four human subjects, two with absolute defects, one with a relative hemianopia, and one with absolute as well as relative regions of cortical blindnesss were tested. First, 2AFC manual localization of 200ms square-wave grating stimuli was measured as a function of contrast. In addition, the human subjects gave verbal 'seen'-responses which were consistently at 0% in the absolutely blind regions. The second task was similar to the first in that stimuli which could appear in either hemifield were to be localized as before. In addition, on a varying proportion of trials no stimulus appeared, and to indicate these blank trials, a 'no'-area now constantly present above the central startlight was to be touched. Results showed that the human subjects' indicated a blank whenever a localizable stimulus appeared in the absolute defect, but indicated a stimulus on a proportion of trials presented in the relative defects. The non-verbal responses thus matched the verbal ones quite well. As the monkeys only very rarely touched stimuli in their hemianopic field when being given the chance to indicate a blank instead, it seems that monkeys have no conscious vision in the hemianopic field but show blindsight like human patients.

 

ABSTRACT ASSC6-PL-11

Unconscious semantic priming

Pío Tudela

Contact:
Pío Tudela
Department of Psychology
University of Granada
Campus de Cartuja
18001 Granada
SPAIN

The existence of unconscious semantic processing has been a highly debated and theo-retically relevant issue both in the realm of attentional as well as perceptual research. In our lab, we have approached this problem using a semantic priming procedure in which awareness of the prime was varied in two different ways. First we employed a backward masking procedure to prevent conscious detection and identification of the prime as measured by both subjective and objective awareness thresholds Second, awareness of the prime was manipulated by changing the distribution of attention over the visual field and by studying the semantic priming produced by parafoveally pre-sented primes. Our results consistently show semantic priming produced by primes of which participants are unaware.

In the first part of my lecture I will present and discuss behavioral data supporting un-conscious semantic priming. In the second part, I will present data based on event related potentials (ERPs) suggesting that the scalp signature associated to the prim-ing effect produced by unconscious primes is different, both in time and topography, from the scalp signature associated to the priming effect produced by conscious primes. I will comment our results in the context of present cognitive neuroscience research.

 

[ABSTRACT ASSC6-PL-05]

A dualism of dependent variables

Larry Weiskrantz

Contact:
Larry Weiskrantz (larry.weiskrantz@psy.ox.ac.uk)

University of Oxford
Dept. of Experimental Psychology
South Parks Road
Oxford OX1 3UD
UK

Several examples - taken mainly from neuropsychology - will be given of the insufficiency of on-line measures for concluding that a person or animal is conscious of ongoing events (Astate consciousness@). Off-line confirmation as well as the on-line measure is necessary. In humans this is typically, but not necessarily, a report by the subject; in animals it usually has to be experimentally contrived. Experimental research on the status and the underlying mechanisms of state consciousness is dependent on the conjunction and/or disjunction of the systems underlying both dependent variables. Some fMRI and event-related potential evidence will be discussed in relation to a putative on-line posterior processing system and an anterior commentary system..


[ABSTRACT ASSC6-PL-04]

The early development of executive function: A levels of consciousness approach

Philip David Zelazo

Contact:
Philip David Zelazo (Zelazo@psych.utoronto.ca)
Department of Psychology
University of Toronto 100
St. George Street
Toronto, ON M5S 3G3
CANADA

In this talk, I will discuss the Levels of Consciousness (LOC) Model, according to which age-related in the conscious control of behavior depend on age-related increases in self-reflection that permit children to formulate and use increasingly complex systems of action-oriented verbal rules.