Consciousness:

Behavioural, neural and computational correlates

Axel Cleeremans

Université Libre de Bruxelles, Belgium

What is consciousness? The short answer is: Nobody knows. Consciousness has long been considered as inaccessible to the scientific approach, and remains a mystery — “a phenomenon that people don’t know how to think about — yet” (Dennett 1991, p21). Of course, in an intuitive sense, we all “know” what consciousness is, at least roughly: It is “experience” — each of us knows, from the inside, what it is like to undergo seeings, feelings, hopings, that is, each of us is conscious. But what would a science of consciousness look like? How should one go about developing a scientific approach to consciousness, that is, to understand its mechanisms and physical basis? Because consciousness is so basic to human (and much animal) life, it is now widely taken to be one of the most important outstanding scientific problems. This is reflected in the spectacular renewed interest that the study of consciousness currently enjoys, in fields ranging from neuroscience to psychology and philosophy. As a case in point, while 1950 only saw the publication of five articles dedicated to consciousness in the biomedical literature, many thousands are now published every year. Entering the keyword “consciousness” in the Google search engine returns a truly staggering 55.000.000 documents. Dozens of books, several journals, a number of new scholarly societies (foremost among which the Association for the Scientific Study of Consciousness), and annual conference series further document what one could call a paradigm shift: the “Consciousness Boom”, also reflected in the fact that Scientific American listed the topic among its recent “top ten unsolved problems”.

Understanding the mechanisms involved in the conscious states we enjoy when perceiving, feeling, thinking, or acting requires a highly interdisciplinary approach that involves different disciplines (from neuroscience to philosophy; from artificial intelligence to psychology), different methods (behavioural, computational, and brain imaging methods), and different populations (from animals to pathological cases). This course will attempt to provide an broad overview of the issues involved in the study of consciousness, from foundational problems to methodological issues.

Course Outline

Day 1 Being a philosopher: Foundational issues in the study of consciousness [download presentation]

This part of the course is introductory and will be focused on several philosophical, theoretical, and epistemological issues that need to be addressed to advance the understanding of the mechanisms that subtend consciousness, addressing questions such as the following:

· Is the hard problem really hard?

· Can consensus be reached on a definition of consciousness?

· Does conscious experience have a function?

· Which computational principles differentiate information processing with and without consciousness?

Daniel Dennett, Consciousness: How much is that in real money?

Thomas Metzinger, The problem of consciousness

David Chalmers, The Puzzle of Conscious Experience

Day 2 Being a scientist: How do I measure consciousness? [download presentation]

Exploring the mechanisms of consciousness poses a genuine methodological challenge: How can one measure consciousness, if it is but a subjective, private state that is a priori unobservable? Day 2 will be focused on exploring the most promising behavioural paradigms to contrast information processing with and without consciousness as well as the most promising imaging methods. We will address the following questions:

· What are the most promising behavioural methods to assess subjective states?

· How may subjective and objective data may be best combined?

· What are the most promising online methods (e.g., MEG, fMRI, EEG, TMS)?

· How may such methods be best combined?

· How can brain imaging data analysis be refined?

· What is a neural correlate of consciousness?

David Chalmers, How Can We Construct a Science of Consciousness?

David Chalmers, What is a Neural Correlate of Consciousness?

Frith, C., Perry, R., & Lumer, E. (1999). The neural correlates of conscious experience: An experimental framework. Trends in Cognitive Sciences, 3, 105-114.

Day 3 Being a zombie: Differences between cognition with and without consciousness [download presentation]

There is a lot we can do without consciousness. Yet, consciousness is also clearly necessary for some cognitive functions. Day 3’s main focus will be on paradigms through which to distinguish information processing with and without consciousness. We will explore subliminal priming, implicit learning, implicit memory, and related phenomena, again keeping methodological and theoretical issues in mind:

· What are the best empirical paradigms to study consciousness, as distinct from attention or memory?

· How may unconscious cognition may be demonstrated?

· What are the implications of dissociation findings?

· Can one reconcile psychoanalytic approaches with the empirical study of consciousness?

Destrebecqz, A. & Cleeremans, A. (2001). Can sequence learning be implicit? New evidence with the process dissociation procedure. Psychonomic Bulletin & Review, 8(2), pp. 343-350.

Cleeremans, A., Destrebecqz, A., & Boyer, M. (1998). Implicit learning: News from the front. Trends in Cognitive Sciences, 2, 406-416.

Gaillard, V., Vandenberghe, M., Destrebecqz, A., & Cleeremans, A. (2006). First- and third-person approaches in implicit learning research Consciousness and Cognition, 15, 709-722.

Day 4 Being conscious: The function of consciousness and theories thereof [download presentation]

There is now a cornucopia of theories of consciousness, many of which make very different assumptions concerning the mechanisms involved in the emergence of conscious states and about how one should think of conscious experience. Some theories hold that that conscious experience is nothing more than a pure epiphenomenon and have no function per se. Others claim that consciousness has specific functions that have been shaped by evolution. One way to address such issues consists of developing computational models that one can then compare the “behaviour” of with actual empirical data, thus engaging in what one could call a “search for the computational correlates of consciousness”. This part of the course will thus provide an overview of the main theories and models of consciousness. We will review their main assumptions, attempting to develop a taxonomy of such models so as to isolate their main features.

· Is machine consciousness possible?

· What are the assumptions of global workspace theory?

· What is higher-order thought theory?

Atkinson, A., Thomas, M., & Cleeremans, A. (2000). Consciousness: Mapping the theoretical landscape, Trends in Cognitive Sciences, 4(10), 372-382. 308K .pdf

Crick, F. & Koch, C. (2003). A framework for consciousness, Nature Neuroscience Reviews, 6(2), p. 119-126.

Consciousness: Converging insights from connectionist modeling and neuroscience.Trends in Cognitive Sciences, 9 (8), 397-404

Day 5 Being Virtual: Consciousness, self-consciousness, and the self [download presentation]

A research topic of growing interest is the relation between self-consciousness as the awareness of one's own cognitive acts and the ability to ascribe certain mental states, such as perceptions, judgments, thoughts, feelings to others, the latter of which could be referred to as “social consciousness”. Recent advances in cognitive neuroscience have started to tackle these issues, which are of great interest for the understanding of certain psychopathological states including hallucinations, ego-disturbances, and delusions, respectively. With respect to self-consciousness and social consciousness, integrating these different cognitive capacities of self- other-distinction and taking the perspective of others, consciousness can be considered to be constitutive for the experience of personal identity. Day 5 will be dedicated to exploring such issues from a variety of perspectives ranging from development to social neuroscience.

· What is the relation between consciousness, self-consciousness and social consciousness?

· What are the relations between consciousness and personal identity?

· What is the relation between the concept of conscious intention and the social notion of moral responsibility for action?

· Do we have “free will”?

Cleeremans, A. (in press). Consciousness: The radical plasticity thesis. Progress in Brain Science

Cleeremans, A. & Sarrazin, J.-C. (2007). Time, action, and consciousness. Human Movement Science, 26(2), 180-202.

Assessment

Students taking the course for credit will be required to write a brief paper that critically overviews one or more of the articles read for class, or to comment on other work (particularly their own work) that is related to the issues discussed in class.

Axel Cleeremans

Université Libre de Bruxelles, Belgium

http://srsc.ulb.ac.be/axcWWW/axc.html

Axel Cleeremans, Ph.D. (1991), is a Research Director with the National Fund for Scientific Research (Belgium) and a Professor at the Université Libre de Bruxelles where he coordinates an advanced degree in Cognitive Science. Trained in neural network modeling at Carnegie Mellon University under the supervision of J.L. McClelland, Cleeremans' main research interests are in understanding the differences between learning with and without consciousness, and, more generally, in the mechanisms that underpin consciousness itself. Cleeremans currently acts as president of the Belgian Association for Psychological Science, and is also a member of the executive committee of the Association for the Scientific Study of Consciousness as well as of the board of the European Society for Cognitive Pscyhology. From 2007 onwards, Cleeremans will coordinate a COST Action titled “Consciousness: A transdisciplinary, integrated approach”.