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Key points
- The Association for the Scientific Study of Consciousness recently held its 26th conference.
- Talks demonstrated how perception is processed at extremely fine-grained levels of neuronal specificity.
- Research on cephalopods suggests that consciousness evolved not only in our line of vertebrates.
I recently attended the 26th session of the Association for the Scientific Study of Consciousness (ASSC) conference at New York University and recount in this post some prevailing trends. First, the basics: This conference and the institutionalization of the field itself are about a quarter of a century old; the other major conference takes place every two years in Tucson, Arizona; and it used to be called Towards a Science of Consciousness and now is called The Science of Consciousness. The latter conference is more of a "let a thousand flowers bloom" setting, while the ASSC has always taken itself very seriously and tended toward neuroscientific evidence. To underline this epochal conference and the legitimacy that the study of consciousness has achieved, two lions of the field, David Chalmers and Christof Koch, settled their 25-year bet on how close to achieving insight into the neural correlates of consciousness the field has come.
It turns out we are still a long way from where we would like to be, but there are plenty of fecund ideas and approaches that were on display at the conference. One interesting methodological approach is the "adversarial collaboration," in which researchers with competing hypotheses agree to run an experiment that will empirically clarify whose theory best explains the results. Many researchers are involved in such a project, and it seems to be a boon for graduate students aiming to make a splash or collaborate with more established scientists.
Three theories have stood the test of time and spawned cottage industries for experimentation and expansion. One is the Global Workspace Theory (GWT), originally spelled out by neurobiologist Bernard Baars. The gist of this approach is that the function of consciousness is to serve as a global broadcast of information and sensations that are of import to all the unconscious parts of the mindbrain laboring away in the dark. Since 1988, evidence has accumulated about this metaphor and eminent scientists Jean-Pierre Changeux and Stanislas Dehaene expanded it into a Global Neuronal Workspace (GNW). Some critics think the theory is overly cognitive, but it certainly helps us understand why some of the things the brain does become conscious while the thousands of other things it does at the same time do not.
The second prevalent theory is Integrated Information Theory (IIT), originally proposed by Giulio Tononi, in which neuronal signals are interpreted as information and the measure of consciousness is the mathematical adumbration of integration across the neural assembly. They are now on version 3.0 and for my money, it is still an incomplete approach to the problem.
The third major theory to remain standing is the Higher-Order Theory (HOT) of consciousness, which states that it is the recursive process of connections between parts of the brain, in particular frontal and cortical parts, which make a given set of activations conscious. While I have publicly critiqued the work, it remains a darling in the field. Two of the important theorists behind this idea, David Rosenthal and Rocco Genarro, were in attendance at the conference and Robert Van Gulick in his paper attempted to bring together HOT and GNW theories. Joseph Ledoux’s presidential lecture emphasized HOT, but veered into more interesting territory that surveyed the four realms of existence: the biological, the neurobiological, the cognitive, and the conscious.
The most interesting work was presented in keynote lectures. One by MacArthur genius neuroscientist Doris Tsao recounted advances in visual neuroscience in which her lab was able to demonstrate in consistent detail the manner in which macaque infero-temporal cortex processes faces. This was tied into a theory about how the relation between feedforward and feedback interpretations is central to the way the brain processes sensory information.
The other enlightening talk was given by Nobel prize winner May-Britt Moser, who recounted the journey she has taken with her husband Edvard Moser studying grid cells in the entorhinal cortex of the hippocampus in rats. They have been able to demonstrate that there are cells that preferentially respond to head direction, speed, borders, and object vectors. The new technology which made the above studies possible is called Neuropixels, which allows for the registration of the activity of thousands of cells simultaneously. The implications of both Tsao's and the Mosers' research will be worked out for years to come. Essentially, they both demonstrate how we can investigate how conscious perceptions are processed at extremely fine-grained levels of neuronal specificity.
A great figure in the field, Thomas Nagel, who published the seminal paper "What is it like to be a bat?" in 1974, gave an interesting lecture on neutral monism. This view coheres with my own work on monism, though some were puzzled by Nagel’s suggestion that there is a more primal substance underneath mental and physical properties that will one day be found even though he has no suggestions for how this might be accomplished.
Finally, we were treated to a panel on other minds, from bees to plants and octopi. Peter Godfrey-Smith gave an enlivening lecture about his work with octopi in Australia in which he described the neural dynamics of subjectivity. He claims that we may be able to generate experiential profiles of the total way that a thing feels in a given moment. His research on cephalopods is truly revolutionary because it suggests that consciousness evolved not only in our line of vertebrates but also analogously in another evolutionary line that separated from the mammalian line millions of years ago. It is awe-inducing, or terribly murky, to consider what it might be like to be an octopus, but the evidence is quite strong that they are conscious beings.
And so the field moves forward after having a good look at itself in this higher-order recurrent signaling event at ASSC.
