A new definition of Consciousness

Consciousness is a mystery. Where does it come from, what animals have it, when do we have it? What are we conscious of, and what not? These are the questions that bother philosophers and psychologists already for centuries. Recently, they are joined by brain-scientists, trying to find out what parts of the brain are responsible for generating conscious experiences. Research aimed at finding the Neural Correlate of Consciousness (the NCC) is booming. But where will that take us? A major problem with this approach is that consciousness is rather ill-defined. Until now, studying the NCC is based on 3rd person observations: Subjects (or animals) are asked (in one way or another) whether they do or do not have a conscious experience, and this is related to particular neural events, structures or pathways. In this way it is almost unavoidable to not also include in the NCC the neural machinery that enables speech, button presses, attention, and other processes required to translate a conscious experience in a report about that experience. In this way, consciousness is easily confounded with cognitive operations like attention, decision processing, working memory and the like. Some argue that these processes are an integral part of consciousness, while others strongly disagree. Hence the problem: who is going to decide what the NCC is when nobody agrees on the C? And given this struggle, what is finding the NCC going to contribute to our understanding of consciousness? My solution is to abandon the search for the NCC. This inverse approach should be replaced by a forward approach: Assuming that the brain has something to do with consciousness, we should take fundamental neural processes as a starting point. What general aspects of, for example, cortical processing can be established? Then the mental correlates of these neural processes are sought. From that I derive a neural definition of the conscious / unconscious dichotomy. This hypothetical construct can then be tested experimentally. In this proposal, I will focus on two different, yet central aspects of cortical processing, and seek their mental correlates. The first aspect is Depth of Processing (DoP), which is about whether stimulus is processed all the way along the sensori-motor hierarchy. The second is the Feedforward versus Recurrent Processing distinction. The hypothesis first states that DoP has no relation to consciousness. A deeply processed stimulus can just as well evoke a conscious experience as remain unconscious. Central to understanding the conscious / unconscious dichotomy is the Feedforward versus Recurrent Processing distinction. The tenet is that feedforward processing is always unconscious, while recurrent processing is always conscious. These predictions will be tested with fMRI, EEG and Transcranial Magnetic Stimulation (TMS) experiments in human subjects. If validated, this will support the underlying neural definitions. From this project will emerge a strictly neural definition of consciousness, that can be rigorously falsified or validated. We can (and as I will show, should) then abandon our traditional ideas about consciousness, based on introspection and 3rd person observations. That would allow us to objectively determine who is conscious, and of what, no matter what that person (or animal) is telling us, or can tell us about it. We will narrow the gap between brain and mind, not by bridging it, but by moving our notion of mind towards that of brain.