| O'Regan, J.K., Noë, A. A sensorimotor account of vision and visual consciousness Behavioral and Brain Sciences 2001 (24)5 [html] |
| Many current neurophysiological, psychophysical and psychological approaches to vision rest on the idea that when we see, the brain produces an internal representation of the world. The activation of this internal representation is assumed to give rise to the experience of seeing. The problem with this kind of approach is that it leaves unexplained how the existence of such a detailed internal representation might produce visual consciousness. An alternative proposal is made here. We propose that seeing is a way of acting. It is a particular way of exploring the environment. Activity in internal representations does not generate the experience of seeing. The outside world serves as its own, external, representation. The experience of seeing occurs when the organism masters what we call the governing laws of sensorimotor contingency. The advantage of this approach is that it provides a natural and principled way of accounting for visual consciousness, and for the differences in the perceived quality of sensory experience in the different sensory modalities. Several lines of empirical evidence are brought forward in support of the theory, in particular: evidence from experiments in sensorimotor adaptation, visual "filling in", visual stability despite eye movements, change blindness, sensory substitution, and color perception. |
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| Churchland, P. Can Neurobiology teach us anything about consciousness ? Proceedings and Adresses of the American Philosophical Association 1994 [html] |
| Human nervous systems display an impressive roster of complex capacities, including the following: perceiving, learning and remembering, planning, deciding, performing actions, as well as the capacities to be awake, fall asleep, dream, pay attention, and be aware. Although neuroscience has advanced spectacularly in this century, we still do not understand in satisfying detail how any capacity in the list emerges from networks of neurons.[1] We do not completely understand how humans can be conscious, but neither do we understand how they can walk, run, climb trees or pole vault. Nor, when one stands back from it all, is awareness intrinsically more mysterious than motor control. Balanced against the disappointment that full understanding eludes us still, is cautious optimism, based chiefly on the nature of the progress behind us. For cognitive neuroscience has already passed well beyond what skeptical philosophers once considered possible, and continuing progress seems likely. |
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| Halligan, P., Oakley, D. Greatest myth of all New Scientist 2000 (168)2265:35-39 [pdf] |
| What do you mean when you talk about "yourself"? Leading neuroscientists Peter Halligan and David Oakley are rewriting the rules on consciousness. |
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| Block, N. On a confusion about a function of cousciousness Behavioral and Brain Sciences 1995 (18)2:227-287 [html] |
| Consciousness is a mongrel concept: there are a number of very different "consciousnesses." Phenomenal consciousness is experience; the phenomenally conscious aspect of a state is what it is like to be in that state. The mark of access-consciousness, by contrast, is availability for use in reasoning and rationally guiding speech and action. These concepts are often partly or totally conflated, with bad results. This target article uses as an example a form of reasoning about a function of "consciousness" based on the phenomenon of blindsight. Some information about stimuli in the blind field is represented in the brains of blindsight patients, as shown by their correct "guesses," but they cannot harness this information in the service of action, and this is said to show that a function of phenomenal consciousness is somehow to enable information represented in the brain to guide action. But stimuli in the blind field are BOTH access-unconscious and phenomenally unconscious. The fallacy is: an obvious function of the machinery of access-consciousness is illicitly transferred to phenomenal consciousness. |
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| Wegner, D.M. The mind's best trick: how we experience conscious will Trends in Cognitive Sciences 2003 (7)2:65-69 [pdf] |
| We often experience consciously willing our actions. This experience is so profound that it tempts us to believe that our actions are caused by consciousness. It could also be a trick, however the mind s way of estimating its own apparent authorship by drawing causal inferences about relationships between thoughts and actions. Cognitive, social, and neuropsychological studies of apparent mental causation suggest that experiences of conscious will frequently depart from actual causal processes and so may not reflect direct perceptions of conscious thought causing action. |
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| Zeki, S. Toward a theory of visual consciousness 1999 [pdf] |
| The visual brain consists of several parallel, functionally specialized processing systems, each having several stages (nodes) which terminate their tasks at different times; consequently, simultaneously presented attributes are perceived at the same time if processed at the same node and at different times if processed by different nodes. Clinical evidence shows that these processing systems can act fairly autonomously. Damage restricted to one system compromises specifically the perception of the attribute that that system is specialized for; damage to a given node of a processing system that leaves earlier nodes intact results in a degraded perceptual capacity for the relevant attribute, which is directly related to the physiological capacities of the cells left intact by the damage. By contrast, a system that is spared when all others are damaged can function more or less normally. Moreover, internally created visual percepts illusions, afterimages, imagery, and hallucinations activate specifically the nodes specialized for the attribute perceived. Finally, anatomical evidence shows that there is no final integrator station in the brain, one which receives input from all visual areas; instead, each node has multiple outputs and no node is recipient only. Taken together, the above evidence leads us to propose that each node of a processing-perceptual system creates its own microconsciousness. We propose that, if any binding occurs to give us our integrated image of the visual world, it must be a binding between microconsciousnesses generated at different nodes. Since any two microconsciousnesses generated at any two nodes can be bound together, perceptual integration is not hierarchical, but parallel and postconscious. By contrast, the neural machinery conferring properties on those cells whose activity has a conscious correlate is hierarchical, and we refer to it as generative binding, to distinguish it from the binding that might occur between the microconsciousnesses. |
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