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Stan Franklin & Bernard BaarsTwo varieties of unconscious processing Stan Franklin and Bernard Baars In:- New Horizons in the Neuroscience of Consciousness – Eds. Elaine Perry, Daniel Collerton, Fiona LeBeau & Heather Ashton The authors distinguish between two forms of the unconscious, processing that is unconscious, but could become conscious, and processing that is never conscious. Material is argued to be capable of becoming conscious if it is relevant for determining what is the most important aspect of the environment for the subject to attend to. Conscious and unconscious brain processing appears to be very similar. The thinking here is based on Baar's global workspace theory for cognitive processing and consciousness dating from the late 1980s although extended in more recent years. The theory is rather abstract talking in terms of a distributed parallel systems and competition for attention between coalitions of neurons. However in terms of modern studies this can be related to spatially distributed neuronal assemblies oscillating in the gamma range that signal between different regions of the cortex, and appear to be necessary for consciousness. The basic feature of the global workspace system is the cognitive cycle of sensing, processing and action. The cycle starts with external sensory stimuli. A percept is assembled unconsciously and passed to the workspace, where it is matched up with relevant memories to produce a model of the subject's situation. Portions of this model are supposed to compete for attention in consciousness. Consciousness subsequently broadcasts mainly to procedural memory to select a suitable behaviour. Except for the compatibility of parallel processing with more recent gamma frequency theory, global workspace looks very characteristic of twentieth century consciousness theory. The description of what is supposed to happen is extremely abstract with hardly any reference to where in the brain any of this is taking place. The reference to a conscious broadcast is particularly opaque in this respect. The other characteristically twentieth century aspect of this theory is the complete absence of any reference to the emotional areas of the brain, the system apparently being driven by a purely cognitive cycle. Modern studies have indicated the importance of assessing the reward/punisher value of possible actions, and both subcortical and prefrontal responses to this assessment, which can guide behaviour and also react back on cognitive processing. All this appears to be left out in global workspace theory. |
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