Attention and consciousness

Close to the physicalist end of the spectrum is the work of John Taylor, a mathematician and theoretical physicist at Kings' College London (www.mth.kcl.ac.uk/~jgtaylor/). The key to his model (CODAM: COrollary Discharge of Attention Movement) is based on the principle that without attention to an input there can be no awareness of it (Taylor, 2002). Consequently he investigates a specific brain mechanism called the 'corollary discharge' that is responsible for changes in attention. He expresses this within a framework of control engineering as shown in Fig. 5. The control model involves an object map within which objects are selected for 'coming into consciousness' by a competitive process involving working memory and the corollary discharge mechanism. Taylor distinguishes a 'pre-reflective self,' i.e., the feeling of ownership of the content of being conscious, with the corollary discharge, and equates it to 'pure consciousness experience'. He reasons that there exists a buffer in the model, the neural activity of which is the correlate of the consciousness of the organism. The corollary discharge signal appears in this buffer briefly, to be immediately followed by the sensory signal of that which has been attended as selected by the discharge. Therefore the pure conscious state is a temporal extension of the content-less pre-reflective self state.

The CODAM model allows Taylor and his colleagues to arrive at several important conclusions. For example, they explain the meditational processes aimed at achieving a state of 'pure consciousness' found in several Eastern religions. They argue that advanced forms of meditation force the attentional corollary discharge to block sensory input and turn to attending only to itself. Another application is the explanation of the at-tentional blink which occurs when someone is asked to attend to several objects presented in succession to one another. Schizophrenia, inattention blindness and blindsight are also approached through the CODAM model.

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