Dr. Vince DiLollo's Psychoquium Talk Abstract
January 1996
From the time a stimulus first enters the eye to the time a perception emerges into consciousness, the initial stimulus has been encoded at several levels through the visual system. Models of visual information processing have attempted to specify the temporal sequence of the encoding events, and to describe the underlying mechanisms. In traditional models (e.g., Selfridge's "pandemonium", Craik & Lockhart's "levels of processing"), the sequence of events was deemed to be unidirectional: processing is said to take place discretely at each level, and to be then transferred to the next level.
I consider -- and provide neuroanatomical and psychophysical evidence for -- the option that processing is accomplished through iterative exchanges amongst levels. On this option, an initial wave of stimulation ascends rapidly through the system, followed by descending signals between levels. The descending pathways form part of an iterative-loop system aimed at reducing noise and establishing the most plausible perceptual interpretation of the incoming stimulus.
Dr. Dawson is a professor in the Deprtment of Psychology at the University of Alberta.
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