Abstract

A number of lines of evidence reveal the operation of higher-level mechanisms in color vision. By higher-order mechanisms is meant elements beyond the second stage of most conventional models of color vision (or in physiological terms elements beyond at least the LGN). Analyses of the changes in the detectability of chromatic pulses induced by prior viewing for fields fluctuating in color reveal that such mechanisms play a role in determining visual sensitivity. While retinal processes involved in sensitivity regulation appear to be highly localized in their effects, the higher-level processes have a wider scope. For example, fluctuating conditioning stimuli have effects, not attributable to stray light, on stimuli presented to remote retinal regions. Precise measurements of simultaneous color contrast yield results which cannot be explained in terms of multiplicative or subtractive interactions in either receptoral or second-stage mechanisms and thus imply a role of higher-order mechanisms.

© 1987 Optical Society of America