Retinal locus and acuity in visual information processing

Abstract

Much recent visual information processing research has employed linear or rectangular letter displays subtending up to 8 deg of visual angle in width. Subsequent theory based on these data has assumed the simultaneous availability to some central processor of all n targets. Data on retinal acuity suggest that this assumption is gratuitous. Six subjects served in a tachistoscopic speeded letter recognition task wherein display luminance, retinal target locus, number of alternative target positions, and stimulus degradation by superimposition of a dot grid were manipulated orthogonally. Identification reaction times increased on the order of 100 msec as targets were located 3 deg from the fovea center, and results under convergent operations in the design suggested that these reaction time increases were a manifestation of peripheral stimulus degradation factors (such as acuity, masking, and luminance) rather than more central cognitive processes. © 1977, The Psychonomic Society, Inc.. All rights reserved.