Hemispheric differences for feature detection.

Abstract

The role of hemispheric processing for visual features was explored by tachistoscopically presenting subjects with stimulus displays composed of the letter I, displays in which a single T was embedded in an array of I's, or displays in which the letter O was embedded in an array of I's. The number of array elements was also manipulated (4, 16, or 36) to assess the effects of display size on featural detection for each visual field. Subjects verbally indicated whether array elements were all the same, or whether a T or O was present. Hemispheric error rates varied as a function of the type of letter to be detected, with left-hemisphere presentations producing superior performance for the detection of T's, right-hemisphere presentations yielding superior performance for the detection of O's, and Same displays demonstrating hemispheric patterns consistent with these results. The findings suggest that the analysis of perceptual features during visual stimulus processing may determine hemispheric outcomes in a variety of task situations.