Spatial characteristics of selective attention in letter matching

Abstract

Circular arrangements of eight letters around a central fixation point were tachisto-scopically presented. Two bar indicators appeared either simultaneously with or 80 msec before the letters, designating a pair of letters at any of four spatial separations for a same/different judgment. The subject indicated with a lever movement whether the members of the pairs were same or different. The principal concern was the effect of physical separation between target letters when all letters appeared on foveal locations of equal acuity. Reaction time (RT) varied nonmonotonically with spatial separation, with adjacent and diametrically opposite pairs being fastest. Leading indicators produced faster responses than simultaneous indicators. “Same” judgments were faster than “different” judgments. Effects of interhemispheric or intrahemispheric presentation and orientation were such that they could not account for the spacing effect, nor could peripheral effects such as masking. © 1976, The psychonomic Society, Inc.. All rights reserved.