The significance of spatial factors on an initial segmentation and an active attentional phase was demonstrated by briefly exposing spatial configurations of elements, and then asking the subjects to reproduce the patterns or to search them for a target letter. The stimulus displays consisted of small o's forming different spatial configurations,…

Visual acuity as a function of target position and density was measured in a letter recognition task. A homogeneous pattern of equally-spaced elements was tachistoscopically exposed, where the target was never located at the boundaries of the pattern. The target was marked with a spatial cue to control attentional processes. With such a spatial…