Individual differences in adult foveal visual asymmetries

The existence and nature of asymmetries in the recognition of elements of a visually presented array have been topics of dispute. In the present study, 32 adults responded to a single vertical or horizontal bar embedded in one circle of a 5 times 7 array of circles by touching a plate corresponding to the orientation of the bar. Two thirds of the subjects were left superior, while one third were right superior. Performance was in general top superior and decreased with increasing distance from the center. Possible explanations for these asymmetries are examined in terms of sequential processing, acuity dominance, hemispheric specialization, and selective attention.