TARGET DETECTION IN ONE VISUAL-FIELD IN THE PRESENCE OR ABSENCE OF STIMULI IN THE CONTRALATERAL FIELD BY RIGHT-HANDED AND LEFT-HANDED SUBJECTS

Marked differences in detectability are observed as a function of retinal locus when subjects are required to find a briefly exposed target pattern of uncertain location in the presence of a number of discriminably different nontarget patterns. Our previous studies using this search paradigm have attributed these detectability differences, and the right visual field detectability superiority associated with them, to a serial (scanning) mechanism which tends to examine stimuli in the right field earlier than those in the left. The present experiment, performed on large groups of right- and left-handed subjects, was designed to test the hypothesis that there are two independent serial processors, one in each hemisphere-an hypothesis which might account for the differences in detectability within and between the two half-fields in terms of hemispheric processing differences. The results are inconsistent with the dual independent serial processor hypothesis but are fully consistent with a single serial processor, a scanning mechanism, which has access to the information presented to both visual half-fields. © 1990.