Chronometric analysis of visual laterality differences

Abstract

Five experiments examined hemispheric differences in reaction time judgments to pairs of stimuli classified as "same" (either physically or nominally identical) or "different" in order to investigate the reliability of the findings of Cohen (1972) and Geffen, Bradshaw, and Nettleton (1972). Subjects responded bimanually to left visual field or right visual field presentations of stimulus pairs. "Same" matches to nominally identical stimuli gave consistently slower response times than "same" matches to physically identical stimuli. The predictions of Cohen (1972) and Geffen, Bradshaw, and Nettleton (1972), that reaction times would be faster for physically identical matches in the left visual field, and for nominally identical matches in the right visual field, were not verified. No indications of a "hemispheric asymmetry of function" were discovered. The effects of subject variability on experimental results, and the utility of reaction time measures as indicators of hemispheric asymmetry, were discussed.