Measurement of lateral differences for faces in a two-response paradigm

The experiments illustrated the effect of procedural factors in reaction time measurements on lateral differences between visual fields for faces in two-reaction paradigm. The subjects were instructed to decide whether two faces presented successively in the left or right visual field were the same or different. The two experiments differed in the situation of response buttons in horizontal line left-right (Experiment I), or in vertical line further-closer to the subject (Experiment II). Both experiments showed advantage of the right hemisphere, though in the Experiment I the differences between the left and right visual fields depended on the configuration of buttons applied. The results point to fact, that even slight procedural changes may effect the results.