Interhemispheric visual matching in the split brain

Three split-brained subjects, one (N.G.) with full forebrain commissurotomy and two (V.P. and J.W.) with callosotomy, made same-different judgments ab out pairs of visual stimuli that were flashed either unilaterally or bilate rally. In separate blocks of trials, the stimuli could differ in luminance, size, or color. In the bilateral condition, only J.W. scored above chance, and only minimally, on the luminance and size tasks. and none of the subje cts scored above chance on the color task. Accuracy was generally much high er, especially for V.P. and J.W., when the stimuli were unilateral. These r esults confirm that there is little or no interhemispheric transfer of the visual attributes of luminance, size or color in the split brain. (C) 2001 Elsevier Science Ltd. All rights reserved.