INTERHEMISPHERIC RELATIONS IN HIERARCHICAL PERCEPTION - A 2ND LOOK

This study reevaluates the role of interhemispheric interactions in th e consistency effect (global interference with local decisions) in hie rarchical perception. In an earlier study, Robertson et al. [22] (Nenr opsychology; Vol. 7, pp. 325-342, 1993) tested three split-brain patie nts on a hierarchical perception task in which stimuli, consisting of large (global) letters made up of smaller (local) letters; were unilat erally or bilaterally presented for identification. They found that, i n general, the consistency effect did not occur in split-brain patient s and argued that the effect is interhemispheric and normally mediated by the corpus callosum. We repeated the experiment with new stimuli i n two of the same split-brain patients. We found that both patients de monstrated evidence for global interference, implying that the neocort ical commissures are not necessary for eliciting the consistency effec t in hierarchical perception. Copyright (C) 1996 Elsevier Science Ltd.