Evidence for different types of lexical representations in the cerebral hemispheres

Abstract

Forty right-handed, neurologically intact adults performed a lexical decision task with stimuli presented to the left visual field (right hemisphere) or to the right visual field (left hemisphere). Nonwords, low-frequency words, and high-frequency words were used as stimuli. Although an overall lefthemisphere advantage was observed for words, lateral differences did not differ according to word frequency. The results revealed further that when morphologically decomposable nonwords consisting of inappropriately combined legal stem plus suffix were presented in the right visual field they engendered more errors than matched nonwords that could not be parsed into stem plus suffix. In contrast, morphologically decomposable and nondecomposable nonwords engendered identical performance when stimuli were presented in the left visual field. These results were interpreted as suggesting that morphologically decomposed forms are only represented in the left hemisphere.