Right-hemisphere language processing in normal right-handers.

Three experiments were conducted to investigate the verbal performance of the right cerebral hemisphere in right-handed individuals with normal intact brains. A manual reaction time (RT) measure was used to assess the relative efficiency of lateral stimulus-response pathways (e.g., left visual field-right hemisphere-left hand) in processing linguistic information. Experiment 1 showed that the right and left hemispheres were equally efficient at recognizing concrete object nouns in a lexical decision task. The RT data also suggested that abstract nouns may be recognized only by the left hemisphere. Experiments 2 and 3 demonstrated the right hemisphere's ability to detect semantic relationships between concrete nouns and their superordinate categories. The findings were discussed in terms of their consistency with data from split-brain research and their implications for models of the functional organization of language skills in the normal brain. It was proposed that the right hemisphere in the intact brain can play a functional role in processing language.