title: Comprehension of abstract concepts in right and left hemispheres of complete commissurotomy subjects.
abstract: The left and right hemispheres of three complete commissurotomy subjects were tested for the ability to comprehend abstract concepts. A technique was used which allows prolonged viewing of stimulus material restricted to a single visual hemi-field. Twenty-three trials involving a sample inspection figure and a three-choice answer array were presented to each hemi-field with instructions to point to the one picture in the choice array related to the sample. As none of the possible choices matched the sample stimulus on any concrete level, correct responses required an abstract mental association. Both the verbal and non-verbal hemispheres performed the task at a high level of proficiency in all subjects. It was further noted that both commissurotomy and normal subjects experienced difficulty in articulating the involved abstract relationship when asked to do so under a free vision condition. The results demonstrate that the right hemisphere, lacking a highly developed language system, can nevertheless support sophisticated cognitive processing at an abstract level, and further suggest that the associative process is not necessarily language-mediated in either hemisphere.
mesh_terms: D001244:Association; D002540:Cerebral Cortex / Q000502:physiology*; D003210:Concept Formation / Q000502:physiology*; D003337:Corpus Callosum / Q000502:physiology / Q000601:surgery; D004292:Dominance, Cerebral / Q000502:physiology*; D004827:Epilepsy / Q000601:surgery; D006801:Humans; D007802:Language; D014794:Visual Fields; D014796:Visual Perception / Q000502:physiology