Spatial thought, mental rotation and the right cerebral hemisphere

Abstract

Men with right, left and bilateral cerebral lesions were required to make right/left judgements under two experimental conditions, in one of which a mental re-orientation of the stimulus was presumed to be required. Schematic drawings of a man were exposed in either an upright or inverted position and, on each trial, one of the hands was marked. The subject's task was to say “right” or “left” depending on the hand marked. The right posterior group made fewer errors than the left posterior group under the upright condition but significantly more under the inverted condition. This result is attributed to their failure to perform an appropriate mental rotation of the inverted stimuli.