Hemispheric asymmetries in a tactile thought task for normal subjects.

14 normal subjects were given two tactile-recognition tasks. Subjects were asked to match the tactually presented nonsense figures to the visual-recognition display on a Non-rotation task. On the Mental-rotation task subjects matched the tactile figures which were presented in various directions by means of mental rotation to the visual display. A greater superiority of the left hand on the Mental-rotation task was noted while on the Non-rotation task no differences between hands were shown. The right hemisphere may contibute more strongly to higher thought processes especially those which do not need verbal mediation.