HAND PREFERENCES IN MONKEY - EFFECT OF UNILATERAL CORTICAL REMOVALS

Three pairs of monkeys (with one predominantly right-handed and one left-handed animal in each pair) were given unilateral removals of occipital, infero-temporal or posterior-parietal cortex, always from the hemisphere opposite to the preferred hand. Animals were trained on two visual and two tactile discrimination tasks before and after surgery; and on one new visual and tactile task for the first time after surgery. In only one animal (occipital) was there evidence of a differential alteration of hand preference by sense-modality of testing (the 2 parietal monkeys reversed their preferences in both modalities); and little, if any, support was obtained for the suggestion that there may be some minor degree of differential lateral specialisation for visual and tactile discrimination performance in the cerebral hemispheres of the monkey. © 1969.