Cognition of Figural Transformation after Commissurotomy

Abstract

Cognition of figural transformation of the Structure-of-Intellect Model of Guilford was studied in five commissurotomy patienrs (Zaidel & Sperry, 1974; Bogen, 1975 ). The Form Perception Test used was a modification of the Cross-modal Spatial Relations Test of Levy (1969). She adapted this from the Space Relations subtest of the Differential Aptitude Test to investigate superiority of the right hemisphere in spatial relations ability. The present modification of Levy's test as well as the Differential Aptitude Test has already been shown to correlate well with Block Rotation, a marker test for cognition of figural transformation (Kurnar, 1975). T he Form Perception Test employed 10 wooden blocks and 10 multiple-choice response cards, each card containing 3 diagrams of which only one correctly represented one of the blocks. On the far side of an opaque screen, a block was placed in a patient's hand and left as long as he wanted to feel it. Then, in free vision the patient was asked to point to one of the three diagrams which, when cut and folded, will exactly make the block you felt. The subjects were three male (CC, LB, RY) and two female (NG, NW) patients between 20 and 48 yr. of age, who had undergone commissurotomy between 5 and 9 yr. prior to this investigation. The hands in which the tactile stimuli were presented were utilized in reverse order both days to counterbalance any initial laterality effect. The correct scores with the right hand of CC, LB, FLY, NG, NW were 6, 12, 6, 6, 2; the correct scores with the left hand were 12, 16, 11, 14, 12 respectively. The average performance of the left hands significantly exceeded that of the right hands (t = 3.42, p < .01), suggesting the functional superiority of the left hand and contralateral right cerebral hemisphere in this task involving cognition of figural transformation.