Unilateral lesions of the frontal association area of either hemisphere in monkeys and chimpanzees resulted in no impairment of learned tasks. Bilateral lesions had no effect upon the performance of problem box and visual discrimination habits, but produced profound impairment of performance in delayed reaction situations. Incomplete bilateral lesions resulted in a shortening of the length of the possible period of delay. Extensive reeducation after operation failed to reestablish the habit in animals with complete lesions and did not materially improve the performance after partial lesions. This defect in memory cannot be interpreted as a generalized deterioration of intelligence, but appears to be a specific impairment of recent memory. The fact that no defect followed lesions of any but the frontal areas indicates a high degree of specialization in the associative functions of the cortex in primates in contrast to the widespread equipotentiality which has been shown to operate in the cortex of the lower animals.