[Delayed reactions of simians in a multiple-choice situation]

Delayed reactions were studied on six rhesus macaques and three chimpanzees by means of a modified multiple choice method. The data obtained showed that the initial capacity of short-term memory did not exceed the reproduction of two spatial discrete elements in macaques and of three elements of shimpanzees. It was found that successful operation with sets beyond the initial capacity of short-term memory did not exceed the reproduction of two spatial discrete elements in macaques and of three elements in shimpanzees. It was found that successful operation with sets beyond the initial capacity of short-term memory is due to secondary processes of formation of visual engrams and related motor stereotypes. The significance of extension of short-time memory capacity for the transition of higher animals from monodetermined reactions to active relations with their surroundings is discussed.