Abstract
Formation of learning set and long-term memory in position recognition tasks of aged and young Japanese monkeys (Macaca fuscata) were studied. Four aged and three young monkeys were trained in an original position recognition task. Although all the monkeys learned this simple task, the aged monkeys needed more trials than the young ones. In six transfer tasks that followed, they experienced essentially the same position recognition task, but contextual cues, such as objects and the stimulus tray used, were changed across each transfer task. In the beginning of the transfer tasks, the young monkeys transferred their performance completely. In contrast, the performance of the aged monkeys declined because of the change. The ability to retain information in the aged monkeys was intact. Both the young and aged monkeys did not show any performance deficit even after a four-month retention interval, when the contextual cues were unchanged. These results suggest that learning in the aged monkeys was heavily dependent on the contextual cues, even if these cues were irrelevant in a task.
