Age Change in Learning Ability of Japanese Monkeys ( Macaca Fuscata ) Measured by the Transfer Index

Abstract

To examine the developmental change in learning 26 Japanese monkeys at five ages, 1, 2, 3, 5, and over 7 years old, were given two sorts of discrimination-reversal problems differing in prereversal acquisition, one at 67% and the other at 80%. Transfer Index was estimated. With a shift in acquisition from 67% to 80%, the Transfer Indexes were maintained in the 1-, 2-, and 3-yr. groups but declined in the 5-yr. and the adult groups. The results suggest some critical point in learning by Japanese monkeys.