Reproductive Memory Processes in Chimpanzees: Homologous Approaches to Research on Human Working Memory

Abstract

Describes a method of investigating a chimpanzee's working memory using a reproductive procedure. There are two conventional ways to assess human working memory. These test how long the S can retain memorized information, and how much information the S can store at one time. Both of these approaches have been applied to testing the linguistic and numerical competence of a chimpanzee. A female chimpanzee, Ai, could hold information about a sample stimulus, and reconstruct lexigrams even with a 32-sec retention interval, if the sample stimulus contained three fundamental elements (K. Fujita and T. Matsuzawa, 1999). Ai could also memorize a random set of five numbers (N. Kawai and T. Matsuzawa, 2000). A recent study revealed Ai could memorize even six numbers (Kawai and Matsuzawa, in press). Taken together, Ai could memorize at least five items at one time, and retain the memory for some period of time, whatever the stimulus type (number or figure). Ai's performance tells us that a chimpanzee has a memory capacity that is comparable to that of humans. This suggests that the cognitive gap between humans and chimpanzees may be smaller than has been thought. Further research on chimpanzee cognition promises to increase our understanding of the origins of human intelligence. (PsycINFO Database Record (c) 2019 APA, all rights reserved)