Memory for "what", "where", and "when" information in rhesus monkeys (Macaca mulatta)

Abstract

The present study examined working memory for what, where, and when information in rhesus monkeys (Macaca mulatta) using a computerized task. In Experiment 1, monkeys completed three delayed matching-to-sample (DMTS) tasks: (1) identity DMTS, (2) spatial DMTS, and (3) temporal DMTS. In Experiment 2, the identity and spatial tasks were combined so that monkeys had to report both what and where information about an event. In Experiment 3, the identity, spatial, and temporal tasks were combined to examine what-where-when memory integration. The rhesus monkeys reported all three components of the events, and there was some evidence suggesting that these components were integrated in working memory.

Figure 1

The identity, spatial, and temporal DMTS tasks. The identity task assessed memory for what information (i.e., the monkey had to select the photo that had been shown). The spatial task assessed memory for where information (i.e., the monkey had to select the location where the photo had been shown). The temporal task assessed memory for when information (i.e., the monkey had to select the symbol that was associated with the length of delay).