Differences in performance of young and old monkeys on a visuospatial memory task

: Two groups of stumptailed macaques (Macaca arctoides) were compared in terms of performance on a visuospatial working memory task involving repeated presentations of an array of 15 doors, each of which concealed one food reward at the start of a session. Rewards obtained by the subject were not replaced. Errors were defined as responses to doors previously pushed open during the session. Both groups generally obtained all rewards and showed improved performance across sessions, but old monkeys consistently made more errors than young ones, especially in the latter half of a given session. Further, old monkeys were less diverse in the errors they made, indicating different response strategies by the two groups.