Development of a Cognitive Testing Apparatus for Socially Housed Mother-Peer-Reared Infant Rhesus Monkeys

摘要

Though cognitive testing of infant monkeys has been practiced for the past 40 years, these assessments have been limited primarily to nursery-reared infants due to the confounds of separating mother-reared infants for assessments. Here we describe a pilot study in which we developed a cognitive testing apparatus for socially housed, mother-peer-reared rhesus macaques under one year of age (Macaca mulatta) that allowed the infants to freely return to their mothers for contact comfort. Infants aged 151.2±18.3 days (mean±SEM; n=5) were trained and tested on an object detour reach task. Infants completed training in 5.0±0.2 days, and completed testing in 6.2±0.9 days. Across four days of testing, infants improved to nearly errorless performance (Friedman test: χ²=13.27, df=3, p=0.004) and learned to do the task more quickly (Friedman test: χ²=11.69, df=3, p=0.009). These are the first cognitive data in group-housed, mother-peer-reared rhesus monkeys under one year of age, and they underscore the utility of this apparatus for studying cognitive development in a normative population of infant monkeys.