Social monkeys learn more slowly: Social network centrality and age are positively related to learning errors by capuchin monkeys (Cebus [Sapajus] apella).

The cognitive demand on animals to learn, maintain, and remember the complexities of social relationships is theoretically higher for individuals who live more complex social lives. Previous research has suggested that both across and within species, the cognitive ability to flexibly learn and manipulate information may increase with increased social complexity. In this study, we determined the relationship between social complexity and cognitive performance on 2 related tests of general learning: associative learning and reversal learning. Subjects were 16 members of a socially housed group of brown capuchin monkeys (Cebus [Sapajus] apella). A general learning score was extracted from a principal component analysis on learning rate across 5 repetitions of each of the 2 tasks. The complexity of each monkey's social life was characterised by their centrality in the grooming social network of the group. Generalised learning scores were predicted by age and network centrality, but in contrast to predictions, older monkeys and monkeys that were more central to the network made more errors. Future studies focusing on specific cognitive abilities that are theoretically linked to species-specific fitness and behavioural outcomes, rather than broad cognitive categories like learning, will be essential for clarifying the relationship between cognition and social complexity. (PsycInfo Database Record (c) 2020 APA, all rights reserved).