Patterns of Social Attention in Mandrills, Mandrillus sphinx

Primates possess impressive cognitive abilities, especially in the social domain, and accumulate knowledge about their social environment. Studying how primates distribute their attention among group mates may help us understand how they obtain their social knowledge and what they consider as the most relevant social stimuli. We conducted 11 month of observations on glance rates in a captive group of 15 mandrills (Mandrillus sphinx). We investigated the factors affecting inter- and intraindividual variation in the attention paid to group mates. The total amount of attention given to group mates was related to the age, but not to the sex or the dominance rank of the subject. Mandrills looked more at high-ranking than at low-ranking group mates and more at their own kin than at nonkin. Furthermore, the attention directed to both the aggressor and its victim increased markedly after an aggressive episode. These results show mandrills actively monitor their group mates, thus presumably gaining valuable social information, and suggest that studying patterns of social attention may help to understand primate social knowledge and decision making.