Objectives: Imitation is a highly conserved component of animal behavior with multifaceted connections to sociality across taxa. One intriguing consequence of imitation in primates is that it promotes positive social feedback from the imitated toward the imitator. This suggests that imitation in primates may facilitate positive social interactions, but few studies have tracked imitation in socially housed primates. Here, we designed a novel ethogram to characterize imitation between conspecifics, to better understand whether imitation is associated with affiliation between primates in a semi-natural setting. Materials and Methods: In this study, 15 juvenile rhesus macaques (Macaca mulatta) were observed at the California National Primate Research Center. Using focal sampling, frequencies of imitative events (e.g. following, postural mimicry, etc.) by the focal were observed over a course of 12 weeks. In separate observations, focal social behavior (e.g. aggression, play, etc.) was also observed. Results: Subjects that exhibited higher degrees of imitation were not necessarily more prosocial, but, consistent with our hypothesis, they received significantly more play overtures from social partners (p<.01). In addition, imitation rates generally decrease with age. Conclusions: Together, these results suggest that imitation is associated with receiving positive social behavior in a complex, semi-natural setting in primates, and that imitation may be more common in adolescence as opposed to adulthood. These preliminary results in a small sample set represent an important step in characterizing imitation in context of social interactions during development. Tracking these behaviors over time will elucidate whether imitation is directly recruiting these positive social interactions, as has been demonstrated in captivity.

Imitation Predicts Social Favor in Adolescent Rhesus Macaques (Macaca mulatta)