Comparison of personality domains derived from personality ratings and behavioral observations in Japanese macaques (Macaca fuscata)

Abstract Primate personalities are a phenomenon of widespread interest. Researchers have attempted to measure primate personalities using two main methods: personality ratings and behavioral observations. However, a lack of consensus exists on whether the same personality domains can be measured using different methods. In our study, we aimed to explore the personality structure of 32 free-ranging Japanese macaques ( Macaca fuscata ) using personality ratings and behavioral observations. A principal component analysis of personality ratings assessed via questionnaires (the Hominoid Personality Questionnaire) revealed three components: Dominance PR , Anxiety PR , and Friendliness PR . Behavioral observations across a wide range of measures in daily situations also revealed two Behavioral Components we term Sociability BC and Grooming BC . The behavioral domains captured individual tendencies in sociability, particularly with respect to the extent of interaction with kin. Comparison of the domains identified by the two methods showed that no overlapping domains were found. Furthermore, subject attributes such as rank and age were associated with Dominance PR and Friendliness PR . This may be attributable to the lack of contextual information in the observational data. The concept of “personality coherence,” whereby behavior changes according to situational demands, may be important for understanding the association between personality ratings and behavioral observations.