Exploring personality structure and similarity in coppery titi monkeys (Plecturocebus cupreus).

Recent research has shown that personality similarity between pair-bonded individuals can lead to better compatibility and well-being in humans. In our study, we explored the personality of 27 pairs of captive coppery titi monkeys (Plecturocebus cupreus), using a Hominoid Personality Questionnaire of 54 personality items. We also examined the effect of pair duration, pair affiliation, and the presence of offspring on the personality of these pairs. We built a model with five components to describe titi monkey personality structure in our colony and labeled these components as aggressive, cool, cautious, innovative, and helpful. Helpful, which we relate to "agreeableness," was significantly higher in males than in females. Aggressive and helpful were correlated within couples. Helpful was also negatively related to the time spent since pairing. Innovative was higher for pairs with higher affiliation. Additionally, we compared personality similarity between a group of pairs that were created based on initial compatibility (determined via a "speed-dating" experiment), and a group of tenure-matched pairs that were determined quasirandomly. Pairs determined from speed dating were more helpful than pairs from the colony comparison group, which suggests that high levels of initial attraction may facilitate an increase in prosocial personality traits. Our findings, including the negative correlation of "helpful" with time since pairing and the heightened "innovative" trait in pairs with stronger affiliation, may suggest subtle dynamics within titi monkey personalities. These insights contribute to a broader understanding of nonhuman primate personalities. (PsycInfo Database Record (c) 2025 APA, all rights reserved).