Abstract # 99:

Scheduled for Thursday, August 17, 2006 07:00 PM-09:00 PM: Session 8 (Regency West 1/3 ) Poster Presentation

Individual differences in temperament predict longitudinal stability of affiliative relationships in juvenile rhesus macaques (Macaca mulatta)

T. Weinstein1,2 and J. P. Capitanio1,2
1University of California, Davis, Department of Psychology, One Shields Ave, Davis, CA 95616, USA, 2California National Primate Research Center
     We previously demonstrated the importance of temperament in the formation of yearling peer affiliative relationships as assessed in the animals’ natal half-acre enclosures (Weinstein & Capitanio, 2005). Our current study follows up on these animals 6 months later to determine: 1) the stability of yearling peer preferences across development, and 2) whether individual differences in temperament predict variation in such stability. Using focal animal sampling, we recorded the affiliative interactions of 29 two-year-old rhesus macaques from two field corrals at the California National Primate Research Center over an 8-week period. We defined an affiliative preference using a Chi Square test to determine whether subjects spent more time with particular peers than would be expected by chance. Temperament ratings had been conducted during a colony-wide biobehavioral assessment when subjects were 3-4 months old. Subjects displayed stable peer preferences toward a mean of 1.5 animals (range: 0-3). Individuals high in Adaptability (i.e. demonstrated an easygoing and flexible response style during the infant assessment) displayed a larger number of stable preferences than animals low on this dimension (Spearman rho=0.41, p<0.05). These findings suggest that temperament ratings during infancy reflect a stable style of responsiveness that influences both the formation and maintenance of social relationships as juveniles integrate themselves into their troop’s social network.