Early rearing experiences and the performance of affinitive and approach behavior in infant and juvenile baboons

Abstract

We tested the hypothesis that subtle, short-term (birth to 3 months) differences in rearing experiences (peer-peer vs. mother-peer) produce measurable differences in the development and performance of four affinitive and four approach behaviors in late infancy (12 months of age) and in the late juvenile period (42 months of age). Data on 87 monkeys (45 males and 42 females) were obtained by a series of approximately 2,100 focal animal sampling sessions. Significant effects of rearing were found in two affinitive behaviors (Allogroom andHold) with mother-peer reared subjects having a higher mean rate of performance. There were no significant main effects or interactions among any of the approach behaviors. Several suggestions are proposed to account for the resistance of six behaviors (Muzzle-muzzle, Touch, Ear flatten, Follow, Lip smack andSocial approach) to the effects of the experimental procedures: (1) these behaviors may reflect genetically mediated behavioral characteristics of the species that are not modified by environmental conditions; (2) environmental conditions used in the study may have been too subtle and consequently insufficient to produce an effect on relatively resistant behaviors; or (3) effects of the early rearing experience on these behaviors may be observable only during adolescence or adulthood when the proper performance of these behaviors is more crucial to social success, social integration and reproduction.