Peers as Primary Attachment Sources in Yearling Rhesus Monkeys (Macaca mulatta)

Peer bonds were examined in 2 experiments using juvenile rhesus monkeys to determine (a) whether specific attachment bonds are formed between age-mates, (b) whether preferred age-mates can provide a secure base, and (c) whether a previous attachment bond affects the quality of subsequent attachment bonds. In Experiment 1, 8 peer-only reared (PO) monkeys demonstrated a specific preference for a predicted favorite peer when given a choice between a familiar and 2 unfamiliar peers. In Experiment 2, PO Ss were placed in a novel setting with either their most preferred peer, a familiar but not preferred peer, or an unfamiliar peer, and their responses were compared with those of a 2nd group of monkeys, reared for their first 6 months of life by their mother. Both mother-reared (MP) and PO monkeys displayed significantly more intimate contact and significantly less distress when with their most preferred peer; nevertheless, even when they were with their most preferred peer, PO Ss exhibited more distress than MP Ss. Findings are discussed with reference to current attachment theory.