Effects of Social Environment on Play in Squirrel Monkeys: Resolving Harlequin's Dilemma

Yearling-male squirrel monkeys (Saimiri sciureus) were paired with play partners either matched or different from them in age and/or sex. The frequency of play was maintained at equally high levels with both matched and mismatched partners. However, play between mismatched partners was marked by an unusually high incidence of nondirectional wrestling, a less threatening form of playfighting, and an increase in role reversal, suggesting that youngsters had considerable flexibility in the use of alternate strategies to sustain play activity with partners who were atypical for them. These results also attest to the robustness of play and its importance in the behavioral repertoire. The technique of restricting youngsters to atypical play companions is suggested as an effective means of manipulating play, with minimal disruption of other social experiences, for long-term studies of the developmental impact of social play.