Development of Attachment and Exploratory Behavior in Infant Squirrel Monkeys under Controlled Rearing Conditions

This study contributes to the understanding of early development of communication in squirrel monkeys (Saimiri). Emission of expressive behavior as well as its perception (as concluded from the partner's responses) form the basis of social communication. We studied stimulus conditions that control attachment and exploratory behavior two interdependent fields of motivation which are especially important in the early stages of development. Newborn squirrel monkeys were isolated from their mothers and the group and were provided with a mother surrogate, manipulanda, and social surrogate stimuli: objects were so designed as to elicit behavior which would otherwise be directed at conspecifics. It was found that the animals displayed largely normal attachment and exploratory behavior. They modified their behavior depending on whether their contacts with the social surrogate were answered by aversive or non-aversive calls in the same sense as socially experienced conspecifics would do. Consequently, the conclusion may be drawn that specific genetic components are involved in comprehending emotional expressions.