Social context affects how rhesus monkeys explore their environment.

Abstract

This study reports on social modulation of exploratory behavior and response to novelty by members of a captive rhesus monkey colony. The group was trained to split in half, with one subgroup composed of dominant members only, the other of subordinates. The animals were then presented the same initially novel stimuli (i.e., sand-filled metal boxes containing hidden food items) in two social contexts differing in hierarchical composition. In a combined context, all group members (i.e., both subgroups together) were simultaneously presented the stimuli. In a split context, only members of the top or bottom half of the group (i.e., each subgroup in turn) was independently presented the stimuli. Subordinates responded similarly to dominant animals in the combined context but differently in the split context, where they were far more hesitant. Rank-related differences were evident in the way animals used their home compound and in their approach and responsiveness toward the stimuli. These findings show that social context influences how animals explore novel situations, possibly reflecting different social roles or status effects on the perception of social structure. Also, despite the complexity of primate social relationships, the separation technique produced no permanent or adverse effects on the social integrity of the group. This study shows that manipulating the social environment through separation training can be a powerful tool for assessing contextual influences on behavior.