Low-status monkeys "play dumb" when learning in mixed social groups

Many primates, including humans, live in complex hierarchical societies whe re social context and status affect daily life. Nevertheless, primate learn ing studies typically test single animals in limited laboratory settings wh ere the important effects of social interactions and relationships cannot b e study impact of sociality on associative learning, we compared the indivi dual performances of group-tested rhesus monkeys (Macaca mulatta) across Va rious social contexts, We used a traditional discrimination paradigm that m easures an animal's ability to form associations between cues and the obtai ning of food in choice situations; but we adapted the task for group testin g, After training a 55-member colony to separate on command into two subgro ups, composed of either high- or low-status families, we exposed animals to two color discrimination problems, one with all monkeys present (combined condition), the other in their "dominant" and "subordinate" cohorts (split condition). Next, we manipulated learning history by testing animals on the same problems, but with the social contexts reversed. Monkeys from dominan t families excelled in all conditions, but subordinates performed well in t he split condition only, regardless of learning history. Subordinate animal s had learned the associations, but expressed their knowledge only when seg regated from higher-ranking animals. Because aggressive behavior was rare, performance deficits probably reflected voluntary inhibition. This experime ntal evidence of rank-related, social modulation of performance calls for g reater consideration of social factors when assessing learning and may also have relevance for the evaluation of human scholastic achievement.