Affective Responses to Inequity in Capuchin Monkeys

Danny Fernandez


Many studies have documented adverse affects to inequitable situations in non-human primates. The behaviors that have predominantly been examined include food taking, collecting, giving, and refusals between the primate subjects and the experimenters. However, no studies had looked at the affective responses to inequity in primates. In a recent study, four-year old children who were rewarded inequitably accepted the reward, however they showed affective signs of dissatisfaction. For this study, we looked for affective displays in capuchins during inequitable exchange tasks. We predicted that the capuchins that were experiencing inequity would show more signs of agitation and aggression than those in equitable situations. We saw no increase in agitation or aggression when subjects were treated inequitably. There was higher aggression towards partners who received the lower reward in inequitable situations and less agitation seen by partners during frustration controls. Future studies may find our hypothesized results using different methodologies.