Cognitive Preconditions for Responses to Fairness: An Object Retrieval Test of Inhibitory Control in Capuchin Monkeys (Cebus apella)

The authors explore the evolution of one cognitive mechanism required for altruistic behavior: the capacity to inhibit prepotent responses. Specifically, the authors used an object retrieval task to investigate whether capuchins (Cebus apella) can inhibit ii prepotent siraiegy of reaching directly for a food reward. Success in this task varies across species and across development, but is also known to depend critically on the maturity of dorsolateral prefrontal conex. ihe cortical area implicated in rejecting small payoffs in an Ultimatum Game. Capuchins easily inhibit the tendency LO reach directly for food in the object retrieval task, successfully employing an alternative reaching strategy even in the first session of performance. This contrasts with the performance of closely related tamarin monkeys, who pcrtormed less well despite extensive training. These results provide the lirst evidence that capuchins likely exhibit human-like inhibitory control in tasks previously linked to the function of the dorsolateral preirontal cortex, such as the Ultimatum Game.