Not in need of reputation: Capuchin monkeys did not share more food when in the presence of an observer

Testing the two sides of indirect reciprocity in tufted capuchin monkeys. Gabriele Schino et al. Behavioural Processes, November 28 2020, 104290. https://doi.org/10.1016/j.beproc.2020.104290

Highlights

• We studied two aspects of indirect reciprocity in tufted capuchin monkeys.

• Recent groomers did not receive increased grooming, compared to recent groomees.

• Capuchin monkeys did not share more food when in the presence of an observer.

• We conclude that capuchin monkeys do not engage in indirect reciprocity.

Abstract: We addressed two different aspects of indirect reciprocity in tufted capuchin monkeys (Sapajus spp.) studying two common cooperative behaviours, grooming and food sharing. In an observational study, we tested whether capuchin monkeys were more likely to groom an individual that had just groomed a group mate than an individual that had not groomed anybody. In an experimental study, we tested whether capuchin monkeys were more likely to share their food with a partner when in the presence of a bystander (or of an image of the eyes of a conspecific) than when alone with their partner. In the observational study, we found an increase in the likelihood of receiving grooming after giving grooming, but this effect seemed to depend on social facilitation rather than on indirect reciprocity, as we found a similar effect after receiving (rather than giving) grooming. In the experimental study, the presence of a bystander or of an image of eyes did not affect the amount of food transferred to a group mate. Overall, these results suggest capuchin monkeys do not engage in indirect reciprocity.

Keywords: Indirect reciprocitysocial facilitationgroomingfood sharingSapajus spp.