Abstract # 202:

Scheduled for Monday, September 19, 2011 08:45 AM-09:00 AM: Session 25 (Meeting Room 408) Oral Presentation


J. M. Sullivan1, H. D. Freeman2, N. Schultz-Darken1 and S. Brosnan2
1Wisconsin National Primate Research Center, 1220 Capitol Ct, Madison, Wisconsin 53715, USA, 2Georgia State University, Department of Psychology

Although some primates show negative responses to inequitable rewards, not all do. Cooperation may be critical in priming a response, as the two species which show a strong response are both highly cooperative (Cebus apella, Pan troglodytes) and two others which do not are not cooperative (Pongo pygmaeus, Saimiri spp.). Thus cooperative breeders are an intriguing case. Although one cooperatively breeding species (Saguinus oedipus) shows only a limited response to inequity, this species responds differently in prosocial food donation tasks than another cooperative breeder, the common marmoset. We tested five mated pairs of common marmosets in an inequity paradigm. Monkeys each completed 20 target tasks in order to receive a food reward. Animals either received the same reward (equity control) or different rewards than their partners’ (inequity test). Monkeys also completed two control conditions, one in which better food rewards were initially shown, but a less preferred food was given as the reward (to control for individual contrast) and a second in which different rewards were given in the absence of a task. Marmosets never refused food rewards. A Friedman’s test based on preliminary results found no variation between the three task-based conditions (X2(2)=1.135, p=0.567), indicating that marmosets are not sensitive to either inequity or individual contrast. Close social bonds between mates may reduce tension and thus limit responses to inequity in cooperative breeders.