Abstract # 8033 Poster # 11:

Scheduled for Saturday, August 26, 2017 06:00 PM-08:00 PM: (National Ballroom AB) Poster Presentation


MEASURING AFFECTIVE RESPONSES TO INEQUITY IN CAPTIVE CHIMPANZEES (PAN TROGLODYTES), ORANGUTANS (PONGO ABELII) AND CAPUCHIN MONKEYS (CEBUS APELLA)

K. L. Leverett, M. Benitez and S. F. Brosnan
Georgia State University, Department of Psychology, P.O. Box 5010, Atlanta, GA 30302, USA
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     Inequity aversion is well documented in humans. Even young children show a negative behavioral reaction to inequity, despite accepting the lesser reward. Some non-human primates (NHPs) also show inequity aversion, but not all. One possible explanation is that in NHPs, reactions are operationalized as refusal to complete a task or accept a food reward, but this is costly, and like children, primates may notice inequity even when they do not refuse. To explore this, we coded video tapes of three species of NHPs (seven pairs of chimpanzees, four pairs of orangutans and three pairs of capuchin monkeys) for differences in levels of arousal (i.e., pacing, threats, banging) as a proxy for negative affect. We coded video tapes of the species on three conditions: inequity, equity control and individual contrast. We found that levels of arousal did vary. Capuchin subjects showed increased arousal in the inequity condition (z=-1.33, p=0.04) compared to the contrast and equity conditions. Interestingly, chimpanzee subjects showed the opposite pattern, with increased arousal in the equity condition (z=2.46, p=0.014). Consistent with their lack of refusals, orangutan subjects showed little variation across the conditions. These results indicate complex relationship between noticing inequity and refusals.