%0 Journal Article %A Radovanović, Kia %A Lorskens, Anoek %A Schütte, Sebastian %A Bräuer, Juliane %A Call, Josep %A Haun, Daniel B. M. %A Van Leeuwen, Edwin J. C. %+ Department of Comparative Cultural Psychology, Max Planck Institute for Evolutionary Anthropology, Max Planck Society Department of Comparative Cultural Psychology, Max Planck Institute for Evolutionary Anthropology, Max Planck Society Department of Comparative Cultural Psychology, Max Planck Institute for Evolutionary Anthropology, Max Planck Society %T Bonobos respond aversively to unequal reward distributions : %G eng %U https://hdl.handle.net/21.11116/0000-0011-0FF7-7 %R 10.1098/rspb.2024.2873 %7 2025-04-16 %D 2025 %8 16.04.2025 %* Review method: peer-reviewed %X Inequity aversion (IA) is the resistance to unequitable rewards given
similar investments. It has been postulated as an important mechanism
by which human cooperation thrives. To understand the evolutionary
origin of human IA and its distribution across the animal kingdom, many
species have been tested on IA, with mixed results. Whereas chimpanzees
were originally found to show IA, more recent studies showed that their
IA response could be explained by social disappointment. We conducted
two studies on IA in bonobos using established paradigms: a token-
exchange task and the social disappointment task. Bonobos could exchange
tokens for equal or less-preferred food rewards than their partners (Study
1) and were tested with humans and machines to control for social
disappointment effects (Study 2). We found that bonobos responded
aversively to unequal food distributions in both studies, which was
reflected by more refusals to participate when disadvantaged. Notably,
and contrary to chimpanzees, this effect could not be explained by social
disappointment, although Study 2 was only partially consistent with an
IA explanation. Overall, our findings indicate that bonobos possess the
sensitivity to recognize and respond to unfair treatment, which supports
the notion that IA may have coevolved as a stabilizing mechanism for
cooperation. %K bonobo, inequity aversion, cooperation, sociality, comparative psychology, abstract %J Proceedings of the Royal Society of London. Series B: Biological Sciences (London) %V 292 %N 2045 %] 20242873 %@ 0962-8452