Oxytocin reactivity during intergroup conflict in wild chimpanzees
Intergroup conflict is evident throughout the history of our species, ubiquitous across human societies, and considered crucial for the evolution of humans’ large-scale cooperative nature. Like humans, chimpanzee societies exhibit intragroup coordination and coalitionary support during violent inter...
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Published in | Proceedings of the National Academy of Sciences - PNAS Vol. 114; no. 2; pp. 268 - 273 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
National Academy of Sciences
10.01.2017
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Series | From the Cover |
Subjects | |
Online Access | Get full text |
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Summary: | Intergroup conflict is evident throughout the history of our species, ubiquitous across human societies, and considered crucial for the evolution of humans’ large-scale cooperative nature. Like humans, chimpanzee societies exhibit intragroup coordination and coalitionary support during violent intergroup conflicts. In both species, cooperation among group members is essential for individuals to gain access to benefits from engaging in intergroup conflict. Studies suggest that a contributive mechanism regulating in-group cooperation during intergroup conflicts in humans involves the neuropeptide hormone oxytocin, known to influence trust, coordination, and social cognition, although evidence from natural settings is lacking. Here, applying a noninvasive method, we investigate oxytocinergic system involvement during natural intergroup conflicts in wild chimpanzees. We found that chimpanzees of both sexes had significantly higher urinary oxytocin levels immediately before and during intergroup conflict compared with controls. Also, elevated hormone levels were linked with greater cohesion during intergroup conflicts, rather than with the level of potential threat posed by rival groups, intragroup affiliative social interactions, or coordinated behavior alone. Thus, the oxytocinergic system, potentially engendering cohesion and cooperation when facing an out-group threat, may not be uniquely human but rather a mechanism with evolutionary roots shared by our last common ancestor with chimpanzees, likely expediting fitness gains during intergroup conflict. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Author contributions: L.S., T.D., C.C., and R.M.W. designed research; L.S. and A.P. performed research; L.S., A.P., R.M., C.C., and R.M.W. analyzed data; and L.S., T.D., C.C., and R.M.W. wrote the paper. 2C.C. and R.M.W. contributed equally to this work. Edited by Dorothy L. Cheney, University of Pennsylvania, Philadelphia, PA, and approved December 1, 2016 (received for review October 12, 2016) |
ISSN: | 0027-8424 1091-6490 |
DOI: | 10.1073/pnas.1616812114 |