@article {333817, title = {Reassuring body contact promotes social tolerance in bonobos and chimpanzees}, journal = {Proceedings of the Royal Society B: Biological Sciences}, volume = {293}, year = {2026}, month = {2026/07/01}, abstract = {

Social tolerance underpins cooperation in humans and other social animals, but its proximate drivers in short-term, competitive contexts remain poorly understood. Reassurance behaviours may enable individuals to pre-empt conflict and signal benign intent, facilitating social tolerance. We tested whether reassuring body contact during anticipation of a collective feeding event promotes cofeeding tolerance in our closest primate relatives. Using a controlled cofeeding paradigm across five semi-wild bonobo and chimpanzee groups (n\ = 116 individuals), we quantified pre-feeding affiliative contact and measured access to a restricted, depleting food zone. In both species, increased affiliative body contact enhanced subsequent cofeeding tolerance in most groups. Bonobo female\–female pairs and chimpanzee male\–male pairs engaged in more pre-feeding reassurance than other-sex pairings, aligning with species-specific predictions. However, these trends were only clear for socially tolerant groups. Likewise, vulnerable chimpanzee-specific kissing behaviours were more prevalent in a tolerant group. Our results reveal that reassuring contact may function as a flexible, short-term mechanism to mitigate contest competition and promote group-level tolerance. By identifying a proximate behavioural tool for managing competition in our closest cousins, our findings demonstrate the important role that friendly social behaviours play in negotiating the trade-off between competition and cooperation, as is essential to our own species\’ survival.

}, isbn = {1471-2954}, doi = {http://dx.doi.org/10.1098/rspb.2025.3190}, url = {https://royalsocietypublishing.org/rspb/article/293/2075/20253190/482572/Reassuring-body-contact-promotes-social-tolerance}, author = {Brooker, Jake S. and Goldsborough, Zo{\"e} and van Leeuwen, Edwin J. C. and Kordon, Stephanie and Webb, Christine E. and Clay, Zanna} }