In intergroup competition and conflict, humans benefit from coalitions with strong partners who help them to protect their in-group and prevail over competing out-groups. Here, we link oxytocin, a neuropeptide produced in the hypothalamus, to ally selection in intergroup competition. In a double-blind placebocontrolled experiment, males self-administered oxytocin or placebo, and made selection decisions about six high-threat and six low-threat targets as potential allies in intergroup competition. Males given oxytocin rather than placebo viewed high-threat targets as more useful allies and more frequently selected them into their team than low-threat targets.

Coalition formation, Decision-making, Hormones, Person perception
dx.doi.org/10.1098/rspb.2011.1444, hdl.handle.net/1765/37901
ERIM Top-Core Articles
Proceedings of the Royal Society B: Biological Sciences
Erasmus Research Institute of Management

de Dreu, C.K.W, Greer, L.L, Handgraaf, M.J.J, Shalvi, S, & van Kleef, G.A. (2012). Oxytocin modulates selection of allies in intergroup conflict. Proceedings of the Royal Society B: Biological Sciences, 279(1731), 1150–1154. doi:10.1098/rspb.2011.1444