TY - JOUR TI - Oxytocin promotes coordinated out-group attack during intergroup conflict in humans AU - Zhang, Hejing AU - Gross, Jörg AU - De Dreu, Carsten AU - Ma, Yina A2 - Mason, Peggy A2 - Behrens, Timothy E VL - 8 PY - 2019 DA - 2019/01/25 SP - e40698 C1 - eLife 2019;8:e40698 DO - 10.7554/eLife.40698 UR - https://doi.org/10.7554/eLife.40698 AB - Intergroup conflict contributes to human discrimination and violence, but persists because individuals make costly contributions to their group’s fighting capacity. Yet how group members effectively coordinate their contributions during intergroup conflict remains poorly understood. Here we examine the role of oxytocin for (the coordination of) contributions to group attack or defense in a multi-round, real-time feedback economic contest. In a double-blind placebo-controlled study with N=480 males in an Intergroup Attacker-Defender contest game, we found that oxytocin reduced contributions to attack and over time increased attacker’s within-group coordination of contributions. However, rather than becoming peaceful, attackers given oxytocin better tracked their rival’s historical defense and coordinated their contributions into well-timed and hence more profitable attacks. Our results reveal coordination of contributions as a critical component of successful attacks and subscribe to the possibility that oxytocin enables individuals to contribute to in-group efficiency and prosperity even when doing so implies outsiders are excluded or harmed. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter). KW - intergroup conflict KW - oxytocin KW - group coordination KW - out-group attack KW - collective contribution JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -