title: Oxytocin modulates third-party sanctioning of selfish and generous behavior within and between groups.
abstract: Human groups function because members trust each other and reciprocate cooperative contributions, and reward others' cooperation and punish their non-cooperation. Here we examined the possibility that such third-party punishment and reward of others' trust and reciprocation is modulated by oxytocin, a neuropeptide generally involved in social bonding and in-group (but not out-group) serving behavior. Healthy males and females (N=100) self-administered a placebo or 24 IU of oxytocin in a randomized, double-blind, between-subjects design. Participants were asked to indicate (incentivized, costly) their level of reward or punishment for in-group (outgroup) investors donating generously or fairly to in-group (outgroup) trustees, who back-transferred generously, fairly or selfishly. Punishment (reward) was higher for selfish (generous) investments and back-transfers when (i) investors were in-group rather than outgroup, and (ii) trustees were in-group rather than outgroup, especially when (iii) participants received oxytocin rather than placebo. It follows, first, that oxytocin leads individuals to ignore out-groups as long as out-group behavior is not relevant to the in-group and, second, that oxytocin contributes to creating and enforcing in-group norms of cooperation and trust.
authors.affiliation: School of Psychology, Cardiff University, Cardiff CF10 3AT, United Kingdom.
authors.forename: Katie
authors.initials: K
authors.lastname: Daughters
authors.affiliation: School of Psychology, Cardiff University, Cardiff CF10 3AT, United Kingdom.
authors.forename: Antony S R
authors.initials: ASR
authors.lastname: Manstead
authors.affiliation: Department of Psychology, University of Amsterdam, 1018 WB Amsterdam, The Netherlands.
authors.forename: Femke S
authors.initials: FS
authors.lastname: Ten Velden
authors.affiliation: Center for Experimental Economics and Political Decision Making (CREED), University of Amsterdam, 1018 WB Amsterdam, The Netherlands; Social and Organizational Psychology, Leiden University, 2300 RB Leiden, The Netherlands. Electronic address: c.k.w.dedreu@fsw.leidenuniv.nl.
authors.forename: Carsten K W
authors.initials: CKW
authors.lastname: De Dreu
mesh_terms: D000293:Adolescent; D000328:Adult; D000533:Altruism; D004311:Double-Blind Method; D005260:Female; D006126:Group Processes; D006801:Humans; D007600:Judgment / Q000187:drug effects*; D008297:Male; D010121:Oxytocin / Q000008:administration & dosage*; D012929:Psychological Distance; D011678:Punishment; D012201:Reward; D055815:Young Adult
chemical_list: D010121:Oxytocin
keywords: Competition; Economic games; Endocrinology; Oxytocin; Parochial altruism