Oxytocin promotes intuitive rather than deliberated cooperation with the in-group.
A contribution to a special issue on Hormones and Human Competition. In intergroup settings, individuals prefer cooperating with their in-group, and sometimes derogate and punish out-groups. Here we replicate earlier work showing that such in-group bounded cooperation is conditioned by oxytocin and extend it by showing that oxytocin-motivated in-group cooperation is intuitive rather than deliberated. Healthy males (N=65) and females (N=129) self-administered intranasal placebo or 24IU oxytocin in a double-blind placebo-controlled between-subjects design, were assigned to a three-person in-group (that faced a 3-person out-group), and given an endowment from which they could contribute to a within-group pool (benefitting the in-group), and/or to a between-group pool (benefitting the in-group and punishing the out-group). Prior to decision-making, participants performed a Stroop Interference task that was either cognitively taxing, or not. Cognitively taxed individuals kept less to themselves and contributed more to the within-group pool. Furthermore, participants receiving placebo contributed more to the within-group pool when they were cognitively taxed rather than not; those receiving oxytocin contributed to the within-group pool regardless of cognitive taxation. Neither taxation nor treatment influenced contributions to the between-group pool, and no significant sex differences were observed. It follows that in intergroup settings (i) oxytocin increases in-group bounded cooperation, (ii) oxytocin neither reduces nor increases out-group directed spite, and (iii) oxytocin-induced in-group cooperation is independent of cognitive taxation and, therefore, likely to be intuitive rather than consciously deliberated.
University of Amsterdam, Work and Organizational Psychology, The Netherlands.
Femke S
FS
Ten Velden
Cardiff University, School of Psychology, United Kingdom.
Katie
K
Daughters
Leiden University, Social and Organizational Psychology, The Netherlands; University of Amsterdam, Center for Experimental Economics and Political Decision Making, The Netherlands. Electronic address: c.k.w.de.dreu@fsw.leidenuniv.nl.
Carsten K W
CKW
De Dreu
D000281:Administration, Intranasal; D000293:Adolescent; D000328:Adult; D003299:Cooperative Behavior; D003657:Decision Making / Q000187:drug effects*; D004311:Double-Blind Method; D005260:Female; D006126:Group Processes; D006801:Humans; D007398:Interpersonal Relations; D008297:Male; D009042:Motivation; D010121:Oxytocin / Q000494:pharmacology*; D012737:Sex Factors; D055815:Young Adult
D010121:Oxytocin
Dual systems; In-group cooperation; Intergroup settings; Neuroendocrinology