A meta-analysis of hormone administration effects on cooperative behaviours: Oxytocin, vasopressin, and testosterone

The hormones oxytocin, vasopressin, and testosterone have been implicated in cooperative behaviours and have attracted increasing research interest for their potential to regulate human cooperation in both healthy and clinical populations. However, the behavioural effects of the administration of these hormones remain to be verified. The current analysis included 41 studies involving 3,269 participants with a narrow age range. We examined the administration effects of these hormones on cooperative behaviour and the regulatory effects of individual characteristics, hormone interventions, and task structure and context. Results revealed a moderate positive effect size of oxytocin intranasal administration, a large negative effect size of vasopressin intranasal administration, and nonsignificant effects of testosterone administration on cooperative behaviours. Participants with mental dysfunctions were less sensitive to oxytocin and vasopressin administration. Oxytocin administra-tion was effective in an in-group situation and for initial choices, corroborating a Tit-for-Tat strategy.

Automated summary

The study found that intranasal administration of oxytocin had a moderate positive effect size, while intranasal administration of vasopressin had a large negative effect size, and administration of testosterone had no significant impact on cooperative behaviors. Participants with mental dysfunctions were less sensitive to oxytocin and vasopressin administration, and oxytocin administration was effective in in-group situations and for initial choices.