Abstract

Research suggests the experimental manipulation of oxytocin facilitates positive interactions, cooperation and trust. The mechanism by which oxytocin influences social behavior is not well understood. We explored the hypothesis that oxytocin alters how people perceive themselves, which could be one mechanism by which oxytocin promotes prosocial behavior. In a between-subject, randomized, and double-blind experiment, 100 university students received a 24 I.U. dose of intranasal oxytocin or placebo, and then completed the Revised NEO Personality Inventory (NEO-PI-R) and other self-report measures 90 minutes later. Intranasal oxytocin increased ratings of NEO-PI-R extraversion and openness to experiences (F(1,98) = 4.910, p = .025, partial η2 = .05; F(1,98) = 6.021, p = .016, partial η2 = .06), particularly for the following facets: positive emotions (d = 0.48, p < .05), warmth (d = 0.47, p < .05), openness to values (d = 0.45, p < .05) and ideas (d = 0.40, p < .05), trust (d = 0.44, p < .05) and altruism (d = 0.40, p < .05). Oxytocin had no influence on ratings of negative emotionality, conscientiousness, rejection sensitivity, depression, worry, self-esteem, and perceived social support. The administration of oxytocin improved participants’ self-perceptions of their personality, at least for certain traits important for social affiliation. Increased positive self-referential processing may be one mechanism by which oxytocin promotes positive social behaviors.