Rationale: 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.
Objective: We explored the hypothesis that oxytocin alters how people perceive themselves, which could be one mechanism by which oxytocin promotes prosocial behavior.
Method: 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 min later.
Results: Intranasal oxytocin increased ratings of NEO-PI-R extraversion and openness to experiences [F(1,98) = 4.910, p = .025, partial η (2) = .05; F(1,98) = 6.021, p = .016, partial η (2) = .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.
Conclusion: 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.