Oxytocin facilitation of acceptance of social advice is dependent upon the perceived trustworthiness of individual advisors.

The neuropeptide oxytocin may increase social cohesion by making us more willing to trust others and/or to conform to their opinions. Here we investigated whether intranasal oxytocin can influence acceptance of advice given on solving everyday social problems by either individual expert (psychologist) or non-expert advisors with or without influencing their perceived likeability or trustworthiness. In a double-blind, between-subject, placebo-control design study in 160 male and female subjects, intranasal oxytocin (24IU) only significantly enhanced acceptance of advice given by female psychologists who were rated as the most trustworthy advisors. However, oxytocin itself did not alter either trustworthiness or likeability ratings. The oxytocin effect on acceptance of the female psychologist's advice was not maintained after a week, with subjects mainly reverting to their original solutions. These findings suggest that while oxytocin can transiently increase acceptance of advice from the most trustworthy individuals this is because it makes subjects more likely to conform to their opinions rather than enhancing their perceived trustworthiness or likeability. Thus in every day contexts oxytocin may primarily promote social cohesion by facilitating conformity towards the opinions of the most trusted individuals.