Background: Oxytocin is a neuropeptide that is associated with increased trust. Perceptions of trustworthiness are associated with detection of positive facial affect, which suggests that oxytocin may enhance the recognition of positive facial affect. The present study tests this hypothesis.
Methods: A double-blind, between-groups design was used, with 50 volunteers randomly assigned to receive intranasally administered oxytocin or placebo. Thirty-five minutes following the administration of oxytocin or placebo, participants identified anger, disgust, fear, happiness, sadness, and surprise expressions that were morphed with neutral faces such that they varied from 10% to 100% intensity.
Results: Oxytocin significantly and specifically improved the recognition of happy facial expressions; no significant differences in recognition of other expression were found. The improvement was not associated with gender, response biases, or changes in mood, and it was most pronounced for subtle expressions.
Conclusions: Acute oxytocin administration enhances healthy adults' ability to accurately identify positive emotional facial expressions. These findings reinforce oxytocin's role in facilitating affiliative interactions and have implications for the treatment of conditions that are marked by social affiliation deficits.