Oxytocin Plays A Role In Facial Mimicry

Whether functioning as a hormone or a neurotransmitter, oxytocin is involved in a series of important physiological and psychological functions. For example, it may promote maternal attachment, lactation, pair bonding and group cohesion.

But the picture is actually more complex; in some circumstances it can even lead to aggressive behavior.

Experimental results have also shown that intranasal administration of a spray of oxytocin makes people more willing to take care of others and better at recognizing emotions.

It was this latter effect that attracted the attention of Sebastian Korb, researcher at the International School for Advanced Studies (SISSA) in Trieste and expert on facial mimicry. What is the mechanism at the basis of the emotion recognition facilitation observed after the administration of intranasal oxytocin, Korb asked himself.

Embodied Cognition Theory

According to embodied cognition theory, the ability to imitate an emotional expression seen on the face of others facilitates the recognition of the emotion. Could oxytocin be stimulating the imitation?

To test the existence of a relationship between oxytocin and facial mimicry, Korb and colleagues selected a sample of 60 adult males and gave, in form of a spray, half the sample a dose of oxytocin and the other half a dose of placebo. The experiment was double blind, meaning that neither the experimenter nor the subject were aware of which product was administered.

After a sufficient time interval for the drug to take effect, the subjects underwent a series of tests assessing the evaluation and recognition of emotional expressions shown in a series of short videos depicting adult or infant faces. As they performed the tests, the response of their facial muscles was also recorded to measure facial mimicry.

The results showed that facial mimicry was more pronounced in the subject who received the oxytocin dose (compared to those who received the placebo), and that this increase in mimicry was greater when subjects observed newborns crying; note that anger and sadness are not easily distinguishable in very young infants.

“The finding is interesting not only because it shows that oxytocin has a modulating effect on facial mimicry, but also because there is a strong response to infant faces even in males, whereas effects of oxytocin on caregiving had typically been shown in women.”

It is also of interest, the authors write, since facial mimicry helps with recognition of emotions, and it is reduced in autism spectrum disorders (ASD). The findings suggest that oxytocin could potentially be given to individuals with ASD, to increase facial mimicry and improve emotion recognition. They caution that further studies are needed in a larger sample size of patients.

Sebastian Korb, Jennifer Malsert, Lane Strathearn, Patrik Vuilleumier, Paula Niedenthal
Sniff and mimic — Intranasal oxytocin increases facial mimicry in a sample of men
Hormones and Behavior, 2016; 84: 64 DOI: 10.1016/j.yhbeh.2016.06.003

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