Have you ever noticed how, when two people are talking, they seem to mimic each other's facial expressions?
Some psychologists say this is simply a case of emotions being contagious. However, others go further, arguing this mimicry plays a functional role; that by copying someone else's facial expression it helps us to better understand how they are feeling.
Now Lindsay Oberman and colleagues have tested the idea that if mimicry really does play a functional role, then disrupting our ability to mimic should interfere with our recognition of other people's facial expressions.
And that's exactly what they found when twelve students were asked to categorise morphed photographs of people's faces showing varying degrees of happiness, sadness, fear or disgust.
To disrupt their ability to mimic, the students clenched a pen between their teeth, an act that exercises many of the muscles needed to perform facial expressions. This significantly impaired the students' ability to correctly identify happiness, and to some extent also their ability to identify disgust. The identification of sadness and fear was unaffected, perhaps because these emotions are expressed less through the facial musculature and more through body posture and tone of voice. By contrast a happy expression is known to involve many facial muscles.
A control condition in which the students held a pen lightly between their lips (no use of face muscles) did not interfere with recognition of facial expression. Neither did chewing gum, which involves the facial muscles only intermittently.
“Our findings are consistent with the proposal that people's ability to understand emotions in others involves simulating their states,” the researchers said.
Oberman, L.M., Winkielman, P. & Ramachandran, V.S. (2007). Face to face: Blocking facial mimicry can selectively impair recognition of emotional expressions. Social Neuroscience, 2, 167-178.
More on emotion and face recognition from the Digest:
Link to related Digest item showing violent video games slow our recognition of happy faces.
Link to related Digest item showing cryptic crosswords impair face recognition.
Link to related Digest item showing we're better at recognising the emotions of people we identify with.