December 29, 2008

Facial Expressions Linked To Genes, Not Learned

In a new study that compared the facial expressions of blind and sighted athletes, researchers found that facial expressions are actually innate responses, rather than learned from watching others.

Researchers said this suggests that expressions could be deeply rooted in human evolution, they reported in the Journal of Personality and Social Psychology.

The study is the first of its kind to demonstrate that sighted and blind individuals use the same facial expressions, producing the same facial muscle movements in response to specific emotional stimuli.

David Matsumoto, a San Francisco State University psychology professor, studied the facial responses of sighted and blind judo athletes at the 2004 Summer Olympics and Paralympic Games. More than 4,800 photographs were captured and analyzed, including images of athletes from 23 countries.

"The statistical correlation between the facial expressions of sighted and blind individuals was almost perfect," Matsumoto said. "This suggests something genetically resident within us is the source of facial expressions of emotion."

"Losers pushed their lower lip up as if to control the emotion on their face and many produced social smiles - individuals blind from birth could not have learned to control their emotions in this way through visual learning, so there must be another mechanism," Matsumoto said.

"It could be that our emotions, and the systems to regulate them, are vestiges of our evolutionary history. It's possible that in response to negative emotions, humans have developed a system that closes the mouth so that they are prevented from yelling, biting or throwing insults."


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