In the Journal of Personality and Social Psychology paper, David Matsumoto of San Francisco State University and Bob Willingham of the Center for Psychological Studies in Berkeley, Calif., present the results of the first study ever conducted comparing the facial expressions of blind people with those of sighted people in a natural, nonlaboratory setting. Those studied were all judo athletes- blind ones who competed in the 2004 Paralympic Games in Athens and sighted ones who competed in the 2004 Olympics in the same competition hall a few weeks earlier. Matsumoto conceived the paper to investigate one of the oldest dilemmas in the study of physiology. We have known for many years that people all over the world, even those from remote cultures, use the same facial expressions to convey basic emotions like grief or joy. Charles Darwin noted this phenomenon in the 19th century, and Matsumoto's mentor, a famous psychologist named Paul Ekman who traveled the globe in the 1960s, proved that both isolated tribesmen and urban Westerners identified pictures of facial expressions in the same way. Ekman demonstrated that a frown means unhappiness the world over; wide eyes mean fright or surprise; a wrinkled nose means disgust. But no one has yet found the source of these universal expressions: Do we all learn the expressions through our culture, or are facial configurations genetically coded for everyone?
The possibility that your expression could affect your mood was first suggested to me by Marsha Linehan, a University of Washington psychologist who treats suicidal patients. She has found that helping patients modulate their facial expressions- relaxing the face when angry, for instance- can help them control their emotions. Ekman and his colleagues provided evidence of this in a Science paper back in 1983. They found that those instructed to produce certain facial movements showed the same physiological responses as those asked to recall a highly emotional experience. Later, a study showed that if you hold a pencil between your teeth- causing your mouth to approximate a smile- it will be easier for you to find cartoons funny.
In short, the emotional train does run in two directions: between your brain, which may be screaming from the pain that your trainer is causing, and your face, which can- if you draw it into a relaxed expression- inform your brain that it shouldn't be protesting so much. So next time you're working out and grimacing, push your facial muscles into submission. Look blank. You will find it's easier to get through one more rep.”