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Facial Expression

Darwin commented on the inborn emotional expressiveness of babies. Carroll Izard and colleagues at the University of Delaware identified 10 distinct facial expressions common in babyhood: interest, distress, disgust, joy, anger, surprise, shame, fear, contempt, and guilt.

Babies are also able to interpret facial expressions. Cohn & Tronick (1983) had mothers imagine how they felt on a day when they were tired. The mothers were instructed to look away from the baby, speak in a monotone, and turn the corners of their mouths down. The babies responded by crying, grimacing, and otherwise showing distress.

Ekman's Work on Facial Expression

Paul Ekman is a leading investigator of facial expression. He is famous for a coding system that identifies 80 distinct muscles in the face. This system provides a precise way to define facial expressions. That makes it a very useful tool for researchers who wish to make precise definitions of facial expressions.

What coding system did Ekman develop? Why is it useful for researchers?

How did some of Ekman's early work test Darwin's idea? Ekman investigated Darwin's belief that all humans interpret facial expressions the same way. He showed pictures of humans expressing the emotions of happiness, fear, surprise, anger, disgust, and sadness to people from cultures all over the world. People in different cultures all interpreted these expressions the same way. The expressions show anger, surprise, disgust (top row) then surprise, happiness, and sadness (bottom row).

Faces interpreted the same way by people in different cultures

What is an easy way to tell a sincere smile from a nervous or polite smile?

Using his system, Ekman could document the fact that there are at least four distinct smiles that do not necessarily convey happiness. One type, with a tense upper lip, masks anger. Another type, the insincere smile, lasts too long, for example 10 seconds, while a genuine smile is more likely to last 2 seconds. The insincere smile is frozen into place with the aid of clenched teeth.

A third type of smile is intended to cushion criticism. The lips are closed and the corners of the mouth are drawn upward. It is the type of smile a teacher might use when telling a student what is wrong with a term paper. The fourth smile is a "reluctant, compliant smile" of someone who is giving in to pressure from somebody else. It might be called a grim smile. The eyes are cast downward, the corners of the mouth are drawn sideways and slightly up (Goleman, 1984).

Ekman and Davidson (1993) reported that raised cheeks and "crow's feet" wrinkles around the eyes often accompany a truly happy smile. Non-happy smiles (such as the four types outlined above, are not accompanied by this raising of cheeks and wrinkling around the eyes.

What is Duchenne's marker?

Ekman found that a French neurologist, Duchenne de Boulogne, had previously reported this fact in 1862. Duchenne observed that "the emotion of frank joy" is expressed by pulling up the sides of the mouth, which "obeys the will," and by movement of the muscles around the eyes, which is "only put into play by the sweet emotions of the soul..." Ekman called the latter Duchenne's marker. Ekman and co-workers showed that Duchenne's marker could be easily observed in real time (without slowing down a video recording) and that it was indeed useful in distinguishing happy smiles from other types.

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