When you were an adolescent, did your mother ever tell you, “Smile if you are in a bad mood, it will cheer you up.”? Or perhaps your mother told you to smile when you talk on the phone, as smiling will make you sound happier?
Well... she was right!
Some very comprehensive reviews of scientific literature have concluded that facial actions influence emotions. (Adelmann & Zajonc, 1989 Manstead, 1988.) If you think about it, we all know the inverse is true as well - emotions can be read from facial expressions. For example, do you know when your one year old child is happy, sad, frightened or surprised? How do you know this? Facial expressions are powerful sources of social information and these facial expressions enable individuals to quickly infer the feelings and intentions of others, including the liking and approval expressed by happy expressions or the hostility expressed by angry expressions (Keltner, Ekman, Gonzaga & Beer, 2003.)
Researchers studying emotions and their relationship to facial expression trace their inspiration to Charles Darwin. In 1872, Darwin published , in which he argued that all humans, and even other animals, show emotion through remarkably similar behaviors. For Darwin, emotion had an evolutionary history that could be traced across cultures and species—an unpopular view at the time. Today, many psychologists agree that certain emotions are universal to all humans, regardless of age, sex or culture.
Darwin’s work also lead to the development of the Facial Action Coding System, created by Paul Ekman and Wallace V. Friesen in 1978, to taxonomize human facial expressions. This system is a common standard to systematically categorize the physical expression of emotions, and it has proven useful to psychologists, law enforcement and animators.
The contribution Darwin has made to our modern world expands well beyond our current views of biology. His work in experimental psychology has shaped how your mom raised you and how researchers today study emotion.