One of my favorite new books is
Blink: The Power of Thinking Without Thinking (affiliate link). It describes the many ways that our brains process information unconsciously, and how we make decisions based on those processes. One of the sources of this subconscious information is the arsenal of microexpressions we translate from other's faces. In the book, Malcolm Gladwell highlights the work of Paul Eckman and Wallace Friesen, two researchers who have mapped out The Facial Action Coding System, a system to codify microexpressions by describing the muscle movements that accompany each emotional expression. To create these "maps," they practiced making the faces for joy, exhilaration anger, sadness, etc., in front of mirrors and in front of each other. To their surprise, they found their emotional state was affected by what faces they spent the day making. On days they worked on anger or other less pleasant emotions, they felt angry, depressed, or other unpleasant feelings. On happier expression days, they felt uplifted.
