The Facial Action Coding System (FACS)

The Facial Action Coding System (FACS) is a comprehensive tool used to categorize and describe facial movements based on the muscles involved. Developed by researchers Paul Ekman and Wallace V. Friesen, FACS breaks down facial expressions into specific "action units" corresponding to different facial movements. This system helps in understanding emotions and social cues, as each expression can convey different feelings like happiness, sadness, or anger. FACS is commonly used in psychology, animation, and even security to analyze human emotions and improve interactions by decoding the subtle signals our faces communicate.