Ekman refers to Paul Ekman, an American psychologist known for his work on emotions and facial expressions. He developed the theory that certain facial expressions are universal across cultures, meaning people from different backgrounds can recognize emotions like happiness, sadness, and anger through facial cues. His research has significantly influenced psychology, anthropology, and even law enforcement. Ekman's work led to the creation of the Facial Action Coding System (FACS), a comprehensive tool for categorizing facial movements. This system is used in various fields, including psychology, animation, and security, to analyze and interpret human emotions and nonverbal communication effectively.