This document discusses the components and theories of emotion. It defines emotion as coming from the Latin word "emovere" meaning to move out. There are four components of emotion: cognitive, subjective, behavioral, and physiological. Theories discussed include the James-Lange theory stating emotion follows bodily changes, Cannon-Bard theory arguing physiological arousal and emotion occur simultaneously, and the facial feedback hypothesis proposing facial muscle movements produce or intensify emotions. Measurement of emotion can be done through physiological response, observation of behavior, and self-report.