This document summarizes key concepts from Chapter 13 of Myers' Psychology textbook regarding emotion. It discusses several theories of emotion including the James-Lange Theory, Cannon-Bard Theory, and Schachter's Two-Factor Theory. It also covers the physiology of emotion, how arousal relates to performance, and research on expressed emotion through facial expressions and lie detection polygraphs. Happiness and experienced emotion are examined through concepts like subjective well-being, adaptation-level phenomenon, and factors found to correlate with happiness like relationships, work satisfaction, and health behaviors.