This document summarizes reasons why people join groups, how they act within groups, and why they stay in groups. It discusses Maslow's hierarchy of needs and Schutz's theory of fundamental interpersonal relationships as explanations for why people join groups. It describes different member roles, levels of confidence, and degrees of assertiveness. Motivations for staying in groups include fulfilling needs, having a sense of meaning, choice, competence, and progress. The document also covers assessment, feedback, rewards, and punishment.