The document discusses group norms and how they develop and strengthen within groups. It states that norms summarize and simplify expected group behaviors, only apply to overt actions, develop gradually, and do not equally apply to all group members. Norms form to help groups survive, increase predictability of behaviors, reduce embarrassment, and express the group's central values. Norm strength is impacted by the intensity of feelings when norms are violated and the level of agreement on appropriate behaviors. High group cohesion and an emphasis on performance norms typically leads to the highest group performance levels.