Theories of Collective Behavior A. Contagion Theories Contagion theories argue that human beings revert to herd-like behavior when they get together in large crowds . People in crowds mill about, like a group of animals, stimulating and goading one another into movement (Appelbaum and Chambliss, 1997:423). The acts of individuals are copied by other individuals. A skilled leader can manipulate crowds. B. Emergent-Norm Theories Emergent-norm theories suggest that it is values and norms , and not unconscious process, thatprompt groups of people to act in unison . Emergent-norm theories argue that even in seemingly chaotic crowd behavior, norms emerge that explains a crowd’s actions . While it may appear to an observer that the group is acting in a single purpose, the individuals within the crowd may have differing reasons for taking part (Appelbaum and Chambliss, 1997:424). XII. Forms of Collective Behavior A. Riots A riot is a prolonged outbreak of violent behavior by a large group of people that is directed against people and property . They are spontaneous, but are motivated by a conscious set of concerns. During a riot conventional norms are suspended and replaced by other norms developed by the group (Appelbaum and Chambliss, 1997:425). B. Fads and Fashion 1. Fads Fads are temporary, highly imitated outbreaks of mildly unconventional behavior (Appelbaum and Chambliss, 1997:425). Fads can include "the grunge look," wearing Levis with holes in the knees, or cramming people into a phone booth. 2. Fashion A fashion is a somewhat long-lasting style of imitative behavior or appearance . (Appelbaum and Chambliss, 1997:425). A fashion reflects a tension between people's desires to be different and their desire to conform. It's very success undermines its attractiveness, so the eventual fate of all fashions is to become unfashionable.