In understanding crowd psychology and its explanation of conflict and violence, there are different theoretical approaches that turn on different understandings of communication processes. There are three models of communication in the crowd worth reviewing: classic, normative, and dynamic. Classic models suggest that crowd members are influenced by an idea of emotion presented to them. Normative models suggest that influence is constrained by what is seen as consonant with group norms. And, finally, dynamic models examine how that which becomes normative in the group depends upon intergroup relations. The last of these approaches can explain the patterned, socially meaningful and yet changing nature of crowd action. Crowd action, itself, is a form of communication because it serves to shape the social understandings of participants as well as the social understandings of those beyond the crowd. It is argued that the nature and centrality of crowds contribute to the understanding and creating of social relations in society.