The term "collective behavior" was first used by Robert E. Park, and employed definitively by Herbert Blumer, to refer to social processes and events which do not reflect existing social structure (laws, conventions, and institutions), but which emerge in a "spontaneous" way.

Collective behavior might also be defined as action which is neither conforming (in which actors follow prevailing norms) nor deviant (in which actors violate those norms). Collective behavior, a third form of action, takes place when norms are absent or unclear, or when they contradict each other. Scholars have devoted far less attention to collective behavior than they have to either conformity or deviance.