Crowd psychology

Ordinary people typically can gain direct power by acting collectively. Historically, because large groups of people have been able to effect dramatic and sudden social change, in a manner that bypasses established due process, they have also provoked controversy. The collective action that some people condemn, others support. Social scientists have developed several different theories for explaining crowd psychology, and the ways in which the psychology of the crowd differs significantly from the psychology of those individuals within it.

Contagion theory
An early explanation of collective behavior was formulated by French sociologist Gustave Le Bon. According to Le Bon’s contagion theory, crowds exert a hypnotic influence over their members. Shielded by the anonymity of a crowd, people abandon personal responsibility and surrender to the contagious emotions of the crowd. A crowd thus assumes a life of its own, stirring up emotions and driving people toward irrational, perhaps violent, action.

Le Bon’s idea that crowds foster anonymity and sometimes generate emotion is surely true. Yet, as Clark McPhail points out, systematic research reveals that "the madding crowd" does not take on a life of its own, apart from the thoughts and intentions of members. Norris Johnson, after investigating a panic at a 1979 Who concert concluded that the crowd was composed of many small groups of people mostly trying to help each other.

Convergence theory
Convergence theory holds that crowd behavior is not a product of the crowd itself, but is carried into the crowd by particular individuals. Thus, crowds amount to a convergence of like-minded individuals. In other words, while contagion theory states that crowds cause people to act in a certain way, convergence theory says the opposite: that people who wish to act in a certain way come together to form crowds.

An example of convergence theory is the practice sometimes observed when an immigrant population becomes common in a previously homogeneous area, and members of the existing community (apparently spontaneously) band together to threaten those trying to move into their neighborhoods. In such cases, convergence theorists contend, the crowd itself does not generate racial hatred or violence; rather, the hostility has been simmering for some time among many local people. A crowd then arises from convergence of people who oppose the presence of these neighbors. Convergence theory claims that crowd behavior as such is not irrational; rather, people in crowds express existing beliefs and values so that the mob reaction is the rational product of widespread popular feeling.

Emergent-norm theory
Ralph Turner and Lewis Killian developed the emergent-norm theory of crowd dynamics. These researchers concede that social behavior is never entirely predictable, but neither are crowds as irrational. If similar interests may draw people together, distinctive patterns of behavior may emerge in the crowd itself. Crowds begin as collectivities, acting, and protest crowds – norms may be vague and changing as when, say, one person at a rock concert holds up a lit cigarette lighter to signal praise for the performers, and other follow suit. In short, people in crowds make their own rules as they go along.

Decision-making, then, plays a major role in crowd behavior, although casual observers of a crowd may not realize it. Crowd behavior reflects the desires of participants, but it is also guided by norms that emerge as the situation unfolds. Emergent-norm theory points out that people in a crowd take on different roles. Some step forward as leaders; others become lieutenants, rank-and-file followers, inactive bystanders or even opponents.