The main idea of Sigmund Freud's crowd behavior theory is that people who are in a crowd act differently towards people than those who are thinking individually. The minds of the group would merge together to form a way of thinking. Each member's enthusiasm would be increased as a result, and one becomes less aware of the true nature of one's actions. Le Bon’s idea that crowds foster anonymity and sometimes generate emotion has become somewhat of a cliché. Yet, it has been contested by some critics, such as Clark McPhail who points out that some studies show 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.
However, it must be noted that if Le Bon often referred to the cliché of the irrational crowd, which was current in the 19th century and before (in particular in the fields of criminology, which tended to describe crowds as irrational and criminal groups), he considered himself the founder of "crowd psychology". Thus, he didn't consider crowds as totally irrational, but simply thought that ordinary individualist psychology wasn't relevant to this phenomenon. Le Bon was a pioneer in propaganda, which he considered a suitable and rational technique for managing groups, using for example communal reinforcement of beliefs, etc. Le Bon's 1895 The Crowd: A Study of the Popular Mind influenced many 20th century figures, including Adolf Hitler, whose Mein Kampf insisted on Le Bon's work.
Wilfred Trotter, an English surgeon, wrote similarly, becoming famous for his book Instincts of the Herd in Peace and War. He introduced Wilfred Bion with whom he lived and worked, to the ideas of Sigmund Freud, and would later become personal physician to Freud. Wilfred Bion, and Ernest Jones, who also worked for Trotter, became influential figures in the British Psychoanalytic movement, and Bion who wrote a collection of papers on Experiences in Groups said that he was much influenced by Trotter.
Sigmund Freud would criticize Le Bon's concept of "collective soul", comparing it to the collective unconscious, asserting that crowds do not have a soul of their own, nor do specific ethnic groups have a Volkgeist. Rather, individuals identify themselves to their leaders through their own "ideal ego" (that is, their subjective representation of their leader). The Freudian concept of an "ideal ego" later became the super-ego. Ultimately, leaders themselves identify themselves to an idea.
Theodor Adorno criticized the belief in a spontaneity of the masses: according to him, the masses were an artificial product of "administrated" modern life. The Ego of the bourgeois subject dissolved itself, giving way to the Id and the "de-psychologized" subject. Furthermore, the bond linking the masses to the leader through the spectacle, as fascism displayed in its public representations, is feigned: "When the leaders become conscious of mass psychology and take it into their own hands, it ceases to exist in a certain sense... Just as little as people believe in the depth of their hearts that the Jews are the devil, do they completely believe in their leader. They do not really identify themselves with him but act this identification, perform their own enthusiasm, and thus participate in their leader's performance... It is probably the suspicion of this fictitiousness of their own 'group psychology' which makes fascist crowds so merciless and unapproachable. If they would stop to reason for a second, the whole performance would go to pieces, and they would be left to panic.
Edward Bernays (1891 – 1995), nephew of psychoanalyst Sigmund Freud, was considered the father of the field of public relations. Bernays was one of the first to attempt to manipulate public opinion using the psychology of the subconscious. He felt this manipulation was necessary in society, which he felt was irrational and dangerous.
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 states that there is no homogeneous activity within a repetitive 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.
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 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, followed by others. 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. Each Member in the crowd plays a significant role.