Deindividuation Definition

Deindividuation theory was developed to explain the violence and irrationality of the crowd. How does a group of seemingly normal individuals become an unruly mob? According to deindividuation theory, the anonymity and excitement of the crowd make individuals lose a sense of individual identity. As a result, crowd members cease to evaluate themselves, and they become irrational and irresponsible. All of this makes the crowd fickle, explosive, and prone to anti-normative and disinhibited behavior.

But, despite a large amount of research, there is little support for deindividuation theory. Alternative approaches suggest that crowd behavior is not due to a loss of identity but to a transition to a collective (social) identity. The remainder of this entry outlines the theoretical evolution of deindividuation theory, summarizes the research to date, and highlights an alternative perspective.

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Theoretical Evolution of Deindividuation

DeindividuationDeindividuation theory can be traced back to some of the earliest works of social psychology. In his 1895 book La Foule (The Crowd), Gustave Le Bon described how the crowd psychologically transforms the psychology of its members. Anonymity, suggestibility, and contagion turn a gathering of individuals into a psychological crowd. The collective mind (dominated by primitive instincts rooted in our racial unconscious) takes possession of individuals. As a result, rational self-control ceases, and individuals become unthinking, fickle, and suggestible; that is, they become inferior forms of evolution. The individual submerged in the crowd thus becomes a mindless puppet capable of performing any act, however atrocious or heroic.

Although many have criticized Le Bon’s theory and his politics—the two are not unrelated—the influence of La Foule in science and society has been huge. His book is a scientific bestseller. But Le Bon was also controversial. He was popular with politicians of the right, including Benito Mussolini, Joseph Goebbels, and Adolf Hitler. Although one should not blame Le Bon for the atrocities of fascism, his writings did blend science with a shot of far-right politics. His analysis of the crowd was clouded by fears of communism and trade unionism; he also gave race a prominent place in his theory.

As a result of his politics, Le Bon is rarely credited for his contribution to social psychology. But when Leon Festinger, Albert Pepitone, and Theodore Newcomb coined the term deindividuation in 1952, they borrowed core ideas from Le Bon. Their starting point was Le Bon’s characterization of the crowd as irrational, disinhibited, and antinormative. What psychological process could explain this? The answer lay in the lack of accountability in the crowd, inducing a feeling among people in the crowd of being unaware of themselves. This process is called deindividuation.

Over the subsequent decades, deindividuation theory was developed and expanded. Interestingly, the psycho-logical process that deindividuation referred to gradually shifted. By the 1990s, deindividuation had become a loss of awareness of the self. But both aspects of what became known as deindividuation (lack of accountability and lack of self-awareness) were processes already identified by Le Bon.

In other ways, deindividuation theory did move away from Le Bon. The most important difference is that deindividuation is defined as an absence of individual identity. Le Bon argued that the crowd replaces individual identity by a collective mind. But the collective mind plays no role in deindividuation theory. In fact, deindividuation theory did not offer any systematic analysis of social influence to explain how the actions of the crowd were guided or controlled.

Deindividuation Research

In the 1970s, deindividuation became a popular area in group research. Many laboratory studies tested the pre-diction that anonymity leads to disinhibition. Often participants were dressed in uniforms or cloaks and hoods to render them anonymous, and they were placed in a situation where they could display aggressive or anti-normative behavior (as in the Stanley Milgram’s studies of obedience). Their actions were compared with a plain-clothed control group. Unfortunately for deindividuation theory, the empirical support was inconsistent. Overview articles written in 1977 and 1980 concluded that there was virtually no evidence for the psychological state of deindividuation.

Partly to overcome these obstacles, the focus of deindividuation theory moved away from anonymity during the 1980s. Most studies from that period induced deindividuation by getting participants to focus attention outward in other ways. But despite more and more extreme (and increasingly contrived) experimental designs, many studies simply failed to support deindividuation theory or reported contrary results. A metaanalysis (combining all experimental results in one overarching analysis) of deindividuation studies conducted in 1998 concluded that large groups and crowded anonymous settings do not increase disinhibition and antinormative behavior. Even the reduction of self-awareness in more direct and invasive ways does not yield consistent evidence of disinhibition. Four decades of research failed to confirm the theory.

Reconceptualizing Deindividuation

To explain the failure of deindividuation theory, researchers revisited its starting assumptions about crowds. These were largely based on Le Bon, but he, as noted, was strongly biased against crowds, seeing them as a left-wing threat to civilization. He claimed all collective behavior was irrational. But if Le Bon’s portrait of the crowd is wrong, then deindividuation theory set out to explain the wrong phenomenon.

Systematic research of crowds throughout history shows that Le Bon’s characterization of crowds was wrong. Although almost everyone is appalled by lynch mobs, Kristallnacht, and the Rwandan genocide, we should not let our horror and fears at the outcome cloud our analysis of the process. Violence in crowds is very rare and usually a last resort when other means of action are exhausted. But when it does occur, crowd historians have witnessed preciously little chaos and randomness. Most crowds behave orderly and restrained. Even when they loot and pillage and rape, crowds display a considerable amount of organization and structure to their atrocities. Far from blindly pursuing destruction, the crowd is normally propelled by moral beliefs and consensus. Moreover, its violence is not random but targeted and symbolic of its purposes (e.g., Islamist crowds would attack Western tanks or non-veiled women but not their own mosques). Of course there are cases in which the moral principles of the crowd are completely alien to ours, and their logic might be warped. But to advance understanding of crowd psychology, it is important to acknowledge that, to the members of the crowd, their actions make sense.

The implication for crowd psychology is profound: Collective behavior (however atrocious) can be under conscious control. Le Bon’s observation that crowd members are somehow automatically and inevitably mentally incapacitated and irresponsible is simply false. In some sense, this is a disturbing (if unsurprising) conclusion—it means that people are capable of committing the vilest atrocities willingly. But in another sense, it is constructive and positive: If crowd members make conscious decisions about how to act, then we can influence their behavior and hold them personally responsible if they violate the law. It also means that we can set out to provide a better explanation for collective behavior, namely, one that tries to understand how the actions of the crowd are socially regulated (rather than why they are chaotic).

Taking this new perspective, a large body of field research of crowds has noted that group norms inform collective action. Other field research has noted that crowd members act as a collective identity (which also comprises a set of norms). Yet more field research has documented that collective identities emerge and change in an intergroup dynamic (e.g., between demonstrators and police). It follows that the police can influence the crowd by changing its tactics. Insights from this research have had a major impact on public order policing in Europe, and these new strategies seem to pay off—”football hooliganism” has declined considerably in recent international matches.

These new insights have also been tested in experimental research of deindividuation effects. Results are broadly consistent with field studies of crowds and historical evidence. Thus, the settings which were originally thought to “deindividuate” participants were actually making them more responsive to situational norms. For example, making participants anonymous by dressing them in cloaks and hoods leads to greater aggression. But dressing them in nurses’ uniforms reduces it. Anonymity does not render people unthinkingly violent. Rather, anonymity increases their responsiveness to the normative cues present in their immediate environment.

Put together, experimental and field research suggest that crowd behavior is guided by a collective identity that emerges in the crowd. This common identity may become accentuated or polarized if an opposing group (such as the police) acts upon the crowd as if it were one, for example, by deploying indiscriminate tactics of crowd control. It is this collective identity which normatively regulates the actions of individuals in the crowd and which gives them a common goal.

In conclusion, social psychologists’ understanding of deindividuation has advanced enormously. Contemporary studies of collective action have moved away from the assumption that crowd members lose their identity. Instead, collective action is explained as the result of “normal” processes of social influence and intergroup relations. In this contemporary perspective, deindividuation is the transformation of a collection of distinct individuals into a group with a collective identity.


  1. Le Bon, G. (1995). The crowd: A study of the popular mind. London: Transaction. (Original work published 1895)
  2. Postmes, T., & Spears, R. (1998). Deindividuation and anti-normative behavior: A meta-analysis. Psychological Bulletin, 123, 238-259.
  3. Reicher, S., Spears, R., & Postmes, T. (1995). A social identity model of deindividuation phenomena. In W. Stroebe & M. Hewstone (Eds.), European Review of Social Psychology (Vol. 6, pp. 161-198). Chichester, UK: Wiley.
  4. Stott, C. J., & Adang, O. M. J. (2004). “Disorderly” conduct: Social psychology and the control of football hooliganism at “Euro-2004.” The Psychologist, 17,318-319.
  5. Zimbardo, P. G. (1969). The human choice: Individuation, reason, and order vs. deindividuation, impulse and chaos. In W. J. Arnold & D. Levine (Eds.), Nebraska Symposium on Motivation (Vol. 17, pp. 237-307). Lincoln: University of Nebraska Press.