Deindividuation is a psychological state in which people lose their sense of individual identity and personal responsibility while immersed in a group, crowd, or anonymity.
Normal checks on behavior, such as guilt and fear of judgment, weaken, so conduct follows the group’s norms. It explains why people often act more recklessly in a crowd than alone.
Key Takeaways
- Definition: Deindividuation is a state in which you become so immersed in the norms of the group that you lose your sense of identity and personal responsibility. An individual relinquishes individual responsibility for actions and sees behavior as a consequence of group norms and expectations.
- Le Bon: Le Bon was the first to recognize how individuals’ behavior changed in a crowd.
- Anonymity: Anonymity leads to loss of internal restraints, self-identity, and responsibility for our behavior. Conditions that increase anonymity serve to minimize concerns about evaluation by others and weaken normal controls based on guilt, shame, or fear.
- Diffusion of Responsibility: Diffusion of responsibility leads to less feelings of personal guilt when committing aggressive acts.
- Self-Awareness: Prentice-Dunn et al. (1982) suggested it was a reduced self-awareness rather than simply anonymity that leads to de-individuation. They proposed two types of self-awareness: public and private.
Definition and Historical Background
Deindividuation is a process where people lose their sense of socialized individual identity and resort to unsocialized and anti-social behavior.
Deindividuation is a state of decreased self-evaluation in a crowd and is one of the most widely cited effects of social groups (Postmes and Spears, 1998).
Deindividuation is characterized by a lower awareness of the self and one’s individuality. This may result in anti-normative and disinhibited behavior, “what forces crowd members at times to behave in uncivilized and violent ways (Diener, 1976).
Classical Theories
Gustave Le Bon’s crowd theory provides the basis for deindividuation (Postmes, 2001). In The Crowd, Le Bon proposes that anonymity, suggestibility, and contagion can turn groups of people into so-called “psychological crowds.”
The collective mind of the crowd takes over the individual’s. Individual members become “irrational, fickle, and suggestible” (Postmes, 2001) and, as a result, become controlled by the crowd’s leader, capable of anti-normative acts.
Le Bon’s theory of The Crowd came to influence many theories of collective behavior, such as those of Freud, McDougall, Blumer, and Allport.
The 1950s brought a resurgence in popularity for Le Bon’s idea.
Festinger et al. (1952) formalized Le Bon’s crowd theory.
Individuals are not “seen or paid attention to as individuals,” and “under conditions where the member is not individuated in the group, there is likely to occur of the member a reduction of inner restraints against doing various things.”
Early theorists, such as Festinger (1952), believed deindividuation occurred when a group did not treat members as individuals. Individuals felt unaccountable.
This unaccountability leads to a reduction in inner restraint, increasing behavior that would normally be inhibited. Like Le Bon, Festinger defined deindividuation as a loss of individuality through submergence in a crowd. The mind stayed intact.
However, to Festinger, this individuality is not replaced by the collective mind. Rather, deindividuation simply releases an individual from their normal moral restraints (Postmes and Spears, 1998).
Philip Zimbardo’s Approach to Deindividuation
Zimbardo did not see deindividuation as solely a group phenomenon, applying deindividualization as broadly as suicide, murder, and hostility in relationships (Postmes and Spears, 1998).
Although he studied anti-social behavior, Zimbardo stressed that deindividuated acts could be prosocial.
Minimal self-observation and concern for social evaluation, he argued, weaken controls based on guilt, shame, fear, and commitment (Zimbardo, 1969).
Several conditions can trigger this: anonymity, diffused responsibility, an overloading environment, unfamiliar situations, and drugs or alcohol.
The result is often impulsive, over-the-top behavior.
Zimbardo’s 1969 Shock Study
Aim: Zimbardo tested whether hiding a person’s identity would increase their willingness to hurt someone else.
He also tested reactions to victim information.
Method: Female volunteers, told they were in a study of “creativity under stress,” shocked another student whenever a light signaled a wrong answer.
Deindividuated participants wore hooded coats hiding their faces and were addressed only in groups.
Individuated participants wore their own clothes and large name badges. The measure was shock duration.
Results: Hooded participants delivered roughly twice as much shock as individuated ones.
Their shock durations rose across the trials rather than tapering off.
Told the “victim” was warm and likeable, individuated participants eased off. Deindividuated participants did not adjust at all.
Conclusion: Anonymity releases aggression.
It also disconnects that aggression from moral judgment of the victim, since hiding identity strips away cues that would normally restrain cruelty.
A similar design featured in Zimbardo’s later Stanford Prison Experiment, where guards wore uniforms and mirrored sunglasses.
A separate replication using Belgian soldiers found the opposite pattern.
Hooded soldiers grew self-conscious and anxious rather than aggressive, while uniformed soldiers kept their usual baseline anonymity (Postmes, 1998).
Diener’s Field Studies: The Halloween Effect
Edward Diener argued that earlier studies found inconsistent support for deindividuation because they ignored the individual psychological changes involved (Diener, 1980).
One early test, Diener, Westford, Dineen, and Fraser (1973), had participants hit a non-responsive “pacifist” actor.
Results were inconsistent. Isolated individuals sometimes showed more aggression than groups did (Postmes and Spears, 1998).
Diener, Fraser, Beaman, and Kelem (1976) moved the test outdoors. They used an everyday ritual, not a lab task.
Aim: They tested whether anonymity and group membership increase spontaneous stealing among ordinary trick-or-treaters.
Method: Homeowners put out bowls of sweets marked “take one” on Halloween night.
Some asked each child’s name first (non-anonymous); others said they could not tell who the child was (anonymous).
Over 700 children were observed. The measure was whether a child took more than one sweet.
Results: Stealing rates varied sharply by condition.
| Condition | % Who Stole Extra |
|---|---|
| Anonymous and in a group | 57% |
| Anonymous and alone | 21% |
| Non-anonymous and in a group | 21% |
| Non-anonymous and alone | 8% |
Conclusion: Anonymity and group membership each raised stealing on their own.
Children who were both unidentifiable and grouped stole at nearly seven times the rate of identifiable children acting alone.
However, the field setting made self-awareness itself almost impossible to measure directly. Later theorists tried to close that gap.
Prentice-Dunn and Rogers (1982) picked up the gap directly.
Participants played a video game they believed could shock an opponent.
One group sat in a dim, loud room and was encouraged to talk, drawing attention outward.
Another played a calmer game in a quiet, well-lit room.
The dim, loud group showed higher aggression, consistent with reduced private self-awareness (Postmes, 2001), a distinction explored fully next.
Criticism and Reconceptualization
Historically, evaluating the research relating to deindividuation has been difficult, as the definition of deindividuation has evolved rapidly. Researchers have seen deindividuation theory as neglecting how crowd behavior may be the product of local group norms.
As late as the 1970s, deindividuation was a focus of psychological research, but there remained little empirical support for deindividuation theory. The theory needed revision.
The evidence supporting deindividuation driven by anonymity was inconsistent, and there remained no evidence for the state of deindividuation itself (Diener, 1980).
As a result, the next decade saw a reconceptualization of deindividuation theory. The main contributing factor in anti-normative behavior in deindividuated groups shifted from a lack of accountability among group members to the anonymity that belonging to the group brings. Anonymity now took priority.
According to Le Bon, collective behavior is always irrational, and individuals in the crowd lose their intellectual control.
However, sociologists beyond Le Bon found that crowds can actually encourage norms for restraint and orderly behavior (Turner and Killian, 1972).
Theorists postulated that group behavior was a consequence of local group norms rather than the anonymization of individuals within groups. Empirical tests soon followed.
Johnson and Downing (1979) tested this hypothesis by recreating Zimbardo’s original experiment and dressing participants in uniforms similar to that of the Ku Klux Klan or nurses.
Those dressed as Ku Klux Klan members shocked actors more, and those dressed as nurses shocked actors less than the control group. Thus, this research supports the idea that those in groups are sensitive to and highly influenced by normative cues.
Prentice-Dunn et al. (1982) suggested it was a reduced self awareness rather than simply anonymity that leads to de-individuation. They proposed two types of self-awareness.
Public self-awareness
The individual’s concern about the impression presented to other people, knowing that they will be evaluated. This is reduced by being in a crowd, diffusion of responsibility, anonymity, and role models within the group, which set the social norms. The audience effectively disappears.
Loss of public awareness leads to loss of public standards of behavior or a lowering of inhibitions. If an individual is self-focused, they act according to their own values, so aggressive behavior is less likely.
Private self-awareness
Concern individuals have for their own thoughts and feelings. This is reduced by becoming so involved with group activities that individuals “forget” themselves.
Loss of private awareness leads to a loss of internal standards and an over-reliance on environmental cues. If a person is focused on the group, private self-awareness decreases further. The internal brakes loosen, so aggressive behavior becomes more likely.
Postmes and Spears’ 1998 review, Deindividuation and Antinormative Behavior, a meta-analysis, showed little support for the occurrence of deindividuated, antinormative behavior or the existence of a deindividuated state.
However, the analysis showed something else: groups and individuals conformed more closely to norms specific to their situation while “deindividuated.” That distinction mattered.
Prentice-Dunn and Rogers (1982) built on this by extending the theory into what they called “differential self-awareness theory.” It names two cue types that disinhibit behavior.
“Accountability cues,” such as anonymity and diffusion of responsibility, decrease public self-awareness, so crowd members worry less about being evaluated and do not expect negative consequences for their behavior.
Conversely, “attentional cues,” such as group cohesiveness and physiological arousal, draw attention away from oneself, reducing self-regulation and attention to personal standards of behavior.
Both cue types can produce antinormative, disinhibited behavior, but Prentice-Dunn and Rogers (1982) held that only reduced private self-awareness leads to genuinely deindividuated behavior.
Social Identity Theory’s Explanation of Deindividuation
The definition of deindividuation shifted markedly over time.
Early theorists such as Festinger et al. (1952) linked it to not being scrutinized or held accountable in a group.
Zimbardo (1969) later defined the inputs and effects of deindividuation more fully.
He expanded the causes from sole anonymity to contextual factors such as reduced responsibility, arousal, sensory overload, unpredictability, and drugs or alcohol.
Zimbardo (1969) extended Festinger’s theory of deindividuation to create a theoretical framework specifying the variables leading to deindividuation and output behavior.
Zimbardo characterized the resulting behavior as emotional, impulsive, irrational, and “in violation of established norms of appropriateness.”
Diener went further still, arguing that reduced self-awareness, not mere anonymity, was deindividuation’s defining feature.
Prentice-Dunn and Rogers (1982) traced disinhibition specifically to a loss of conscious accountability.
The Social Identity Model (SIDE)
Social identity theorists argue that deindividuation does not cause a loss of self.
Instead, it shifts identity from an individual to a member of a crowd.
For example, the shared identity of a group of protestors can unite demonstrators who otherwise disagree strongly. The shift is not random.
Conversely, the whole group may revolt if another group, such as the police, treats it as one undifferentiated mass (Reicher et al., 1995).
The most influential version of this view is the social identity model of deindividuation effects, or SIDE. SIDE names this pattern.
SIDE argues that anonymity, group cohesiveness, and immersion reinforce group salience and conformity to group norms rather than erasing identity altogether (Postmes and Spears, 1998).
It predicts conformity to the norms of the specific group involved, not to general standards of conduct.
The SIDE model can explain the outcomes of several deindividuation experiments.
SIDE Applied: Reinterpreting Classic Findings
SIDE can reframe earlier findings in identity terms.
Playing video games in a dark room with loud rock music, for example, produced more aggressive behavior. This may reflect participants believing aggression was expected and consistent with their group identity in that situation (Postmes and Spears, 1998).
Placing participants in front of a mirror, by contrast, focuses attention on individual identity rather than the group (Froming, Walker, and Lopyan, 1982; Postmes and Spears, 1998). Context shapes the outcome.
Awareness of one’s own individuality can also change how a person reads the group’s norms.
In Froming et al. (1982), the study where participants shocked actors, those low in private self-awareness shocked more when they believed others favored shocking more. They shocked less when they believed others favored shocking less.
Examples
Deindividuation, at its extremes, is responsible for the collective behavior of violent crowds, such as lynch mobs, as well as mass social phenomena, such as genocide, stereotyping, and disinhibited behavior online.
Collective Responses to Health Crises
Lewis, Himmelberger, and Elmore (2020) examined the effects of self-reflection on pro-social behavior, citing the COVID-19 pandemic as a possible application.
Wearing surgical masks, according to Mullen et al. (2003), decreases self-awareness and increases the likelihood of selfish behavior (Miller and Rowold, 1979), and the increasing anonymized interactions of those during the pandemic may have led to deindividuation.
Genocide
Researchers such as Staub (1989) believe deindividuation is a necessary factor in genocide. Hitler and Mussolini both drew on Le Bon’s crowd theory when building their programs of mass internment and murder (Postmes and Spears, 1998).
Encouraging deindividuation among group members reduces self-awareness and personal responsibility.
Authoritarian governments often build organizations and military units designed to enhance deindividuation. Uniforms and strict rules of conduct help individuals commit violence by reinforcing conformity and diffusing responsibility (Woolf and Hulsizer, 2007).
The SS took this further.
Hitler’s youth and the Khmer Rouge relied on deindividuation the same way. Members were expected to endure danger and submit to authority, fighting and killing from the start.
This bred unquestioning loyalty.
Shared training, experience, and privilege built strong group ties, and ordinary rules did not legally apply to SS members. As a result, deindividuation fed collective actions that broke down the moral prohibitions against mass murder (Staub, 1989).
The Internet
Deindividuation research has also examined anti-normative behavior in computer-mediated communication, such as the internet.
Lee (2007) studied how deindividuation affects group polarization during online communication. Participants either shared personal information (individuated) or stayed completely anonymous (deindividuated) before discussing several social problems.
Deindividuated participants identified more strongly with their partner. They also defended their arguments more strongly than participants in “public” conditions, consistent with the SIDE model. A newer study went further.
Aim: Zimmerman and Ybarra (2016) tested whether online anonymity increases aggression, and whether exposure to another person’s aggressive or supportive behavior changes that effect.
Method: Participants completed a team word-unscrambling game through blog-style posts, either anonymously or with their identity visible.
All were also exposed to a scripted “model” participant who reacted to a team setback either aggressively or supportively.
Results: Anonymous participants behaved and posted more aggressively overall. Exposure to an aggressive model made this worse: anonymous participants who saw aggression modeled responded far more aggressively than anonymous participants who did not.
Conclusion: Online anonymity increases aggression, but not uniformly. It makes people more responsive to the visible norms around them, matching the SIDE model’s prediction of conformity to locally salient norms.
Deindividuation online is also linked to other rule-breaking. Hinduja (2008) found that people who prefer anonymity and pseudonymity online were more likely to pirate software than others.
Reducing Deindividualization
Those with greater levels of self-awareness show lower rates of anti-normative behavior because of deindividuation. This self-awareness has often been simulated by mirrors (Postmes and Spears 1998).
For example, students who take tests in front of mirrors cheat at lower rates than those who do not (Diener and Wallbom, 1976).
References
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