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  • Created by: Laura
  • Created on: 07-06-13 09:39


Deindividuation refers to a psychological state in which individuals have lowered levels of self-evaluation (e.g. when they are in a crowd or under the influence of alcohol) and decreased concerns about the evaluation by others. People are more likely to be aggressive if they have a loss of individuality, which leads to reduced self restraint, leading to impulsive behaviour.

There are three main factors that contribute to Deindividuation:  Crowds or large crowds,  Anonymity – wearing a uniform or a mask,  Altered Consciousness – drunk or drugged state

Zimbardo believed that individual behaviour was rational and complied with societal norms. Whereas, Deindividuation behaviour was based on primitive urges and therefore did not comply with societal norms.

It is said that the larger the crowd, the more anonymous/ less responsible a person will feel so they are more likely to go against social norms, such as aggression. This is because there is less fear of getting caught and a reduced sense of guilt. 

Underlying assumption;

Being in a crowd = Deindividuation = Aggressive 

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Research support

Zimbardo - divided undergraduates into two groups, on group was in a deindividuated condition (lab coats and hoods) and the other was not deindividuated. (Wearing normal clothing and a name tag) Those in the deindividuated state shocked the learner for twice as long as the ppts in the individuated state.

However it was only conducted on students, reducing EV

Diener – conducted a naturalistic observation of 1,300 trick or treating children in the US. Diener noted that children in large groups wearing costumes were more likely to perform antisocial actions such as stealing sweets or money as they could not be identified as easily.

Low EV – only American children so cant generalise findings to other cultures or other age groups. Also there are ethical probs with the naturalistic observation

Silke – Analysed 500 violent attacks occurring in Northern Ireland. 206 of these attacks were carried out by people who wore some form of disguise so that there identity was not known. Furthermore, the severity of the violent attacks was linked to whether the perpetrator was masked or not.

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Contradictory evidence

Nurses VS Klu Klux Klan – Johnson and Downing found that normative cues are important. It is not to do with Deindividuation but about the uniform that they were wearing and what they thought of it

Meta Analysis – this produced mixed results and said that there was not enough good research support to say that putting someone in a crowd or wearing a uniform will lead to aggression and was not enough to say that.


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Cultural and Gender differences – In large crowds, it is more likely to be aggressive if it is just males. This could possible be due to their testosterone levels and the idea of competition – fight or flight. Whereas females are more likely to tend or befriend.

Reductionist – this says that it is way to simplistic to say that Deindividuation will lead to aggression. It needs other cues to make a difference.

Free Will VS Determinism – This is saying that aggression should be expected from a crowd, but it doesn’t think about people’s control.


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