1. Social Psychological Explanations of Aggression RT Riot film

2. Deindividuation Theory of Aggression

3. Deindividuation – to lose one’s sense of individuality and identity. Can occur in 2 main ways – – Becoming part of a crowd – Identifying with a particular role ( often aided by wearing uniform or mask) Can be used to explain aggression which occurs when in a group.

4. Le Bon (1896) – individuals are more likely to behave in aggressive manner when part of a large anonymous group. A collective mindset is created and the group can become a ‘mob’. Individuals feel less identifiable in a group, so the normal constraints that prevent aggressive behaviour may be lost. The shared responsibility for action reduces individual guilt.

5. Diener (1980) Deindividuation occurs when self awareness is blocked by environmental events. Critical factors include : – Strong feelings of group membership – Increased levels of arousal – Focus on external events – Feeling of anonymity The deindividuated individual is trapped in the moment, perception of time is distorted and they are unable to consider consequences.

6. Diener cont. Increased arousal External focus Strong group feelings Sense of anonymity Reduced self awareness DEINDIVIDUATION

7. Prentice-Dunn & Rogers (1982) Modified Diener’s theory to distinguish between: – Public self awareness - concern over the impression of yourself you are presenting to others when you are aware of being judged. – Private self awareness – your sense of self, consisting of thoughts, feelings, values and internal standards of behaviour. Reduction in either can result in aggressive behaviour, but only reductions in private self awareness can lead to genuine deindividuation.

8. Key Study Zimbardo ( 1971) Zimbardo Prison Experiment

9. Zimbardo (1969) Explored deindividuation in female undergraduates. Group 1 dressed in white lab coats with hoods over their faces Group 2 wore large name tags. All pps observed a woman being interviewed and evaluated her performance by administering electric shocks. Condition 1 – pleasant interviewee, condition 2 – obnoxious Group 2 shocked the obnoxious interviewee more than the pleasant one Group 1 (deindividuated) shocked both interviewees equally. Zimbardo concluded that deindividuation increased aggression, making it indiscriminate and not at all influenced by individual characteristics. Is it relevant that all the participants were women?

10. Ellison et al (2005) Field experiment – drivers of convertibles with tops up beeped more than those with tops down ( roof down). Driving simulation exp’t with 289 psych student pps. Measured aggressive driving (speed, jumping red lights, collisions etc.) in tops up / tops down conditions. More aggression shown in tops up (anonymous) condition. Is this experiment high or low in ecological validity? Why?

11. Rehm et al (1987) Aggression in handball Deindividuation was created by giving one team orange shirts, whilst other team wore own clothes. In boy teams, uniformed teams were more aggressive than non-uniform. In girl teams, no differences found. Researchers concluded that uniform > loss of individuality > deindividuation. Is there an alternative explanation? How can the gender difference be explained?

12. Cross cultural evidence Watson (1973) – 24 cultures. Warriors in face and body paint more likely to kill, mutilate and torture captured prisoners. Silke (2003) – violent assaults in Northern Ireland. 206 / 500 cases carried out by offenders wearing masks or disguises. Anonymous attackers were more prolific and inflicted more serious physical injuries than identifiable attackers.

13. http://www.ted.com/talks/lang/eng/philip_zi mbardo_on_the_psychology_of_evil.html http://www.ted.com/talks/lang/eng/philip_zi mbardo_on_the_psychology_of_evil.html