1. Aggression
“An act carried out with the intention to harm another person”
Instrumental aggression – a means to an end
Hostile aggression – an end in itself

2. Aggression What causes people to behave aggressively?
Social learning
Deindividuation
How does our environment affect the likelihood of aggressive behaviour?
Heat, noise, crowding

3. Social Learning Theory (SLT)
Environment
Observation
Model
Imitation
Observed consequences
Vicarious reinforcement and punishment

4. Social Learning Theory
Bandura (1965)
Observational learning of aggression
Mead (1965)
Cultural transmission of aggression
Patterson et al (1989)
Learning of aggression within family

5. Deindividuation
Normal constraints on behaviour are weakened when a person loses their sense of individuality
Crowds, uniforms, drugs & alcohol
Less likely to be identified & held responsible for aggressive behaviour
Anonymitydeindividuationaggression

6. Deindividuation

7. Deindividuation

8. Deindividuation

9. Deindividuation Zimbardo (1969) Zimbardo (1973; Stanford Experiment)
Hooded PPs were more aggressive
Zimbardo (1973; Stanford Experiment)
Guards’ aggression increased by uniforms, sunglasses, night-time
Mullen (1985)
Violence of mob lynching a function of crowd size

10. Environmental Stressors
Heat
Noise
Crowding

11. Environmental Stressors
Stress  Arousal  Aggression
As arousal increases it becomes easier to trigger an aggressive response (up to a point)

12. Environmental Stressors
Aggressive responses most likely at moderately high levels of stress
Likelihood of aggressive behaviour
Level of stress