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 www.psychlotron.org.uk

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

3. Social Learning Theory (SLT) • Environment • Observation • Model • Imitation • Observed consequences • Vicarious reinforcement and punishment www.psychlotron.org.uk

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 www.psychlotron.org.uk

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 www.psychlotron.org.uk

6. Deindividuation www.psychlotron.org.uk

7. Deindividuation www.psychlotron.org.uk

8. Deindividuation www.psychlotron.org.uk

9. Deindividuation • Zimbardo (1969) • 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 www.psychlotron.org.uk

10. Environmental Stressors • Heat • Noise • Crowding www.psychlotron.org.uk

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

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