1. Aggression Social psychological explanations Biological explanations
Evolutionary explanations

2. Social psychological explanations of aggression
Social learning theory
Deindividuation
Institutional aggression

3. Social learning theory
All humans have the biological potential for aggression but the expression of aggression is learnt
We learn aggression by observation and imitation of the behaviours of others
Bandura et al. – children imitated behaviours of an aggressive model on a bobo doll

4. Social learning theory
Children observe consequences of behaviours via vicarious reinforcement (Bandura & Walters)
Teaches child about appropriate and effective social conduct
Children form mental representations of social events
These influence expectancies of future outcomes – if expectation of reward is bigger than punishment, children display the behaviour

5. Social learning theory
Production of behaviours is influenced by…
Direct experience – rewards for aggression attach value to it
Self-efficacy – successful use of aggression gives children more confidence that it is effective

6. Evaluation Does punishment prevent imitation or learning itself?
Bandura – children rewarded for aggression, and all 3 groups showed similar levels of aggression, suggesting learning is independent of reinforcements but production of behaviours is not
Is social learning evident in adults?
Phillips – homicide rates in the US increase after boxing matches

7. Evaluation
The concept of vicarious learning is necessary to explain findings when direct reinforcement is inevident
This theory can explain individual differences in aggression
Different individuals learn differently in different cultures (‘culture of violence’ theory)
Different situations have different aggressive requirements (context-dependent learning)

8. IDA Is social learning theory valid?
Results may have been due to demand characteristics
Results may not be generalisable to real people
Ethical issues (protection from harm) make it difficult to scientifically test social learning theory

9. Deindividuation
A process whereby people lose their sense of socialised individual identity and engage in unsocialised, often antisocial, behaviour
2 things prohibit antisocial behaviour:
Identifiability (so anonymity enables it)
Social norms (so collective mind enables it)
Groups reduce these constraints, making aggression more likely

10. Deindividuation
Milgram – separation from victim makes it easier to shock them, outlining the role of anonymity
Zimbardo – faceless crowds diminish awareness of individuality so there is less fear of retribution and diminished sense of guilt
Anonymity decreases public self-awareness so larger crowds mean greater anonymity meaning more aggression

11. Evaluation
The Stanford Prison Experiment – relative anonymity of guards decreased self-awareness, so brutally treated prisoners. This is because they were deindividuated
Anonymity – does it matter whether the aggressor or aggressed is anonymous? Does it matter if the out-group or in-group cannot identify you?

12. Evaluation
Watson – 23 different cultures changed appearance in battle; the more dramatic the change, the more savage the soldier
Postmes & Spears meta-analysis – antisocial behaviour not more common in large groups
Spivey & Prentice-Dunn – deindividuation is situational so prosocial cues lead to prosocial behaviours (e.g. religious gatherings, concerts)

13. IDA
Application – Mann – crowds form that urge suicide jumpers to jump, and this is most common when the jumper is high, it is dark and the crowd is large (i.e. more deindividuated)
Gender bias
Cannavale et al. – men more deidividuated
Diener et al. – men more disinhibited

14. Institutional aggression
Within groups: Prisons
- The importation model
Aggressive social histories are imported into prisons and influence adaptation to prison environment
Pre-prison gang membership is a key determinant of prison violence (Huff – gang members are 10x likely to murder, 3x likely to assault)

15. Institutional aggression
Within groups: Prisons
The deprivation model
Oppressive prison conditions (e.g. overcrowding, lack of staff experience) cause aggression
Davies & Burgess – experienced guards are less likely to suffer assault
Sykes – loss of liberty, autonomy and security increase anxiety that causes violent rebellion

16. Evaluation
Harer & Steffensmeier – black inmates are less associated with drug/alcohol-related crimes than white inmates, reflecting US society and supporting the importation model
DeLisi et al. – gang membership is not correlated with prison violence. This could be due to isolation of pre-prison gang members – Fischer – isolating gang members reduces violent assault by 50%

17. Evaluation
McCorkle et al. – lack of privacy, meaningful activity and overcrowding influence peer aggression
Importation model may explain prisoner/prisoner aggression and the deprivation model explains prisoner/staff aggression

18. IDA
Application – Wilson at HM Woodhill lowered temperature, increased space, gave an outside view and played radio in prison. Prison violence was eradicated, but the prison shut down due to political pressure (the worst people can’t have the best things)

19. Institutional aggression
Between groups: genocide
Staub’s stages of genocide
Difficult social conditions
Scapegoat of a target group
Dehumanisation of that group
Killing begins
Passivity of bystanders allows killing to continue

20. Evaluation
Intervention by outside agencies may shorten genocide, but cause the aggressors to intensify their efforts. In the Rwandan genocide, the death toll rose to 8,000 per day. But, doing nothing signifies apathy/consent to the killing

21. IDA
Application – dehumanisation of outgroup members allows individuals high in social dominance orientation* to act more hostile towards refugees and asylum seekers
*Social dominance orientation = supporting social hierarchies and inter-group inequality

22. Biological explanations of aggression
Neural & hormonal mechanisms
Genetics

23. Neural mechanisms Low serotonin = high aggression
Mann et al. – serotonin inhibitors increased hostility & aggression in participants
High dopamine = aggression
Amphetamines increase dopamine and increase aggression
Antipsychotics lower dopamine and lower aggression

24. Evaluation
Bond – antidepressants increase serotonin and lower aggression
Raleigh et al. – monkeys fed diets high in tryptophan (chemical that increases serotonin) lowered aggression
Dogs selectively bred to be domicile (i.e. less aggressive) had increased levels of serotonin over generations
Couppis & Kennedy – dopamine levels increased after aggression in mice so may be a reward mechanism rather than a cause

25. Hormonal mechanisms High testosterone = high aggression
Increased levels of salivary testosterone evident in violent criminals
Increased levels of testosterone evident in violent drunks
The challenge hypothesis – testosterone rises to influence aggression in response to social challenges
Low cortisol = high testosterone = high aggression
Low levels of cortisol in habitual violent offenders and children

26. Evaluation
Albert et al. – some studies find no correlation between testosterone & aggression and those that have use self-report techniques so may not be valid
Mazur – testosterone influences dominance behaviours other than aggression in humans
McBurnett et al. – low cortisol levels in children with behavioural problems

27. IDA
Reductionism – complex human aggression cannot be completely explained by biological mechanisms
Application – the presence of weapons increases testosterone which may explain gun/knife crime
Gender bias – testosterone has been found to increase aggression greater in females than males, and high levels of testosterone were found in women of higher status but this has been ignored in research

28. Genetics
Twin studies
87%:72% MZ:DZ concordance (these are both high so genetics is not a likely factor)
Coccaro et al. – genetics accounts for 50% of the variance in aggression
Adoption studies
Humphreys & Mednick – the most aggressive adoptees have aggressive adoptive and biological parents (especially fathers)

29. Genetics
MAOA regulates the metabolism of serotonin, so low MAOA means unregulated serotonin metabolism so low serotonin, and this has been linked to aggression
There is a gene coding for MAOA so indirectly coding for aggression
Brunner et al. – violent dutch family members all had genetic MAOA deficiency
Caspi et al. – low MAOA + childhood maltreatment = aggression

30. Evaluation Genes are difficult to study:-
More than one gene may contribute to a behaviour
There are many environmental as well as genetic factors in aggression
Genes and environment may affect each other
Observational studies are more valid, and these have found less of a link between genetics and aggression

31. Evaluation Is aggression being measured?
Studies do not distinguish between violent and non-violent crime; habitual or non-habitual violence. Therefore, is aggression truly being measured?
Walter’s meta-analysis – genetics has a low influence on aggression, especially in more recent studies

32. IDA
Application – genetic studies could have serious consequences on people labelled as ‘genetically violent’ (e.g. chemical castration, genetic modification)
Determinism – do ‘violent’ genes make criminals less liable for their crimes?
Gender bias – if a gene is found, it may not have the same effect on both sexes

33. Evolutionary explanations of aggression
Infidelity & jealousy
Explanations of group displays (lynch mobs & religious groups)

34. Jealousy
Males have evolved to manifest aggression as sexual jealousy to prevent cuckoldry (investing resources in offspring other than their own)
Buss – aggressive mate retention strategies include direct guarding (restricting the partner’s autonomy) and negative inducements
Sexual jealousy may explain extreme violence:
Daly et al. – sexual jealousy is the most common motivation for killings in domestic disputes in the US
Dell – sexual jealousy is the cause of 17% of murders in the UK with males predominantly the perpetrators

35. Evaluation
Shackleford et al. – males who report using mate retention strategies are also more aggressive; femals who have been victim to mate retention strategies say their mates are more aggressive
Buss & Shackleford – males who anticipated infidelity (i.e. were sexually jealous) were more aggressive when it happened than those who did not expect it
Mate retention strategies may be used to look for signs of domestic abuse

36. Evaluation
Takahashi et al. – higher activation in amygdala and hypothalamus (parts of the brain associated with aggression) in males imagining scenes of infidelity
Edlund & Sagarin – research doesn’t tell us how the perceived locus of responsibility or degree of sexual act affects the aggressive response

37. Infidelity
Camilleri – sexual assault by a male partner directly linked to perceived risk of infidelity
Shields & Hanneke – victims of partner rape more likely to report engagement in extra-marital sex
Violence towards pregnant partners is an attempt to eliminate the offspring of a rival and free the partner to bear the male’s own offspring
Daly & Wilson – wife-killing is an unintended outcome of evolved strategies of extreme control

38. Evaluation
Camilleri & Quinsey – males convicted of partner rape more likely to have experienced cuckoldry risk
Burch & Gallup - pregnant women 2x more likely to be assaulted
½ a sample of pregnant women suffered blows to their abdomen (assumedly to terminate pregnancy)
Taillieu & Brownridge – women abused while pregnant were more likely to be carrying another man’s baby

39. IDA
Evolutionary approach cannot explain why different people have different reactions to sexual jealousy/infidelity – some abuse their partners, some kill their partners and some just drink
Gender bias – females also use mate retention strategies but this is ignored in research

40. Group displays: Lynch mobs
Groups of people that unlawfully kill others for some presumed offence
Blalock’s power-threat hypothesis states that lynch mobs form to prevent political power falling into the hands of the majority
This explains Tolnay & Beck’s findings of reasons for lynchings: “trying to vote” and “voting for the wrong party”
Lynch mobs evolved as a form of social control

41. Group displays: Lynch mobs
Hyatt – lynch mobs form due to dehumanisation of the target group
Hysterical desecration of bodies demean victims, leaving them unrecognisable
Lynchings are preceded by propaganda that reduce groups to animalistic stereotypes
Lynch mobs evolved to combat perceived threats

42. Evaluation
Clark – brazillian lynch mobs didn’t consider victims a threat to the majority politically or economically
Rothenberg – burning bodies very common in guatemalan lynchings, supporting dehumanisation
Rothenberg – lynchings not characterised by deindividuated conditions (lynch mobs are small and lynchings in broad daylight) so social psychological approach is inapplicable

43. Group displays: Religious groups
Some religious groups self-inflict violence that signals commitment to a group (Irons)
Committed group members are more likely to be cooperative
Cooperation leads to benefits e.g. food sharing & hunting
Religious groups have evolved to promote and maintain cooperation

44. Group displays: Religious groups
Self-inflicted violence deters selfish individuals
Zahavi – costly signalling rituals are ‘handicaps’ that deter free-riders but incur pain for in-group members
Religious groups have evolved to deter potential free-riders who may exploit the group

45. Evaluation
Ruffle & Sosis – religious males in Israeli Kibbutz are more cooperative than females because their rituals are more conspicuous
Sosis et al. – cultures in external warfare use more permanent displays of group membership

46. IDA
Social psychological approach may be necessary as Mullen found that, as lynch mobs grow, their killings are more savage
Application – solidarity within groups enables defence and competition between groups that explains religious conflict