1. What does the evolutionary approach have to do with explaining aggressive behaviour?

2. Evolution & Aggression survival reproductive potential The evolutionary approach explains aggression in terms of its ability to increase the chances of survival and reproductive potential of the individual. ‘adaptive response’ So we are looking at aggression as an ‘adaptive response’

3. Evolution & Aggression Lorenz (1966) – proposed a theory of aggression based on animal behaviour which he believed could be applied to humans. innate Aggression is innate and triggered by environmental stimuli. adaptive response Aggression is an adaptive response – it would have helped males eliminate rivals for mates and therefore lead to a genetic tendency to aggress towards other males Aggression against females wouldn’t have been so adaptive – males who are aggressive towards females are too dangerous to them and their children & they would be rejected as mates – making male on female aggression less likely.

4. Is Aggression Adaptive? Male sexual jealousy might be adaptive – something that developed for a purpose..what might this be? might aim to reduce female infidelity and deal with paternal uncertainty This type of jealousy can lead to Violence and aggression.

5. Is Aggressive Adaptive? Female emotional jealousy might be adaptive – something that developed for a purpose – might be aimed at the need to find a mate willing to invest resources in her and her children. Emotional infidelity may lead her partner to invest resources in another women and affect the children’s survival and her reproductive potential. This jealousy can lead to violence/ aggression.

6. Kinsey (1948) 50% of married men 26% of married women Admitted to what? Having sex with someone else whilst married

7. Cheating is adaptive quantityIt enables men to increase the quantity of offspring carrying his genes qualityFor women it may improve the quality of her offspring But! Knowing you’ve been cheated on…

8. Leads to.. Jealous rage

9. Buss et al (1992) Cross –cultural questionnaire study Hypothetical situation Multiple choice

10. Imagine you are in a long-term relationship. You discover that your partner has formed a deep emotional and a passionate sexual relationship with another person. Which aspect of your partner’s involvement would make you more jealous? A)The deep emotional relationship B)The passionate sexual relationship Both forms of infidelity distress each sex but men are more distressed about sexual whereas females are more distressed by emotional.

11. Results 51% men 22% women Reported sexual infidelity more distressing than emotional infidelity

12. Aggression in males For males another primary motivator is acquisition of status. In the EEA, good hunters accrued resources and skilled fighters could ward off rivals = ATTRACTIVE TO FEMALES. Sex for meat hypothesis?

13. High status males monopolise females Low status males at risk of not producing offspring L.S. males indulge in high risk strategies to compete for status Success enhances reproductive success

14. Male on Male Aggression Global homicide rates indicate that most victims and killers are male. (Buss & Shackleford 1997) 73% of male perpetrators in Detroit, USA are unmarried and 69% of victims are also unmarried. (Wilson & Daly 1985) In the same study 41% of them were also unemployed – the unemployment rate for the city as a whole was only 11% Suggesting competition for resources and mates may lead to social competition and homicide.

15. Daly & Wilson (1985) Investigated murders in Detroit in 1972 The motive behind most of the conflicts was status. Victims and offenders were unemployed and unmarried young men LOW STATUS AND WITHOUT A MATE So nothing to lose from fighting and potentially, everything to gain…

16. Male on Female Aggression However within relationships there is also evidence of high levels of aggression, usually if the male suspects infidelity.

17. Importance of Infidelity in Aggression Males can potentially be the victims of cuckoldry (raising a child not biologically his), whereas women cannot. It may therefore be adaptive for a male to be aggressive in order to prevent his partner being unfaithful. According to Daly & Wilson (1988) men have evolved strategies to deter female partners from committing adultery. At the extreme end uxorocide (wife killing) can be the unintended result of an evolutionary adaptation designed to control rather than kill a partner.

18. Until 1974 a man would not be punished for killing his wife’s lover ‘while in the act’. In 2002 a Thai court released a man after battering his wife to death with a golf club while in a jealous rage after she visited a former sweetheart. “Crime of Passion” “Temporary Insanity” Irresistible Impulse

19. Importance of Infidelity in Aggression Buss & Shackelford (1997) – men who suspected their wives might be unfaithful over the next year exacted greater punishment for known or suspected infidelity than men who did not anticipate future infidelity. Daly & Wilson (1988) – men who have been left or are just about to be left by their partner commit a high proportion of homicides of their partners, potentially because of the fear of losing them to another male.

20. Importance of Infidelity in Aggression Shackleford et al. (2000) – analysed half a million homicides, selecting 13,670 where a man had killed his wife. Younger women were much more likely to be killed by their partner regardless of the age of their partner. Although evolutionary theory would suggest a woman in her reproductive prime is least likely to be killed because she is ‘useful’, some argue that by killing his partner the male is preventing another male from benefiting from his loss – therefore not losing out twice.

21. Importance of Jealousy in Aggression There is also evidence to suggest that jealousy is experienced among both sexes in relation to infidelity. Evolutionary psychologists see this jealousy as an ultimately genetic behaviour. It is related to aggression because jealousy often leads to aggressive outbursts. Just being jealous won’t prevent infidelity but being aggressive as a result might.

22. Importance of Jealousy in Aggression So male sexual jealousy might be adaptive because it might aim to reduce female infidelity and deal with paternal uncertainty. Wilson et al. (1995) – gave women a questionnaire, those who agreed with items such as ‘he is jealous and doesn’t want you to talk with other men’ were twice as likely to experience serious violence from their partners. 72% of them needed medical attention after an assault from their partner. Dobash & Dobash ( 1984) studied female victims of domestic violence and found most women cited jealousy as the main cause.

23. Sexual Jealousy and Infidelity in Males MALE ON MALE AGGRESSION Daly & Wilson (1985) – 58 / 214 cases of murder motivated by sexual jealousy. Confidence in paternity and warning to potential rivals MALE ON CHILD AGGRESSION Link to parental investment Males reluctant to expend energy and resources in raising offspring of another male. MALE ON FEMALE AGGRESSION Designed to deter the female from indulging in behaviour not in the male’s interest. Miller (1980) – 55% battered wives cited jealousy as reason for husband’s behaviour. This was often unfounded, based only on suspicion and fear.

24. Importance of Jealousy in Aggression Female emotional jealousy might also be adaptive. It might be aimed at the need to find a mate willing to invest resources in her and her children. Emotional infidelity may lead her partner to invest resources in another women and affect the children’s survival and her reproduction potential. This jealousy can lead to violence/ aggression. Whereas male sexual infidelity, although potentially costly to a female, wouldn’t attract as much jealousy because she may risk pushing him away & losing resources.

25. Aggression in females For females, the costs of aggressive behaviour exceed the benefits. The mothers presence is more critical to the offsprings survival than the father’s. (Campbell 2002) High status, dominant, aggressive females not preferred as mates so no adaptive value in overt aggression. BUT low risk, indirect strategies such as gossiping, name calling and ostracising to decrease attractiveness of competing females developed to reduce risk of physical injury.

26. Importance of Jealousy in Aggression Harris (2003) – meta-analysis of 32 studies on sex differences in emotional response to imagined infidelity. Harris found men were more distressed by sexual infidelity, while women were more distressed by emotional infidelity – supporting the predictions of evolutionary theory. This research also supports Buss’ (1992) findings

27. Additional Evaluation? There are cultural differences in the murder rates of wives by husbands and the level of anxiety felt in response to sexual infidelity by males. This suggests that other factors must be influencing aggression and evolution cannot be the sole explanation. Buss & Shackelford (1997) argue that the theory cannot account for why infidelity is responded to differently by different men within the same culture. Some get drunk, others beat their wives, other kill the partner and others do nothing aggressive.

28. Additional Evaluation? Male and female differences in aggression are accounted for, as are differences in experiences of infidelity and jealousy, therefore they are not gender biased. However studies tend to focus on males as the perpetrators of the aggression. Some research has suggested that women are just as likely to physically assault their partner as men are. Some argue that evolutionary explanations justify male violence against females, by suggesting that it is natural and inevitable.

29. Young (1978) Asked students to describe their likely reactions to a jealousy inducing scenario Men – respond angrily, become drunk, threaten their rival. Women – cry, pretend not to care, try to increase own attractiveness to regain male attention.

30. Griskevicius et al (2009) gave students scenario of person of same sex spilling a drink on them at a party and not apologising. Majority of men would respond with direct aggression (eg, pushing the other man) Only a quarter of women would do so, most women most likely to walk away. Women most likely to use direct aggression when competing for resources that will aid their survival

31. Additional Evaluation? The basis of the explanation is genetic. It can therefore be seen as reductionist. The explanation is deterministic and ignores the role of free will in relation to infidelity and jealousy. The explanation is often supported by research using self-report measures. This creates issues of social desirability, particularly when investigating issues such as violence against women.

32. Past Question Jan 2013 Discuss evolutionary explanations of human aggression, including infidelity and/or jealousy. (24)

33. Past Question Jan 2013 AO1: Evolutionary explanations of human aggression focus on specific areas where aggression is thought to be adaptive. These include acquiring and protecting resources such as food, territory and mates, and status within the group, especially in males. High status then leads to greater access to resources in general and to mates in particular. AO1 detail for marks above Basic should include the evolutionary context, i.e. the need to ensure survival of one’s genes. There is a requirement for students to consider the relationship between human aggression and infidelity and/or jealousy. This can make up the entire answer or alternatively form part of a more general essay on explanations of human aggression. Aggression in relation to infidelity and/or jealousy is usually linked to male mate-retention strategies in response to imagined or actual sexual infidelity. There are a range of mate-retention strategies several of which do not involve aggression of any sort. For credit to be earned students must retain a clear focus on human aggression Again the evolutionary context would be necessary for marks above Basic; this could include reference to potential cuckoldry and the evolutionary drive for men to invest resources only in their own offspring. Outlines of non-aggressive strategies (e.g. surveillance) might earn AO2/AO3 credit if used as relevant commentary on aggression in relation to infidelity/jealousy.