1. Page 1 Evolution and human aggression

2. Evolutionary explanations of human aggression Aggression is adaptive Discuss reasons for this statement Survival Increase chances of procreation

3. Page 3 The evolutionary approach to explaining aggression sees aggression in terms of its ability to increase survival chances therefore to enhance reproductive success. How can aggression improve survival chances?

4. Page 4 Aggressive behaviour has evolved to serve adaptive problems of social living Gain territory and resources i.e. children bullying others for money or toys, adults mugging and warfare. Defending against attacks: aggression to prevent loss of resources and status necessary for reproductive fitness i.e. “stick up for yourself.

5. Page 5 Inflicting cost on same sex-rivals: aggression between same sex members to aid in the competition for resources and mates i.e. men fighting over women. Negotiating status and power hierarchies: aggression to gain prestige and dominance among same-sex members i.e. gang violence to “prove oneself” to aid sexual selection by opposite sex members i.e. women attracted to dominant and powerful men.

6. Page 6 Deterring rivals from future aggression: aggression to maintain dominance and fear in others i.e. making threatening gestures, reinforcing aggressive reputation, maintaining an aggressive appearance Deterring mates from infidelity: aggression against opposite-sex members to maintain fidelity of desired long-term mates and ensuring paternity i.e. wife-battering

7. Page 7 Task Why is aggressive behaviour an adaptive advantage? (4)

8. Page 8 Why do men and women express aggression differently? Need to compete with other males for access to choosy females Lower status men are willing to take greater risks by using aggression or face genetic extinction. Human males cannot risk wasting investment on offspring who are not their own so they should show more jealous violent aggression relating to female fidelity- both towards the male competitors and their long-term female mates if infidelity is suspected especially if the female is young and reproductively valuable If the female commits sexual infidelity the man faces paternity uncertainly What about reconstituted families, adoption and fostering?

9. Page 9 Human females can always guarantee that their offspring are their own and compete with other females for the quality of men rather than for the availability. Women take fewer risk with violence and use more indirect form of aggression. If a male is unfaithful the female partner risks losing his time, resources, energy, protection and commitment to her children. 40% of domestic violence victims are men in 2009 according to the British Crime Survey.

10. Page 10 Research evidence Male-male aggression Cross-culturally, human violent aggression and homicide is far more common in males, against other males (Daly and Wilson, 1988). Homicide is more common in poor and unmarried men than richer, married ones (Wilson and Daly, 1985). Sexual jealousy produces more male- male homicides than female-female. Female-female aggression Female aggression is more verbal against other women to maintain status and reduce the attractiveness of competitors, especially by using verbal criticism of the physical unattractiveness of other females and their promiscuity (for men looking for long-term mates with sexual fidelity) to lower their appeal in the eyes of men (Buss and Dedden, 1990).

11. Page 11 INTER-SEXUAL JEALOUSY AGGRESSION Most male non-sexual aggression against women involves girlfriends and spouses due to sexual jealousy. In a study of 36 Baltimore spousal homicides, 25 were attributed to jealousy, and the wives were the victims in 24 of these cases (Guttmacher, 1955). In a study of battered women, 57 out of 60 attributed the violence to their husband's extreme jealousy and possessiveness (Hilberman and Munson, 1978). In 100 cases of spousal violence, the husbands' frustration over their inability to control their wives and accusations of infidelity were the most reported causal factors (Whitehurst, 1971). Young wives/girlfriends are more likely to be killed than older ones (Daly and Wilson, 1988). Verbal aggression and non-lethal physical violence against mates is often similar in men and women, but spousal homicide by women is less frequent and often due to defense against a jealous abusive husband (Daly and Wilson, 1988).

12. Page 12 Task HOW does the role of evolution and natural selection explain aggression? (6) Explain sex differences in aggressive behaviour Explain why beating your wife is an adaptive behaviour

13. Page 13 Evaluation In your pairs can you come up with a strength and a weakness of using evolution to explain aggression?

14. Page 14 Evaluation Cultural differences in murder rates of wives by husbands and in the degree of anxiety felt in response to sexual infidelity by males suggest that factors other than those determined by evolution play a part. Most relationships where a partner is or has been unfaithful continue or end without physical violence.

15. Page 15 Some critics feel that evolutionary explanations justify violence by men against women as natural and inevitable. on average, two women a week in England and Wales are killed by a violent partner or ex-partner. Killing a partner because of infidelity “crime passionel” is no longer accepted as a defense in court (since 2008)

16. Page 16 The evolutionary perspective offers an explanation of how aggressive behaviour due to suspicions of infidelity may arise as a result of natural selection. Evolutionary explanations account for male and female differences in their experiences of infidelity and jealousy as due to different selective pressures, and therefore are not gender biased. Evolutionary theory brings explanations of infidelity and jealousy down to the level of genes and therefore can be perceived as being reductionist. It is also determinist, as it disregards any role for free will in behaviour relating to infidelity and jealousy. Cultural differences