EVOLUTIONARY EXPLANATIONS OF AGGRESSION Knowing the routes of aggression helps us understand it today. Animal aggression Craig – the aim of aggression is not to destroy the enemy but get rid of his presence. Lorenz argued that humans are animals and therefore show similar behaviour patterns. He argued aggression only occurred within not between species. The functions of aggression were; Only the fittest and strongest were selected by females – offspring more likely to survive Parents show aggression to protect their offspring so more likely to survive Help distribute a species in a balanced way as animals would have their own territories. Lorenz’s ideas have been criticised e.g as over-simplistic, and by suggesting parallels between human and non human animal behaviour. Fromm - human aggression compromises 2 forms A) Benign aggression –parent defends child B) Malignant aggression – gang warfare, ethnic cleansing. Nelson – states that Lorenz should have considered 3 basic factors that can affect aggression. Process of learning e.g. through observing others Structural causes – nature of social life – are there norms? Rules? Psychological causes – highlights failings of the biological approach. In the animal kingdom action is directed towards an ‘actual enemy’ in humans aggression may be motivated by other things e.g. mood (personal) heat (situational) Aggression in humans may well be adaptive but not usually ritualistic (like in animals). Use of weapons makes it more destructive. Explanations AO1 Reproductive success – aggression is the result of sexual competition. Females invest heavily in child rearing so very picky, males have to compete to be chosen and pass on genes. The image of man is ‘a provider of valuable resources’ i.e. they need to be more assertive and aggressive than women. Waller uses this theory to explain mass killings and genocide. We evolved to live in groups and need to define boundaries of behaviour for the group ‘in group – us’ and ‘out group – them’ this way of thinking is likely to lead to aggression. Xenophobia (fear of people from other culture/countries), the need to feel socially dominant and holding ethnocentric perspectives leads to acts of aggression and violence. AO2 Buss male to male aggression explains some but not all instances of aggression e.g. verbal aggression female to female to reduce ‘attractiveness of competitor in the eyes of males’. Giving an evolutionary advantage to the name caller. Infidelity and jealousy AO1 Daly and Wilson – men have evolved different strategies to deter women from committing adultery ranging from vigilance to violence. All fuelled by male jealousy – jealousy is an adaptation to deal with the threat of cuckoldry. Men are never certain they are the fathers, and cost is unwittingly investing resources in offspring not his own. The adaptive function of sexual jealousy is to deter mate from sexual infidelity. Support - Buss – strategies used, direct guarding e.g. chaperone, harems, and now coming home unexpectedly and negative inducements – threats In questionnaire women who said their husbands didn’t like them talking to other men were twice as likely to have experienced serious violence from partner – 72% needed hospital treatment. Studies of battered women have shown that in the majority of cases, women cite extreme jealousy on part of their partners as key cause (sexual jealousy primary cause of violence.) Uxorocide – (wife killing) may be unintended outcome of evolutionary adaptation that was designed to control rather than kill female partner. Support -Daly and Wilson – for women sexual jealousy is due to possible lack of resources/emotional support. Aggression in females. Females generally viewed as less aggressive since the cost of such behaviour outweighs the benefits More important for mother to survive as more critical to survival of offspring than father. A women has nothing to gain by exhibiting aggression since her aim is not to gain high status but to secure a valuable male. To this end females have evolved low risk and indirect strategies in disputes and conflicts e.g. gossip and ostracism, aimed at resucing the attractiveness of competing females Reseach – support Hill and Hurtado – among Ache of Paraguay, children are 5 times more likely to die if the mother dies, and 100% likely if this happens before child is aged 1. AO2 Research support – Shackleford – survey method of 461 men and 560 females in US all in committed heterosexual relationships. Males answered questions about their use of mate retention techniques and were assessed on how often they performed each of 26 different types of violent acts against partners. Females answered questions concerning partners use of male retention techniques and degree they used violence against them. From males found that negative inducements (sexual jealousy) were positively correlated with violence scores. Results from females confirmed this trend. Buss and Shackelford also found if men suspected wife might be unfaithful in following year exacted greater punishment for known or suspected infidelity than those who didn’t anticipate future infidelities. Application – Particular tactics of mate retention can be an early indicator of violence against female partner. Alerts you/friends/family to danger signs – help can be sought before violence. Buss in students in US – found males had higher stress levels when viewing pictures of sexual infidelity, females had higher levels when viewing pictures of emotional fidelity. Does the theory justify violence by men against women as natural and inevitable? Uxorocide Daly and Wilson conclusion that it is an unintended consequence was challenged by Shackelford – analysed ½ million homicides – selected 13 670 where a man had killed his wife – found younger women at greater risk (regardless of age of partner) Evolved homicide module theory – if women is young infidelity carries a double loss for male – loses a partner (decreased reproductive fitness) but another man gains and increases own fitness. By killing wife he prevents completion from gaining. Women can also behave violently towards their partners but this needs more research. Shackelford’s study was a survey using self report technique. Social desirability bias (as asking about violence against spouse) how likely are they to tell the truth. Evolutionary explanations do account for male and female differences in experiences of infidelity and jealousy. Evolutionary theories are reductionist and deterministic as disregards the role of free-will in behaviour Evolutionary approach/theories cannot be proved or disproved which means it lacks a scientific approach/rigour. Many of the theories can be explained in other ways and if the approach is flawed and the evidence is methodologically flawed the theory could be flawed. EVOLUTION OF HOMICIDE. AO1 Majority of killers and victims are men Acquisition of status Males are more motivated to acquire status since high status males have access to mates and resources for survival High status males are more likely to be selected by females since they will be better able to guarantee the survival of her and her offspring. Not engaging in conflict with other males can therefore be costly Low status males have to engage in high risk strategies to enhance their chances of reproduction Research – support Wilson –Daly – study in Detroit - 43% of male victims and 41% of male perpetrators were unemployed (male unemployment rate in Detroit 11%) 73% of male perpetrators and 69% of male victims also unmarried. A lack of resources and inability to attract long term mates appears to lead to social competition and male –male homicides. Loss of status – one of key motives in male – male homicides appears to be defence of status in peer group. We used to live in small groups - loss of status could have been catastrophic for survival and reproduction. So although it is maladaptive now it still occurs (genome lag) Sexual jealousy A key motivation in same sex aggression and homicide – usually male – male. A summary of 8 studies of same sex killings involving love triangles 92% were male – male and only 8% female – female –Daly and Wilson. AO2 As humans face been killed in different ways; status conflict, jealous mate, sexual rival – would expect evolution of anti-homicide defences e.g. reading the signs of homicidal intend, killing in self defence. Once these evolve homicide becomes a more costly strategy. Duntley and Buss – success rate becomes lower and attempts to kill more dangerous, so homicide gives decreased fitness benefits to killer. Selection would therefore favour development of deceptive strategies to conceal homicidal intent to avoid activating homicidal defences. Limitations – cannot explain why people react in such different ways when faced with the same problem e.g. Buss and Shackelford - 3 men confronted with wives infidelity, one results in beating, one in a homicide and one in getting drunk. Nor can it explain why some cultures e.g. Yonomamo of S. America seem to require male violence to attain status and in others e.g. Kung San of Kalahari – aggression leads to irreparable reputational damage (B and S)