Evolutionary explanations of aggression

Evolutionary explanations of aggression
Evolutionary psychologists argue that reproductive challenges faced by our ancestors can explain the aggressive behaviour seen in people today. A man can never be certain that he is the father of his wife’s children unless he prevents her having relationships with other men. This can explain why male jealousy is often cited as a cause of domestic violence.
In many countries it is seen as acceptable to murder an adulterous wife or her lover e.g. among the Nuer people of East Africa, a man who commits adultery is likely to be killed by his lovers husband, and only 35 years ago in the USA a man who killed his wife’s lover while in the act would have a legal excuse for murder and be unpunished.

According to Daly and Wilson, men have evolved different strategies to deter their partners from committing adultery, ranging from vigilance (watching their every move) to violence. All of these are the result of male jealousy and paternal uncertainty (being unable to be certain he is the father of her children). If a man’s partner is unfaithful and has a relationship with another man, he runs the risk of cuckoldry (that he may unwittingly invest resources in rearing children that are not his own). Male sexual jealousy may therefore have evolved to prevent infidelity by woman and reduce the risk of cuckoldry.
Buss et al argues that males have developed strategies for mate retention. These include direct guarding (restricting her movements) of the female and negative inducements to prevent her straying (financial control, threat of violence if they are unfaithfull or even so much as look at another man, etc.)
Wilson et al found support for the link between sexual jealousy, mate retention and violence. In an questionnaire, women who indicated that their partners were jealous did not like them talking to other men were twice as likely to have experienced violence from their partners (72% of these needing medical attention)
An important implication of research into sexual jealousy and violence is that mate retention techniques (e.g. direct guarding and negative inducements) can be the early sign of a violent man. Educating people in these danger signs can reduce the likelihood of women becoming victims of violence.
If men can prevent female infidelity by giving their partners positive benefits to stay they are less likely to be violent, but men who are unable to provide positive benefits are more likely to become jealous and violent leading, according to Daly & Wilson, to the unintended killing of the woman. Daly and Wilson proposed this was the unintended outcome of an evolutionary adaptation that was intended for control rather than death.
Murder represents the most extreme form of aggression and the statistics around the world show that the majority of killers are men. One explanation for this suggests lack of resources may lead to increased male to male aggression as females are believed to be attracted to males who have vast resources thus increasing the chances of murder to eliminate rivals. Supporting evidence for this comes from murder statistics in Detroit USA when 43% of victims being male and 41% of perpetrators being unemployed.
A threat to male status appears to offer another explanation for homicide. One of the key reasons male-to-male killings appears to be through the defence of status within social groups of individuals. A possible explanation is that humans evolved in small groups and the loss of one status within such small groups could have led to catastrophic problems for survival and reproduction. Such behaviour is obviously maladaptive in the modern world however such mechanisms may still continue to operate and also be triggered by events that may have activated them in the past also.
Sexual jealousy is another possible reason for homicide due to the link between infidelity and cuckoldry with men being the biggest victims and perpetrators of murders. Daly & Wilson summarised data from 8 studies involving “love triangles” and found that 92% of the murders involved males killing males and only 8% involved females killing another female supporting such a possible explanation. However, a methodological problem with this study is the relatively small sample making wider generalisation difficult.
Shackleton et al demonstrated the link between mate retention, jealousy and violence. They surveyed 461 men and 560 women who were all in committed heterosexual relationships. The men answered questions about their use of mate retention techniques, and the women were asked about their partners’ use of mate retention techniques and how violent their male partners were. There was a positive correlation found between men who used mate retention techniques of direct guarding and negative inducements and their use of violence. Men also tended to use emotional manipulation as a mate retention technique. The women‘s results confirmed this as there was also a positive correlation between those that had jealous partners and being the victims of violence.
A limitation of the evolutionary approach is that it fails to properly explain why males tend to react in very different ways when faced with the same problem e.g. a wife cheating. For example, as Buss and Shackleford highlight, when confronted with their wives infidelity men react in very different ways as some may be violent; others may give in to her every desire to attempt to keep her while others may simply avoid the issue by getting drunk or even leaving the relationship entirely.
Murder as an adaptation theory is supported by comparison studies of other species and animals. Among mammals for example, there is a well-documented cases of conspecific killing. For example male lions and cheetahs have been observed to kill the cubs of rival males with the advantage being an increase in the killers own adaptive fitness and allowing such male lions to mate with the infants mother with their own offspring. Also among primates the killing of rival adult males has also been evidenced among mountain gorillas.
Most studies of infidelity have focuses solely on the males mate retention strategies and men’s violence against women. Women have also been found to engage in aggression and mate retention tactics and also behave very violently towards their partners. Research by Archer suggests women initiate and carry out physical assaults on their partners as often as men and family conflicts studies have found equal rates of assault between males and females. This demonstrates there is a great deal of gender bias with such theories that seem to suggest that most of the violence is caused by men when evidence suggests otherwise.
Evolutionary explanations of infidelity and jealousy suggest aggression is down to evolved responses and genes, which is reductionist and oversimplifying human behaviour. Such explanations ignore the role of cognitive factors and are deterministic as they ignore the role of free will and people’s ability for conscious thought which can override such behaviour should they wish. Proving aggression is down to evolution in itself to do making the theory flawed