evolutionary explanations of aggression

• An evolutionary explanation of aggression is based on the premise that the human brain is a product of evolution by natural selection. A number of adaptions are needed to cope with various challenges associated with group living. Aggression is a strategy that would have been effective for solving a number of adaptive problems among early humans like gaining resources or competition for a mate. Solving these problems enhanced the survival and reproductive success of the individual, as a result this would be spread through the gene pool.
• Mental models have evolved in response to particular selection pressures faced by ancestral humans. They ‘tell us what to do’ in order to deal with situations similar to those faced by ancestral humans, such as territory or food being scarce. Ancestral males seeking access to females would have had to compete with other males. One way of eliminating the competition would have been through aggression. Those individuals who used aggression successfully against competitors would be more successful in acquiring mates and therefore will pass on their genes to offspring.
• Puts 2010 argues that various male traits seem to imply that this competition did occur in the past. For example, men have 75% more muscle mass than women and are far more aggressive and more likely to die aggressively. Males also have thicker jawbones suggesting they hit each other and the successful passed on the stronger bones.
• Male aggression can occur as a result of sexual jealousy. Men can never be certain they are fathers of their children and so men are always at risk of cuckoldry, the reproductive cost that might be inflicted on a man as a result of his partner’s infidelity. Buss suggests that males have a number of strategies, evolved for the purpose of keeping a mate. These include use of violence to prevent her from straying, as well as violence towards a love rival. Dell concluded that sexual jealousy accounted for 17% of all cases of murder in the UK. Men are predominantly the perpetrators and the victims.
• An evolutionary explanation for warfare would lead us to expect that any behaviour associated with warfare would have evolved because of the adaptive benefits for the individual and their offspring. Displays of aggressiveness and bravery are attractive to females. Male warriors in traditional societies tend to have more sexual partners and more children suggesting a reproductive benefit.

   
• It's argued that the difference in aggressive behaviour may be the product of different socialisation experiences.

  It was found parents are more likely to physically punish boy for bad conduct, but explain to girls what they did wrong. This could increase male violence. Girls learn they are less powerful than boys so they adopt other forms of aggression eg damaging someone’s self-esteem.

  This casts doubt on the claim that males alone have evolved aggression as a way of dealing with rivals, females have just developed a different form of aggressive behaviour.
• One issue with seeing aggressive behaviour as meeting challenges of social living is that it sometimes can result in death and injury.

  For example, violent males might be rejected as mates, and warriors might die in war. Therefore, aggression can be considered more maladaptive than adaptive in some cases. However, Duntley and Buss point out benefits of aggression must have outweighed costs on average relative to other strategies in evolutionary past.

  If this is the case, natural selection will favour the evolution of aggressive behaviours making them fundamental parts of human nature.

   
• An issue with the evolutionary explanation is that it is overly deterministic.

  The explanation is based on the human brain being a product of evolution and therefore, aggression is adaptive in all humans. However, not all aggression is the same between everyone. For example, some people are much more aggressive than others, and some show aggression in different ways.

  Therefore, there must be other aspects that create aggressive behaviour as well as a potential evolutionary past influence.
• A strength is the support for the link between aggression and status.

  In industrialised societies such as the US, most violent gang members often have the highest status between their peers. Males also display a heightened sensitivity to perceived affronts to their status and reputation, such that many acts of male on male violence results from 1 male perceiving an issue with their status from another male. This suggests that not only is aggression and important way of gaining status but also a consequence of threats to that status.