However, research in mate aggression was conducted by Buss and Shakelford on male and female aggression. They examined mate-retention tactics in married couples. Compared to women, men reported a higher use of intrasexual threats (violence to another man) whereas women reported a greater use of verbal possession signals. They also found that, men with younger female partners devoted more effort in retention tactics, including violence to rivals and threats to the female partner.
Supporting research was completed by Shakelford; they used a survey method to test predictions concerning the use of male retention strategies. As expected males use of retention strategies was positively correlated with violence scores against their mate. In addition, their use emotional manipulation as a mate-retention strategy also predicted their violence against their partner. However, there are many methodological problems with male retention studies. Shackelford et al admitted their research to have limitations as their research was correlational which means that cause and effect cannot be inferred between male retention strategies and violence. Furthermore, Shackelford’s survey method provides issues because it may encourage social desirability bias because violence may be a sensitive area within the individual and they may lie to avoid complications. This then leads to underreporting of undesirable behaviour reducing strength of the research and makes us question how valid the research is.
Buss and Duntley propose that humans possesses adaptions that have evolved specifically through the process of natural selection to produce what we now refer to as murder. Buss and Duntley claim that for our ancestors, murder was functional in solving many problems like preventing harm from others, keeping reputation and protecting resources. In conclusion, these problems may trigger aggression to the extent of murder.
There is evidence from cross-cultural research that supports the claim that may incidents of male-killing are a consequence of jealousy. For instance, Daly and Winson found that a common theme was that all jealousy was initiated by comments on the attractiveness of another man’s wife. However, buss and Shakelford claim that an evolutionary perspective on murder cannot explain why people react in different ways when faced with the same problem which shows there must be other factors that cause aggression.
Overall, there are many issues with the evolutionary theory. Firstly, the approach is reductionistic as it fails to consider other approaches such as the psychodynamic approach and suggests that aggression is down to genetics; however, that cannot be the case because if it’s all down to genetics, everyone would show aggression, but that’s not the case. In addition, most of the research conducted into the evolutionary theory is on animals; humans are more complex and therefore we cannot generalise the findings from animal to humans as their will be differences in behaviour. Similarly, the approach androcentric; the majority of research is with men and doesn’t explain why some females can be aggressive. Moreover, the approach is also deterministic because it assumes that all aggression is down to genetics and doesn’t take into consideration free will and how some events may make people angrier consequently leading to aggression. And lastly, the approach has socially sensitive research. By concluding that aggression is caused by aggression it may affect crime sentencing by reducing the punishment; this then has consequences for society.
In conclusion, the evolutionary explanation is weak. It fails to consider a large number of other factors and approaches that could also be the cause of aggression. For instance, the approach fails to consider any factors from approaches such as the social learning theory which suggests that aggression is caused not only by inherited factors but also environmental factors such as reproduction which is copying (aggressive) behaviour you have witnessed. Despite being very reductionistic, the approach does have a lot of supporting research for how jealousy can be a cause for aggression but is mainly male focused and therefore cannot explain why everyone is aggressive.