The evolutionary theory states that a human’s main aims are to survive long enough to pass on their genes, and to ensure that those genes live on in their children. If the desire to achieve these goals is not met, or is threatened; humans can become aggressive.
Men are more likely to experience sexual jealously because of their fear of cuckoldry, the reproductive cost that might be inflicted on a man as a result of his partners infidelity. Because men are more prone to parental uncertainty, they risk unwittingly investing resources in children who aren’t their own. Sexual jealousy and the aggression which it can cause, therefore, evolved to deter females from sexual infidelity and hence minimise the risk of cuckoldry.
To do this, men have evolved retention strategies to deter mates from infidelity. This includes direct guarding, in which a male is especially vigilant to their mate in order to restrict her sexual autonomy. Retention strategies can also include violence against the woman. In extreme cases, an unintended consequence of this evolutionary behaviour may be her death.
Male jealousy is claimed to be the single most common motivation for killings in domestic disputes in the US (DALE ET AL). DELL concluded that sexual jealous accounts for 17% of all cases of murder.
Research has supported the relationship between male retention strategies and violence. SHACKELFORD-Results showed that males used two main violent forms of technique to retain the females these were; shouting at their partner for looking at other males and direct guarding (i.e. monopolizing her time at party for example). Men also were reported to emotionally bully females i.e. by making them feel guilty by threatening to kill themselves. Women also agreed that men who were more emotionally manipulative were also more violent towards them. In the Shackelford study, data was collected using a survey technique. Surveys have particular problems, especially when used in sensitive areas, such as violence against a spouse. Answers may not be truthful because of social desirability bias. As the research was correlational it meant that no casual relation could be established between mate manipulation techniques and aggression.
A problem for these evolutionary explanations of aggression is that most studies of infidelity have focus solely on men’s retention strategies and violence against women. It has been argued that women practise retention strategies and carry out assaults on their partner as often as men do. This would suggest that out current understanding of mate retention strategies is limited due to this gender bias.
This understanding has a real world application. The use of mate retention strategies can be seen as an early indicator of potential partner violence. It therefore has value in alerting others to intervene before actual violence against the partner can occur.
There are limitations to this evolutionary explanation, such as the fact that there are individual differences. This approach cannot explain why some men react differently to the same stimulus. This suggests that violence is not a universal response to sexual jealousy and thus that it is not completely evolutionary.
This perspective is also unable to explain why, if there is a universal human response to these situations, there are culture differences in the importance of violence. For example, in some places male violence is required to attain status but in others aggression only leads to reputational damage.
Males however, are more concerned with sexual infidelity. If a woman is sexually unfaithful, her partner is at risk of raising another man’s child. Men do not want to invest resources in a child who does not possess their genes. A man would therefore become jealous if he suspected his female partner was being sexually unfaithful. This can lead to physical aggression, and has explained why some men harm their partner’s child from a previous relationship.
There is evidence to support this theory, provided by GARY BRASE’S research comparing sexual jealousy across cultures. It was found that Brazilian males are the most jealous, compared to the far less jealous Japanese men. A positive correlation was observed between the level of jealousy and fertility rate (high in Brazil, low in Japan). This may explain the sexual jealousy in these countries; as in a country with high fertility a woman is more likely to get pregnant following intercourse, making faithfulness more significant.
Another problem linked to male violence is sexual infidelity. SHIELDS ET AL found that female victims of partner crimes were more likely to have reported engaging in extra marital sex than women who had not been raped by their male partners. Men can guard against their partners infidelity either by conferring benefits or by conflicted costs including violence. According to DALE ET AL, death of the parent from physical violence may be an unintended outcome of an evolutionary adaptation that was designed for control rather than death.
Evolutionary explanations are regarded as speculative; they cannot be empirically tested as the basis for them occurred thousands of years ago. They would therefore not fulfil Popper’s criteria of what constitutes a science e.g. falsifiability, so the explanations could not be deemed scientific.
Also, some of the explanation is not plausible. A female directing aggression to her partner if she thinks he has been unfaithful may drive him away and is therefore not an adaptive response.
Cultural differences in murder rates of wives by husbands and in the anxiety felt in response to sexual infidelity also indicate that factors other than evolution play a part in jealousy related aggression; suggesting that the evolutionary explanation reductionist. It may therefore be logical to take a more interactionalist approach, accepting that multiple factors (e.g. disposition and socialisation) all influence aggression.
Some critics also argue that evolutionary explanations justify violence against women as natural and inevitable. This is an unfair assumption to make in the modern world, and is also deterministic, as it states that males are victims of their evolution, therefore disregarding the role of free will land self-control in our behaviour
Also, much research supports the idea that the causes of jealousy vary between the sexes. For example, BUNK found that men focus on physical fidelity, and women focus on emotional fidelity. However, recent findings from HARRIS (meta a of 32 studies) challenge this, as it was found that both men and women are deeply affected by emotional infidelity. This indicates that the evolutionary theory may need to be re-evaluated, so that it applies to our modern society.
Another problem is that evolutionary theory is post-hoc (after the fact) theory. This means that it only explains aggressive behaviour after it has happened rather than making predictions about what is going to happen via testing.