Evolutionary Explanations of Human Aggression

Evolutionary Explanations of Human Aggression

1. Jealousy

   • Cuckoldry and Sexual Jealously
     • Cuckoldry refers to the reproductive cost that may be inflicted on a man as a result of his partners infidelity.
       • The consequence of it is that a man may unwittingly invest his resources in offspring that are not his own.
         • The adaptive functions of sexual jealously, therefore, would have been to deter a mate from sexual infidelity, thus minimising risk of cuckoldry
   • Mate Retention and Violence
     • Males have a number of strategies that have evolved specifically for the purpose of keeping a mate. These include violence or the threat of violence (BUSS)
       • Studies of battered women show that in the majority of cases, women cite jealousy as the key cause for violence towards them (Dobash and Dobash)
   • Sexual Jealousy and Extreme Violence
     • Male sexual jealousy is claimed as the most common motivation for killings in domestic disputes in the US and UK, with men being predominantly the perpetrators and the victims.
       • A summary of 8 studies (Wilson and Daly) of same sex killings involving 'love triangles' found that 92% were male-male murders and only 8% female-female.

2. AO2/3

   • IDA: Gender Bias
     • Most studies of infidelity have focused on the men's mate retention strategies and male violence against women.
       • However, this view is gender biased because women also practice mate retention strategies and engage in violence against their partner.
         • Example: Felson found that women were twice as likely to murder out of jealously as were men.
   • Relationship between Sexual Jealously and Violence
     • Shackelford et al: Found a clear relationship between sexual jealously, the use of mate retention strategies and violence towards women.
       • Buss and Shackelford: Found that men who suspected their wives might be unfaithful over the next year use greater punishment for a known or suspected infidelity than did men who did not expect future infidelities.
   • IDA: Real World Applications
     • The use of mate retention tactics by males can be an early indicator of violence against a female partner.
       • The findings from these studies suggest that awareness of the use of mate retention strategies by the male partner can be used to alert friends and family members to the danger signs that violence may follow.
         • At this point, help can be sought (or offered) before inter-mate violence ever happens.
   • There is Physiological Basis for Jealously - Based Aggression
     • Takahashi et al: Found that the neural response to imagine scenes depicting sexual infidelity and emotional jealousy were different for men and women.
       • Men had a greater activation in amygdala and hypothalamus when presented with scenes depicting sexual infidelity in their mate.
   • Research Doesn't Tell the Whole Story
     • Edlund and Sagarin: Claim that our understanding of the relationship between sexual jealousy and aggression is limited as it doesn't tell us if the locus of responsibility (female partner or other male) influences the amount of jealousy experienced and therefore degree of violence.

3. Infidelity

   • The detection or suspicion of infidelity is a key predictor of partner violence - Daly et al.
     • Sexual Coercion
       • A consequence of a men's perceptions of infidelity in their partners sexual coercion or partner rape - Goetz et al.
         • Sexual assault of a female by her mate is directly linked to the perceived risk of her infidelity (Camilleri). Female victims of partner rape are likely to have engaged in extra - marital sex (Shields and Hanneke)
     • Violence towards Pregnant Partners
       • A man risks lowering his reproductive success if his partner becomes pregnant with another man's child.
         • A function of violence directed towards an unfaithful female may, therefore, be to terminate the pregnancy to eliminate the potential offspring of a male rival.
     • Uxoricide (Wife Killing)
       • Men can guard against their partners infidelity by either conferring benefits or inflicting costs (such as violence).
         • As not all men possess resources that might be used to provide benefits, some men are especially prone to the use of violence instead.
           • Daly and Wilson argue that death of partner as a result of physical violence is an unintended consequence of an adaption designed for control rather than death.

4. AO2/3

   • Research support for link between infidelity and partner violence
     • Camilleri: Used a survey method and found that the risk of a partner's infidelity predicts sexual coercion among males but not among females.
       • This is significant as only males are at risk of cuckoldry.
         • Camilleri and Quinsey also discovered that men convicted of raping their partners were more likely to have experienced cuckoldry risks prior to their offence compared to men convicted on non-sexual partner abuse.
           • Problem with Surveys
             • Many of the studies in this area use surveys, but these have their problems. Answers may not be truthful because of social desirability.
               • Over report desirable behaviour and under report undesirable behaviour.
     • Evidence of violence towards pregnant partners
       • Burch and Gallup: Found that acts of violence towards pregnant mates was double that toward non-pregnant mates, with sexual jealousy cited as the main reason for this difference.
         • Taillieu and Brownridge: Found that women abused while pregnant were more likely to be carrying the child of someone who was not their mate.
           • Valladares et al: Found that half the women abused while pregnant had blows directly to their abdomen, presumably designed to increase of aborting the foetus.
     • Limitations of Evolutionary Explanations
       • Cannot explain why people react in different ways when faced with the same adaptive problem
         • Buss and Shackelford: Suggest that although some men may react to infidelity with mate retention strategies, or even murder, others will respond less violently.