HC 7 Flashcards
Why aggress?
6 volutionary functions
1 • Co-opt resources of others 2 • Defend against attack 3 • Eliminate sexual competition 4 • Climb up the hierarchy 5 • Deter rivals from future aggression 6 • Deter infidelity
Aggression as a Solution to Adaptive Problems
(1) Co-opt the Resources of Others
Humans stockpile resources valuable for survival and reproduction • Fertile land • Fertile women • Access to – Water – Food – Tools – Weapons
Aggression as a Solution to Adaptive Problems
(2) Defense against Attacks: 2 ways
1 – Aggression can be used to defend against attack
• Prevents one’s resources from being co-opted by others
2 – Social exclusion as defense mechanism
Aggression as a Solution to Adaptive Problems
(3) Inflict Cost on Intrasexual Rivals: 3 outcomes
– Same-sex rivals are vying for same (or similar) resources
– Aggression can inflict cost (verbal, physical) to same-sex rivals —> reducing desirability of victim to members of the opposite sex
– Direct versus indirect aggression (sex difference)
Intra sexual competition
- The more intra sexual competition, the more sex dimorphism
- The more polygynous, the more sex dimorphic a sex.
- Gorillas: males +/- 100% bigger
- Chimpanzees: males +/- 38% bigger
- Humans :males +/- 18% bigger
Aggression as a Solution to Adaptive Problems
(4) Negotiate Status and Power Hierarchies
Aggression can be used to increase status or power within existing social hierarchies
• Prevents one’s resources from being co-opted by others
• Bullying as a dominance strategy
Aggression as a Solution to Adaptive Problems
(5) Deter Rivals from Future Aggression
Aggression can cultivate a reputation that may deter others from attempts at co-opting
Aggression as a Solution to Adaptive Problems
6) Deter long-term mates from infidelity ((3)
• Domestic violence
• Jealousy as mate retention strategy:
– Male sexual jealousy and female emotional jealousy (Buss, 1999; Buunk et al., 1996);
• Homicide of wife by husband accounts for 1/3 of murders in USA
Theory of rape
- Rape as mating strategy in many species (e.g., ducks, urang-utans)
◦ especially for males with very few resources to get normal access to women - Does this apply to humans?
◦ Sexual coercion as adaptation or byproduct
The Context-Specificity of Aggression (2)
– Aggression should only be triggered in contexts
that present the adaptive problem
– Culture of honour studies suggest cultural differences
Why are men more violently aggressive than women? (3)
Intrasexual competition
• Parental investment: men lower than women
• Sexual selection and greater variance in men than women to reproduce
• Evolution of “risk-taking” among men, more strongly than women
The young male syndrome (Wilson and Daly, 1985)
• Why would men die more often than women?
- Young men seeking a wife need to excel, i.e. risk taking behaviour.
- Carry over effects in reputation for the rest of their life (e.g. war heroes)
“The Crazy Bastard Hypothesis”
The young male syndrome
Empirical work demonstrates a link between physical risk-taking and social perceptions of physical formidability
Body Differences in Design for Combat
• Compared to women, men have…
61 percent more total muscle mass, 75 percent more upper arm muscle mass, 91 percent greater upper body strength, taller bodies, heavier bodies, thicker jaw bones, stronger bones, greater bone density in their arms, higher muscle- to-fat ratio, broader shoulders that facilitate weapon use, and even thicker skin
Bullying
• Same-sex bullying in schools
Males compared to females show increased numbers of • Number of times bullied • Joined in bullying others • Physically getting hurt • Belongings taken away
– Females have increased scores compared to males on
» Name calling
» Spreading rumors
Contexts Triggering Male-Female Aggression
• Sexual Jealousy against woman
– Largely targeted at spouses, mates, girlfriends
– When:
• Observation or suspicion of infidelity
• Women is terminating relationship
– Young females are far more likely to be killed than older females
Contexts Triggering Female-Male Aggression
• Defense Against Attack against men
When:
• Woman is defending herself against a partner who is enraged over a real or suspected infidelity
• Woman who has been in a prolonged physically abusive relationship
Contexts Triggering Female-Female Aggression
• Indirect aggression towards sexual rivals
When and how?
When? – Competition over partners – Friendship disputes – Failing to share resources How? – Gossip – Exclusion
Why violence has declined in society over time? (4)
- empathy
- self-control
- moral sense
- reason
Evolution of Warfare
• Four Conditions
1– The average long-term gain in reproductive resources must be sufficiently large to outweigh the reproductive costs of engaging in warfare over evolutionary time
2– Members of coalitions must believe that their group will emerge victorious
3– The risk that each member takes and the importance of each member’s contribution to the success must translate into a corresponding share of the benefits
4– Men who go into battle must be cloaked in a “veil of ignorance” about who will live or who will die
male warrior hypothesis
Men, but not women, will have evolved psychological mechanisms designed for coalitional warfare
Evidence for male warrior hypothesis (3)
• Men cooperate with ingroup more during intergroup competition
• Men’s groups are more hierarchical, facilitating warfare (van Vugt, 2006)
• In war games men attack more often than women (Johnson et al. 2006)
– Males made more unprovoked attacks
– They were more likely to either attack or retaliate rather than never fight
