Chap 10: Aggression

What 6 adaptive problems could aggression have evolved to solve?

1. Take resources from others

2. Defend against attack (eg. political wars)

3. Inflict costs on intrasexual rivals (eg. hockey fight)

4. Negotiate status and power hierarchies (to increases status)

5. Deter rivals from future aggression (eg. setting up defenses)

6. Deter LT mates from sexual infidelity; mate guarding

What does it mean when aggression adaptions are context-specific?

Aggression is not the only solution to these adaptive problems

What are the 4 costs of aggression?

1. Risk of injury or death

2. Bad reputation

3. Retaliation by victim

4. Retaliation by victim’s allies and kin

What is the recalibration theory of anger?

When someone places too little weight on your welfare, the expression and feeling of anger acts to increase (recalibrate) the value that the target places on your welfare

Which 2 groups of people are more prone to anger?

1. Men with greater upper body strength (but not women)

2. Self-rated physically attractive men and women

What 3 things do these 2 groups of people have higher of?

1. Success in social conflicts

2. Utility in using aggression

3. Greater sense of entitlement

What are 2 reasons why men are more violently aggressive than women?

1. Males need to compete for valuable mate access (// parental investment theory)

2. Compete to gain status as a man's reproductive success is highly varied based on his status

What are 2 outcomes males engage in aggression to achieve?

1. To “win big” (eg. gaining access to multiple mates or reputation that leads to multiple mates)

2. Avoid total reproductive failure

What is an animal species in which mating success is determined by aggression (who is stronger, bigger)?

Elephant seals

What is a related characteristic of elephant seals?

They are sexually dimorphic (observable differences in physical appearance of males and females of the same species) - males are 4X larger than females

Which type of aggression do women engage in more?

Indirect, non-physical aggression (eg. social exclusion, gossip)

What are the gender differences in same-sex bullying instances?

• Boys: more of them are bullies and get physically hurt more

• Girls: more of them had been called nasty names, and were victim of rumours

According to Janet Hyde’s meta analysis of sex difference, what is revealed about adaptive patterns in aggression?

Men score higher on different manifestations of aggression (eg. fantasies, physical, imitative, willingness to shock others)

What is an exception to that?

Hostility (women and men are similar on that)

What specific type of homicide has men committed consistently higher of across countries (vs women)?

Same-sex homicide; male-male homicide dominance

What is the young male syndrome?

The highest rates of homicides were committed by young men in their 20s

What can explain that?

Strong selection pressure for males in their 20s to compete for status and reputation

What are the 3 possible contexts that could trigger men’s aggression against men?

1. Martial and employment status

2. Honour and reputation

3. Intrasexual rivalry

Which type of men are more likely to commit killing (other men)?

Poor, unemployed and unmarried men (people at the bottom fighting e/o)

What is an evidence that supports the evolutionary importance of defending honour?

Motives of face, reputation and status account for more than half of murders in Japan from the 1950s -1990s

What is an evidence that supports men’s higher aggression related to sexual rivalry?

92% of same sex love-triangle killings are by men

What do women derogate e/o on?

Physical attractiveness and promiscuity

What is the most common cause of male aggression toward females across cultures?

Sexual jealousy

What is a large % of spousal homicides and beatings attributed to? (Gayford, 1975)

Extremely jealous husbands

Which type of wives/girlfriends are more likely to be killed?

Young wives & girlfriends (compared to older ones)

What are 2 possible contexts that could trigger women’s aggression against men?

1. Self-protection against husband enraged over real or suspected infidelity

2. Protection of children

What is the gender difference in reported homicidal fantasy?

Higher % of men (79%) than women (58%)

What are 5 possible contributing reasons to homicidal fantasies?

• Personal threat

• Got robbed

• Desire to know what it’s like to kill

• Conflict over money

• Public humiliation

What is a characteristic of men’s fantasies?

They are more detailed and last longer

How do the byproduct & adaptation hypothesis explain the evolutionary origins of homicides?

• Byproduct: homicide is a byproduct of violence used for coercive control

• Adaptation: evolved homicide mechanisms