Aggression as an adaptive response.

Infidelity & JealousyMurder

Group displays.

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Key words

• Reproductive fitness• Natural selection• Adaptive• Jealousy• Cuckoldry• Conspecifics• Lynch mobs• Deindividualtion• Power-threat hypothesis• Group Displays

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Evolutionary explanation of aggression.

What do they all have in common?

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Answer: Reproductive fitness

• On the previous slide all the males have been defined by their reproductive fitnessreproductive fitness, that is they have adopted traits that were successful that have been passed on by our ancestors.

• Natural selectionNatural selection effectively weeds out characteristics that confer no advantage for survival & reproduction & selects those that do!

• These are known as adaptive traits...in this case we are referring to male sexual male sexual jealousyjealousy.

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It makes sense.....right????• Primary motivator is

acquisition of status.• In the EEA, good hunters

accrued resources and skilled fighters could ward off rivals = ATTRACTIVE TO FEMALES.

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NOT

The ages of man…reworked!!

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Sexual Jealousy and Infidelity in Males

MALE ON MALE AGGRESSION•Daly & Wilson (1985) – 58 / 214 cases of murder motivated by sexual jealousy.•Confidence in paternity and warning to potential rivals

MALE ON CHILD AGGRESSION• Link to parental investment• Males reluctant to expend energy and resources in raising offspring of another male.• BUT refer to bad dad / good step-dad study…

MALE ON FEMALE AGGRESSION• Designed to deter the female from indulging in behaviour not in the male’s interest. • Miller (1980) – 55% battered wives cited jealousy as reason for husband’s behaviour.•Often unfounded, based only on suspicion and fear.

Infidelity & Jealousy

• Daly & Wilson(1988)Daly & Wilson(1988)• Men have evolved

mate-retention strategies.

• Mate retention strategies enhance reproductive fitness.

• Vigilance-Violence• Direct guarding-

snooping.

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Young (1978)

• Asked students to describe their likely reactions to a jealousy inducing scenario

• Men – respond angrily, become drunk, threaten their rival.

• Women – cry, pretend not to care, try to increase own attractiveness to regain male attention.

What about female jealousy? Aggression

in females• For females, the costs of aggressive behaviour exceed the benefits.

• The mothers’ presence is more critical to offspring survival than the father’s. (Campbell 2002)

• High status, dominant, aggressive females not preferred as mates so no adaptive value in overt aggression.

• BUT low risk, indirect strategies such as gossiping, name calling and ostracising to decrease attractiveness of competing females

developed to reduce risk of physical injury.

Better to remain

the good little

wifey!!!Less physical...just as

aggressive????

• Griskevicius et al (2009) gave students scenario of person of same sex spilling a drink on them at a party and not apologising .

• Majority of men would respond with direct aggression (eg, pushing the other man)

• Only a quarter of women would do so, most women most likely to walk away.Women most likely to use direct aggression when competing for resources that will aid their survival

Who’s da baby’s daddy???

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http://www.youtube.com/watch?v=okQsrwMhFjU&feature=related

Cuckoldry & Sexual Jealousy

• Looking after another mans child (unknowingly!!)

• The risks are high for the females (Loss of partner/retaliation).

• Platek & Shackleford (2006) suggested that men lose the opportunity to reproduce and invested resources…hence why they become quite upset when the secret is revealed!!!!!!

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Conspecifics.

• The killing of young of another...e.g. Leo the Lion!

• How might the killer benefit from his actions?

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Q: What do Gorillas and lions have in common?

A: Killing by Conspecifics.

• You would need to calculate:

• The reproductive fitness of both the killer and the killed and how it might change.

• So how would a lions reproductive fitness change as a result of killing another males cubs?

• What about a Dominant male gorilla?VIRTUALPSYCHOLOGY.CO.UK

The evolution of murder.

• The UK defines murder as:• ‘Taking a life with the• intention to kill or do serious harm.’

• Recent murder statistics are as follows: 1 in 15000 are murdered in the states (Stolinksy & Stolinksy 2000).

• This equates to 1 in 200 chance of being murdered in our lifetime (75 year lifespan).

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An adaptive response.

• Buss & Duntley (2006) proposes we have traits that have evolved thrgh natural selection and these behaviours are activated by certain factors:

1. The degree of genetic relatedness between killer and victim

2. The relative status of the killer & victim3. The sex of the killer & victim4. The size & strength of the killers & victims

families & social allies.

We would not still have murder as part of our traits if it were not associated with greater reproductive success than competing strategies.

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Buss and Duntley cont….

• Murder was a function that solved problems such as:

• Preventing harm- Rape or killing of an individual, their families or mates by others of the same species.

• Reputation Management- Avoiding being perceived as easily exploited, injured or rape.

• Protecting resources- Territory, • shelter or food.

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Predisposing factors for murder.Predisposing factors for murder.Daly & Wilson (1988).

Nature of murder Frequency

Male offender/male victim

65.3%

Male offender/female victim

22.7%

Female offender/male victim

9.6%

Female offender/female victim

2.4%

Source: FBI supplementary homicide reports 1976-2005VIRTUALPSYCHOLOGY.CO.UK

Daly & Wilson…..a closer look!!

The results illustrate:1. Men alone are not restricted to murder.2. Different reasons were given for murder

by men & women.3. Men are more likely to kill a love rival or

those who threaten their dominant position.

4. Women are more likely to kill through self defence e.g. Murdering partner who sexually abused them.

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Wilson & Daly (1985)

• An earlier study found murders tended to be age related too, with males peaking in their early 20s

• Q. What does this coincide with?

• Further to this evidence theories have been proposed that have suggested the following are factors for competition in reproductive success………

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Factors…..• Threats to male status-Threats to male status- Maleness then youth are the two single

most important factors. Every girl likes a bad boy! And when competition is high for scarce resources violence can occur.

• Loss of male status would be catastrophic for the survival & reproduction of our ancestors. We therefore have mechanism in place to prevent this loss.

• Lack of resources-Lack of resources- Females are attracted to males who have resources. ( Look at the song lyrics below…..)

• “I don’t want no scrub, a scrub is guy who cant get no love from me, sitting in the passenger side of his best friends ride tryin’ to holler at me!”

• “Aint nothin’ goin’ on but the rent, you’ve got to have a J -O - B if you wanna be with me!”

• SexualSexual jealousyjealousy--Between cuckoldry & infidelity men can be both victims and perpetrators. Wilson & Daly 1988 summarized data from eight studies & found 92% of murders in a same sex love triangles involved males killing males vs. 8% of females vs. females. VIRTUALPSYCHOLOGY.CO.UK

Evaluation of murder explanation.

• Comparative evidence (Ghigleri 1999)- Conspecific killing is common in animal kingdom.

• The female will come into oestrus sooner can be impregnated with the killers own offspring.

• In Gorillas (Fossey 1984) it has also been well documented that rival males will kill competition for dominant male role.

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Evaluation of murder explanation.

The evolved goal hypothesis- • Humans have evolved motivation for specific goals such as status,

that were associated with greater reproductive success among our ancestors.

• + = Reproductive success!

• We use a sort of Cost:Benefit analysis (Hardy 1999) we use to assess what behaviour would be most appropriate in specific situations. It may be deemed as appropriate to result to murder to achieve a certain goal. Therefore we would not need a an evolved mechanism to engage in in a specific behaviour.

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Further implications-A stretch• What further implications could

murder have on inclusive fitness & why????

• A stretch & challenge activity…you don’t need to know this but having this information will illustrate depth & breadth of your knowledge!!!VIRTUALPSYCHOLOGY.CO.UK

An overall evaluation of aggression as an evolutionary response.

Cultural differences- Fails to explain why some cultures require violence to attain status (Yanomamo of South America) in comparison to more peaceful cultures (Kung San of the Kalahari).

Differences in the reaction of men to infidelity (debasement inter-sexual violence!)

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What about group displays

Lynch mobs??• Killing a person for

a presumed offence without the legal authority to do so.

• There may or may not be planning behind the attack.

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What about group displays. sporting events....

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•http://www.youtube.com/watch?v=tdMCAV6Yd0Y&NR=1

Winning team hold high status,

team members seen as desirable mates.

• In certain games (eg, rugby union) a level of aggression is sanctioned but some players still break the rules.

• Maxwell & Viscek (2009) – questioned 144 rugby union players about their aggression in the game.

• Those high in professionalism placed more emphasis on winning and were more likely to use unsanctioned aggression.

• Cheating (and not getting caught) is adaptive. Victory in matches also brings status to fansCialdini et al (1976) ‘basking in reflected glory’ – after a university football team had performed well, students more likely to wear university scarves and sweaters.

Or could it be...

• Marsh (1978) – football hooliganism is human equivalent of ‘ceremonial conflict’ in animals.

• Exclusively male, ritualised symbolic aggression restrained by desire to minimise harm and death.

• Intention is to humiliate opposition and secure submission.

What about Football hooliganism???

Is this a realistic interpretation though? Research instances of football hooliganism to

criticise this view.

For A02 marks, you could offer deindividuation theory as an alternative explanation for both types of group display.

Group Displays: Religion/cultural displays

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• Aggression during religious/cultural displays.

• This behaviour signals commitment to the group.

• I.e. Self-flagellation

Religious/cultural displays

• Self inflicted violence is not uncommon- self flagellation during Ashura. A recreation of the suffering of Hussein grandson to Mohammed the prophet.

• They use knives/chains until they bleed.

• A committed member of the group is a cooperative member. By engaging in these rituals an individual is cooperating and being committed.

• Natural selection would have favoured their development.

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The power-threat hypothesis.

• Blaock (1967) suggested that as a minority group membership grows a majority group fights harder to maintain dominance.

• Tolnay & Beck described Black lynching's as

• “Trying to vote” & “Voting for the wrong party”.

• As the minority grp percentage increases so does the groups discriminatory behaviour.

• Thus the fear of Negro power meant white mobs frequently resulted to lynch law as a means of social control.

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Dehumanisation • Hysterical desecration Hyatt (1999) claimed was a method of getting

rid of bits of bone & flesh.• Tolnay & Beck (1995) suggested Blacks were, in the minds of whites,

reduced to stereotypes and debasing stereotypes further dehumanised victim –void of worth.

• By branding Blacks in this way the whites were ‘defending their white community against black brutality’.

• Therefore lynching could be seen as an evolved adaptation to perceived threats.

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Q: But what about the lone rangers!!A: A price has to be paid!!

• An individual who reaps the benefits but contributes little or nothing.

• Physical costs: Israeli summer- You have to be really committed, the intensity of the activity is too much for low quality individuals to participate thus showing good indicators of things such as status & breeding.

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