Aggression Flashcards
Reactivity of what system predicts aggressive behaviour? What other pats of the brain come under this system?
(i) Limbic system
(ii) Amygdala, cingulate gyrus, hypothalamus.
What did Gospic et al. (2011) find?
Found aggressive reactions were associated with a fast and heightened response by the Amygdala.
How is serotonin related to aggression?
- Low levels of serotonin results in reduced self-control and increased aggression.
In relation to serotonin and aggression, what did Virkkunen et al. (1994) find?
- Compared levels of a serotonin metabolite in cerebrospinal fluid of violent impulsive and non-impulsive offenders.
- Levels significantly lower in impulsive offenders.
What hormone, found in larger quantities than men, is linked to aggression?
Testosterone.
In relation to testosterone and aggression, what did Dolan et al. (2001) find?
- A positive correlation between testosterone levels and aggressive behaviours on male offenders in UK maximum security hospitals.
How do animal studies show the influence of testosterone on aggression?
- Giammanco et al. (2005) showed experimental increased in testosterone are related to aggressive behaviour.
- Testosterone decrease leads to reduction in aggression in castration studies.
How does the Limbic system explanation exclude other possibilities?
- The Amygdala functions in tandem with the orbitofrontal cortex to maintain self-control and inhibit aggression.
- Coccaro et al. (2007) showed orbitofrontal cortex activity is reduced in patients with psychiatric disorders that feature aggression
= can’t explain by Limbic system solely.
What supporting evidence is there for the role of serotonin?
- Research shows increase in serotonin reduces levels of aggression.
- Berman et al. (2009) found that participants l given a serotonin enhancing drug gave fewer and less intense electric shocks to a confederate than people in a placebo.
A part from supporting evidence for the role of serotonin, give a further strength of the neural and hormonal mechanisms in aggression.
1) A plausible mechanism to explain testosterones effects.
- Mazur’s (1985) biosocial model of status (BMoS) suggests changes in testosterone levels following a loss of status in a competition should affect aggressive behaviour afterwards.
What evidence supports Mazur’s biosocial model of status?
- Mehta and Josephs (2006) found 73% of losers (whose testosterone levels rose afterwards) decided to rechallenge their opponent.
- But only 22% whose testosterone levels fell, decided to do so.
= support role of testosterone.
A part from the Limbic system explanation excluding other factors, give a further limitation of neural and hormonal mechanisms on aggression.
1) Neural/hormonal explanations research is correlational.
- Studies with humans impossible for ethical issues
- Issues with generalising with animals.
- Other factors overlooked, simply correlation between serotonin and aggression.
In terms of genetic factors in aggression, what twin study supports the role of genetics?
- Coccaro et al. (1997)
- Concordance rate = MZ of 50%, DZ of 19%
In terms of genetic factors in aggression, how do adoption studies support the role of genetics?
- If we find similarities in aggressive behaviour between an adopted child and biological parents.
- If similarities with adopted parents = environmental factors.
- Rhee + Waldman (2002) - meta-analysis of adoption studies found genetic influences accounted for 41% of the variance in aggression.
In terms of genetic factors in aggression, how does MAOA support the role of genetics? Describe it.
- It is an enzyme that cleans up neurotransmitters after a nerve impulse has been transmitted between neurons.
- Breaks down neurotransmitters to be recycled or excreted.
- A dysfunction in the MAOA gene may lead to abnormal activity of the MAOA enzyme –> levels of serotonin.
Why is the MAOA gene nicknamed the ‘warrior gene’ ? Can you explain the evidence that backs this up?
- ‘Warrior gene’ is a variant of the MAOA gene that leads to low MAOA activity –> aggressive behaviour.
- Brunner et al. (1993) studied 28 male members of a Dutch family repeatedly involved in impulsively aggressive criminal behaviour.
= had low levels of MAOA in their brain and low activity-version of the MAOA gene.
Who found that the most violent domestic abusers had the low-activity MAOA gene?
- Stuart et al. (2014) studied 97 men from a treatment programme for domestic abusers.
- Men with low-activity MAOA gene engaged in greatest psychological and physical aggression and inflicted worst injuries on partners.
Give 1 strength of genetic factors in aggression
1) MAOA explanation has support from animal studies.
- Genetic deletion allows researchers to ‘knockout’ single genes on mice so they could observe the effects on aggression.
- Godar et al. (2014) - showed MAOA knockout mice have increased brain serotonin and are hyper aggressive.
= when blocked by a drug –> non-aggressive.
Give 3 evaluative limitations of the genetic explanation in aggression.
1) Difficult to isolate genetic factors.
- Separate environment and genetic factors?
- McDermott et al. (2009) - participants with low-activity MAOA gene behaved aggressively in a lab-based task, but only when they were provoked.
2) Multiple genetic influences.
- Genetic effects quite small, but statistically significant.
- Stuart et al. (2014), along side low levels of MAOA, found low levels of serotonin transporter gene.
3) Findings depends on how aggression is measured.
- Methods differ between studies; include self-reports, observations etc.
- Rhee + Waldman’s study found genetic factors had a greater influence on aggression in self report studies than from parents.
= valid conclusions?
According to the ethological explanation of aggression, in what two ways is aggression beneficial to survival?
1) Reduces competition.
2) Establishes dominance hierarchies - aggression gives a special status.
What does ritualistic aggression mean?
- A series of aggressive behaviours carried out in a set order.
Explain what Lorenz (1966) found in to ritualistic aggression
- Observed intra-species aggression and found it was mainly ritualistic and rarely became physical.
- Intra-species aggression usually ends with an appeasement display
Adaptive = death at every counter would kill species off.
What is an IRM and what is it triggered by?
- Innate releasing mechanism; a built-in physiological process or structure.
- Identifies threatening stimuli in the environment.
What does the Innate Releasing Mechanism (IRM) trigger?
A fixed action pattern (FAP).
Explain what a FAP is.
- A pattern of behaviour triggered by an IRM.
- Lea (1984) says FAP is ritualistic and is universal among all species and follows an inevitable course which cannot be altered before it is completed.
How does Tinbergen (1951) back up the ethological explanation of aggression?
- Male sticklebacks.
- Another male entering a stickleback’s territory in mating season released a FAP.
- Red was the stimulus that triggered the IRM and in turn led to an aggressive IRM.
= No red –> no aggression.
= FAP did not change from one stimulus to another, always had to be completed.
What supporting evidence is there for the ethological explanation of aggression?
- Brunner et al. (1993) shows low activity of the MAOA gene is closely associated with aggressive behaviour
= innate biological basis? - Evidence for IRMs
; Activity in limbic system triggers aggressive behaviour.
= validity.
In terms of the ethological explanation of aggression, how are there cultural differences?
- Nisbett et al. (1996) found that when white males from the Southern US white males were insulted in a research situation, they were more likely than Northern US white males to become aggressive.
- Nisbett = a culture of honour, impulsive aggression was a learned social norm.
What evidence is there against ritualistic aggression?
- Goodall (2010) observed male chimps from one community systematically slaughter the members of another group.
- Even though the victims offered signs of appeasement and defencelessness, this didn’t inhibit aggression (as this explanation says it would).
A part from cultural differences and evidence against ritualistic aggression, give a further limitation against the ethological explanation of aggression.
1) Generalisations to human aggression.
- Lorenz didn’t study mammals such as primates and Tinbergen studied fish.
- Both generalised this behaviour to all human.
Why do men use mate retention strategies?
To avoid cuckoldry.
What is cuckoldry?
Raising offspring that are not their own.
In terms of the evolutionary explanation, why is cuckoldry a negative thing?
- Waste of resources contributing to the survival of a rival’s genes, leaving the father with fewer resources to invest in his own future offspring.
Identify the two mate retention strategies involving aggression that Wilson + Daly (1996) came up with.
1) Direct guarding - a man’s vigilance over a partner’s behaviour.
2) Negative inducements - e.g. threats of consequences for infidelity.
Who found that mate retention strategies are linked to physical violence?
- Wilson et al. (1995)
- Women who reported mate retention strategies in partners were twice as likely to suffer DV at their hands.
= 73% required medical attention, 53% feared for their lives.
How may bullying be an adaptive form of aggression?
Bullying = power imbalance in which a stronger individual uses aggression repeatedly against a weaker person.
- Evolutionary = increase chances of survival.
What did Volk et al. (2012) say about bullying in men?
- Suggests dominance, acquisition of resources, strength and ward off potential rivals.
= access to more females, minimal threat from males.
–> reproductive success.
In terms of the evolutionary explanation, what does bullying achieve with women?
- Secure partner’s fidelity.
- More inside a relationship than outside.
- -> continues to provide for offspring.
How does the evolutionary explanation explain gender differences?
- Males engage more often in aggressive acts.
- Campbell (1999) - aggression in females risk survival of offspring, so more adaptive use verbal aggression to retain a partner.
= validity?
How does the evolutionary explanation have real-life application?
- Rigby (2010) reviewed anti-bullying interventions
= despite interventions, bullying remained prevalent
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Fail to recognise bullies bully to gain an advanage
= why would they voluntarily give up power?
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Bullying somehow adaptive = help us understand alternative anti-bullying interventions.
Give 2 limitations of the evolutionary explanation of aggression
1) Cultural differences.
- This explanation = aggression present everywhere to increase survival chances.
- !Kung San in Kalahari discourage aggression, lose status and reputation if used.
- Yanomamo of Venezuela use aggression to gain status.
= aggressive behaviour not universal, learned?
2) Methodological issues with research evidence.
- Difficult to test hypotheses about evolution of behaviours; research = correlational.
- Even strong correlation does not mean cause and effect
= how valid?
In simple terms, what does the frustration-aggression hypothesis mean?
Frustration always leads to aggression.