Aggression - Biological Explanations of Aggression Flashcards
What does MZ and DZ twins stand for?
Monozygotic (identical)
Dizygotic (non-identical)
In which type of twin is aggressive behaviour highly correlated?
MZ twins
What are the study associated with twin studies of aggression?
McGuffin and Gottesman (1985)
What happened in McGuffin and Gottesman (1985)?
Concordance rate of 87% for juvenile aggressive and antisocial behaviour in MZ twins, compared to 72% for DZ twins.
What do the results of McGuffin and Gottesman (1985) suggest?
There is a significant genetic contribution to aggressive behaviour.
What is the Warrior Gene?
Gene responsible for producing enzyme monoamine oxidase A (MAOA) may be associated with aggressive behaviour (Warrior Gene). MAOA’s job to break down neurotransmitters in brain. When gene not functioning correctly, excess levels of neurotransmitters may lead to aggression.
What is the case study associated with the Warrior Gene?
Jim Fallon
What happened with Jim Fallon?
Has same brain and genetics of serial killer but not a killer, however lacks empathy.
What brain damage do serial killers sometimes have?
Orbital cortex, temporal lobe, amygdala.
What are two problems to do with twin studies?
Assume MZ and DZ twins experience the same upbringing, may not as parents/teachers make an effort to differentiate twins depending upon personalities.
Concordance rates are below 100%, means genetic influence is only part of the explanation.
What are two studies associated with the influence of genes on aggression?
Lagerspetz (1979)
Brunner et al (1993)
What happened in Lagerspetz (1979)?
Bred 25 gens of mice, 2 most aggressive and 2 least aggressive. Lead to one groups being super-aggressive and the other very docile.
What do the results of Lagerspetz (1979) show?
There is, at least in animals, a genetic component to aggressive behaviour.
What is a positive and negative of animal research in relation to Lagerspetz (1979) study?
Positive - Quality of Research, bred 25 generations of mice, large participant size. Clear variables and ruled out social differences.
Negative - Degree of animal suffering, do not show outward signs of suffering. Being aggressive may reduce chances to mate and pass on their genes.
What happened in Brunner et al (1993)?
Family with men having history of violence. Violent men suffer a genetic defect on X chromosome, cripples enzyme regulating aggressive behaviour. Not found in non-violent men of family. Tested urine, found excess levels of neurotransmitters, may have predisposed men to violence.
What positive implications does research into aggressive have?
Offender treatment and rehabilitation - Can predict if a person will be aggressive then they can get help or anger management before they murder or hurt people.
Why is the role of genes in relation to aggression socially sensitive?
Blames parents for child’s aggressive behaviour, stating 2 aggressive individuals are likely to have an aggressive child.
Why is the role of genes in relation to aggression Deterministic?
People still have a moral sense of what is right and wrong, free will. Labelling people as aggressive means they have an excuse for their aggressive behaviour.
What are neurotransmitters?
Chemicals that allow impulses to travel between neurons.
What neurotransmitters play a part in aggression? High or low levels?
Low levels of serotonin
High levels of dopamine
How is serotonin associated with aggression?
Normal levels - calming effect on brain. Low levels - inhibitory effect removed, leading to less control of behaviour.
What study is associated with serotonin and aggression?
Mann et al (1990)
What happened in Mann et al (1990)?
Gave dexfenfluramine to 35 P’s, depletes serotonin levels, used questionnaires to access hostitli8ty and aggression levels, found hostility and aggression levels to increase in males.
Evaluate the study of Mann et al (1990).
Aggression didn’t increase in woman, socially desirable answers, less likely to admit to undesirable behaviour. Questionnaires only gather info P’s are willing to share, may not be same as actual behaviour. Leads to lack of validity in data.
How is dopamine associated with aggression?
Increases in dopamine activity = increases in aggressive behaviour.
What study is associated with dopamine and aggression?
Ferrari et al (2003)
What happened in Ferrari et al (2003)?
Allowed rat to fight for 10 days, on 11th day didn’t allow, found serotonin and dopamine levels increased in anticipation of a fight.
What do the results of Ferrari et al (2003) show?
Shows experience of aggression changes the animals brain chemistry.
Evaluate the ethics of Ferrari et al (2003) in relation to animals.
Protection through legislation -Strict laws and codes of conduct that protect animals used in research.
Animal rights - Have right by virtue of their ‘inherent value’, includes the right to be respected and not harmed.
What hormone is associated with aggressive behaviour?
Testosterone
How is testosterone associated with aggressive behaviour?
Males more aggressive than females, may be due to 10 times more testosterone, levels escalate at puberty 15-25, age group most likely to commit violent crimes.
What study is associated with testosterone and aggressive behaviour?
Dabbs et al (1995)
What happened in Dabbs et al (1995)?
Studied testosterone levels of inmates, those who had committed violent and non-violent crimes. Found higher testosterone levels in more violent crimes.
What can be concluded from Dabbs et al (1995)’s results?
Positive correlation between violent crimes and higher levels of testosterone.
Evaluate Dabbs et al (1995).
If testosterone were major force behind aggression, we’d expect all females to be docile and men aggressive. Other factors must be involved.
Why is correlational research a problem in relation to Dabbs et al (1995)?
Cannot be sure if high testosterone levels are causing or aggression or if aggression is causing high testosterone levels or if another factor is causing both.
What are the IDAs relevant to biological causes of aggression?
Nature v Nurture
Socially Sensitive Research
Why are biological causes of aggression part of the Nature v Nurture debate?
Brunner et al (1993) shows there is a genetic element to aggression. Significant number of males in the family are aggression. But if the was all due to genetics, we’d expect a;; od the males to have aggression problems.
Why are biological causes of aggression socially sensitive?
Could be used to explain away unacceptable behaviour, Mann et al (1990) implies neurotransmitters are the cause of aggressive behaviour. Therefore individuals could justify attacks by claiming that their biology made them do it.
