Biological: Genetic Explanation

Question 1

Who studied twins to evaluate the relationship between aggression and genes?

Answer 1

Coccaro 1997: Males 182 MZ and 118 DZ pairs. Genes contribute >40%, environment contributes 50% physical and 70% verbal aggression

Question 2

Give 2 methodological strenthgs of Coccaro’s 1997 study

Answer 2

Large sample, well operationalised

Question 3

Who studied adoptions to evaluate the relationship between aggression and genes?

Answer 3

Hutching and Medrick 1973: 14000 Denmark, sig. positive correlation between criminal violence convictions in bio parents (esp. fathers) and number of convictions of adopted sons

Question 4

Give one methodological strength and weakness of the Hutchings and Medrick 1973 study. What is the issue with stdying aggression in adopted children?

Answer 4

Large study, no girls though. Adopted children’s aggression due to circumstances of adoption instead (feeling abandoned)

Question 5

Who conducted a meta analysis into both adoption and twin studies on the relationship between aggression and genes?

Answer 5

Rhee and Walman 2002: 51 studies, 87000 Pps, operationalised: psychiatric diagnosis, deliquency, behavioural aggression. Genetic about 40%, little evidence of gender differences

Question 6

Which other meta analysis supports the Rhee and Waldman 2002 finding?

Answer 6

Mason and Frick 1994: 50% genetic influence, measured variance

Question 7

What can twin studies be criticised for?

Answer 7

Shared environment as well, so is gene influence really being measured, MZs also treated more similarly than DZs by society, DZs may share more than 50% of genes if parents chose each other because they were similar

Question 8

What is the general conclusion that can be drawn from the research into genes and aggression?

Answer 8

Approximate 40% gene influence and 60% environment, not solely genes: diathesis stress model

Question 9

What can adoption studies be criticised for?

Answer 9

adopted children’s aggression may be due to circumstances (abandonment feeling),

Question 10

Who found gender differences within aggression and genes? Why might other findings be more reliable?

Answer 10

Button 2004: stronger aggression genetic influence on girls but only 258 twin pairs (11-18yrs) whereas Rhee and Waldman found no difference from a meta analysis (much larger sample = more reliable result)

Question 11

What is another name for interactionism?

Answer 11

Holism

Question 12

What is passive interactionism? What is active interactionism?

Answer 12

P: environment provided by those who gave you your genes (parents). A: you choose your environment

Question 13

What does interactionism mean for aggression and genes?

Answer 13

Nature/nurture debate, if your genes (parents or you) chose your environment does the environment really influence your aggression more than your genes?

Question 14

What is MAOA? How is this related to the genetic explanation?

Answer 14

Enzyme that breaks down noradrenalin, serotonin and dopamine. If gene responsible for producing MAOA is defective, these are not broken down leaving excess amounts in the body

Question 15

What do noradrenalin, serotonin and dopamine do to the body in relation to aggression?

Answer 15

N: raises BP and activates the flight or fight response. S and D imbalances are common in aggressive patients

Question 16

Who conducted a study into the defective MAOA gene?

Answer 16

Caspi 2002: effect of MAOA not sig between normal and mutant, maltreatment during childhood sig affect, combined affect of maltreatment and mutant MAOA sig affect on aggression

Question 17

What did the results of Caspi 2002 show an example?

Answer 17

Interaction

Question 18

Who conducted a study into a family genetic defect causing aggression?

Answer 18

Brunner 1993: Netherlands, male violent history, genetic defect on X (inhibits enzyme which regulates aggressive behaviour) near MAOA gene, excess neurotransmitters found in urine -predispose to violence when under stress

Question 19

What is an issue with the results of Brunner’s 1993 study?

Answer 19

Unlikely direct causal link between 1 gene and specific behaviour

Question 20

What are the positive implications of research in to the MAOA gene? IDA

Answer 20

Studies into molecular genetic pathways are leading to production of pharmaceutical to fix these problems and change aggressive behaviour