Genetic Explanations

Question 1

Genetic Explanation of aggression

Answer 1

-suggests that aggressive behaviours are inherited

Question 2

Twin Studies

Answer 2

-If aggression is innate, we should see increased aggression monozygotic (MZ) twins who share 100% of their genome, compared to DZ twins who share 50%

Question 3

Twin Studies AO3 strength

Answer 3

-Researchers compared MZ and DZ vietnamese twins, finding that genetic differences did account for differences in aggression e.g 47% of direct assaults

Question 4

Why are family studies/adoption studies used

Answer 4

-Family studies are used to show that the closer the biological relationship, the higher the concordance rate of aggression
-However, it is difficult to test for nurture influences as genetically closer family members are more likely to share environments
-Adoption studies aim to fix this issue

Question 5

A03 Danish Criminality study (strength of genetic explanation)

Answer 5

-Criminality is often associated with aggression
-Researchers found that 10.5% of Danish adoptees with non-criminal biological fathers were criminals, compared to 21.4% of those with criminal biological fathers

Question 6

MAOA-L (Warrior Gene)

Answer 6

MAOA is an enzyme that breaks down the neurotransmitter serotonin in the brain
-The low- activity variant (MAOA-L) is associated with aggression
-This variation results in the low production of the MAOA enzyme, causing high levels of serotonin in the brain

Question 7

Diathesis stress model of aggression

Answer 7

This “Warrior gene” has been found in 1/3 of Western men and 60% in some communities
-Clearly, not all of these men are aggressive
-It seems that these aggressive behaviours only occur if these men have a history of child abuse
-This is the Diathesis (gene) stress (abuse) model of aggression

Question 8

A03 Strength for genetic explanations of aggression (Netherlands aggression extended family study)

Answer 8

Brunner (1993) conducted a case study on an extended family
-The males had a history of impulsive aggression and attempted rape
-The males in the family were found to have the low activity MAOA gene
-This suggests that extreme aggressive behaviour does have some genetic origin