genetic factors

Question 1

what types of studies show a genetic basis to aggression

Answer 1

1. twin studies = heritability accounts for approx. 50% of variance in aggressive behaviour
2. rhee and waldman = adoption meta-analysis looking at direct aggression and antisocial behaviour
   - found genetic influence accounted for 41% of variance in aggression

Question 2

link between MAOA gene and aggression

Answer 2

MAOA gene = control enzyme MAO-A production, which regulates serotonin

• low activity variant of MAOA = reduced activity of MAO-A = linked to higher aggression levels

Question 3

what are gene-environment interactions

Answer 3

genes = do not function in isolation

frazzeto et al = association between low activity MAOA and higher levels of antisocial aggression only found in males who has experienced significant trauma in first 15 yrs of life

• no trauma = not particularly high adult aggression even if possessed low activity MAOA

Question 4

strength of genetic basis to aggression

Answer 4

research support
= for role of MAOA in aggression
- frazzeto et al
mertins et al = money distributing game using low activity and high activity MAOA variant male pps
= men with high activity variant more cooperative + made fewer aggressive moves than low activity pps

= support relationship between MAOA activity and aggression

Question 5

weakness of genetic basis to aggression

Answer 5

reductionist and deterministic
- isolating MAOA gene has helped improve understanding on how genes can impact aggression
- however many genes involved in aggression levels
= cannot say MAOA causes aggression as simply not true
= also suggests choosing to respond aggressively is not our own choice but rather determined by genes

• to understand aggressive behaviour need to look at plethora of factors due its complexity

Question 6

further weakness of genetic basis to aggression

Answer 6

twin study problems
= lack validity

equal environment assumption = DZ twins share environment to same extent as MZ twins
- not the case, MZ twins tend to be treated more similarly than DZ

= concordance rates from twin studies may be inflated = genetic influence overexaggerated