Genetic factors

Question 1

if aggression is influenced by genetics we would expect to find greater similarity in MZ twins - concordance rate 50% for MZ snd 19% for DZ (study on adult males) defined by direct physical assault

Answer 1

Coccaro et al

Question 2

meta analysis - adoption - direct aggression and antisocial behaviour - genetic variances account for about 41% of variance in aggression (correlate w twin studies)

Answer 2

Waldman and Rhee

Question 3

what is the role of the MAOA gene?

Answer 3

‘mop up’ neurotransmitters in brain after a nerve impulse has been transmitted from one to another - abnormal functioning affects serotonin levels

Question 4

studied 28 males of large Dutch family - repeatedly involved in violent criminal behaviour (rape, murder etc)- found that they had abnormally low levels of MAOA

Answer 4

Brunner et al

Question 5

higher levels of aggression can be associated with low activity Maoa variant but only when they had suffered from severe trauma

Answer 5

Frazzetto et al - this is sometimes called ‘diathesis stress’

Question 6

meta analysis - found no evidence of an association with any single gene and aggression - even hundreds interact (discussion)

Answer 6

Vassoss et al

Question 7

studied PPs w low and high activity variant of MAOA in a money-distributing game. whether to contribute money for good of the group. males w higher activity variant were more cooperative

Answer 7

Mertins et al