Genetic factors in agg

Question 1

name 4 genetic factors

Answer 1

-twin studies
-adoption studies
-MAOA gene
-gene environment interactions

Question 2

what have twin studies suggested?

Answer 2

genetic factors account for 50% of variance in agg

Question 3

who studied men to support twin studies?

Answer 3

● Twin studies have suggested that genetic factors accounts for
50% of the variance in aggressive behaviour
● Coccaro et al - studied men who were either MZ or DZ twins -
expect to see similarities in aggressive behaviour in MZ twins
and this was the case
● Researchers found concordance rates 50% MZ and 19% for
DZ twins (physical assault)
● Verbal aggression 28% MZ and 7% DZ

Question 4

Adoption studies

Answer 4

similarities in agg behaviour between adopted child + bio parents = genetic influences
-similarities between adopted child + parents = enviroment influenced r operating

Question 5

rhee + waldman study

Answer 5

meta analysis of adoption studies of agg + anti-social beh
found genetic influences accounted for 41% of variance in aggHa

Question 6

Hatchings + Mednick

Answer 6

-compared14000 adoptions in Denmark
-criminal adopted boys
-found sig no had biological parents who were convicted criminals
suggests genetic link rather than enviromental

Question 7

Define the MAOA gene

Answer 7

-regulates serotonin levels = impacts impulsive agg
-low variant = high levels of agg
-high variant = low levels of agg beh

Question 8

Lea + Chambers

Answer 8

MAOA variant possessed by 56% of new Zealand men
rep for being warriors - compared to caucasian men = 34%

Question 9

Bruner et al

Answer 9

-studied 28 men from large Dutch fam who were involved in repeatedly in agg criminal behaviour - men had abnormally low levels of MAOA

Question 10

Gene enviroment interactions

Answer 10

crucial influences on agg behaviour but don’t work in isolation

Question 11

What is related to adult agg when linked to early trauma?

Answer 11

MAOA gene

Question 12

Frazzetto et al

Answer 12

-found an association between higher levels of antisocial agg and MAOA gene
-but only if people had experienced sig trauma within first 15 years of life
-those who didn’t experience trauma didn’t have High levels of agg beh even tho they had low MAOA gene
-evidence for diathesis stress model

Question 13

abusive enviroment + low maoa + what?

Answer 13

aggresive beh

Question 14

strength of genetic factors of agg (rs)

Answer 14

-research support
-support for MAOA gene
-vanessa mertins et al - men with different variants played a money game
-men with higher variant showed lower agg beh
-men with low variant showed more agg beh

Question 15

counter of rs

Answer 15

mertins study also showed non-genetic factors
-those with low gene behaved less agg when saw others acting same
social influence on them
-genes r influenced by enviromental factors

Question 16

limitation of genetic factors (twins)

Answer 16

-twin studies may lack validity
-twins share same environment
-but one aspect of environment is way their treated
-mz treated more similarly
-dz treated differently
-means concordance rates r inflated and genetic influences on agg may not be as great as twin studies imply

Question 17

Limitation of gen factors

Answer 17

-nature/nurture
-evidence all points to genes as cause of agg
-maoa, twins and adoptions/ animal studies
-however also evidence that environment factors r important
-criticism of twin studies support this
-early childhood trauma also plays a role
-environmental factors affect weather nor not genes r expressed