Genetic Factors In Aggression

Question 1

What do twin studies show

Answer 1

Genetic factors account for about 42% of variance in aggressive behaviour

Question 2

What did Coccaro et al study

Answer 2

Adult male MZ and DZ twins for direct physical aggression

Question 3

What did Coccaro et al find

Answer 3

Concordance rates of 50% in MZ twins and 19% in DZ twins

Question 4

What were the results for verbal aggression

Answer 4

28% for MZ twins and 7% for DZ twins

Question 5

What did adoption studies show

Answer 5

Genetic factors account for about 41% of variance in aggressive behaviour

Question 6

What suggests that there are genetic influences operating

Answer 6

Similarities in aggressive behaviour between an adopted child and biological parents

Question 7

What did Rhee and Waldman do

Answer 7

Meta-analysed adoption studies and found genetic influences accounted for 41% of the variance in aggression

Question 8

What is linked to low serotonin

Answer 8

MAOA

Question 9

What is MAOA

Answer 9

An enzyme that mops up neurotransmitters after a nerve implied has been transmitted between neurons

Question 10

What does MAOA do

Answer 10

It breaks down the neurotransmitter into constituent chemicals to be recite cold or excreted

Question 11

What is determined by a MAOA drug?

Answer 11

The production of the enzyme

Question 12

What may a dysfunction in the operation of this gene lead to

Answer 12

Abnormal activity of the MAOA enzyme which affects levels of serotonin

Question 13

Name one variant of the MAOA gene

Answer 13

The warrior gene

Question 14

What is the warrior gene

Answer 14

A variant of the MAOA gene that leads to low MAOA activity in the brain and is associated with aggressive behaviour

Question 15

What did Brunner et al study

Answer 15

28 male members of a Dutch family repeatedly involved in impulsively aggressive violent criminal behaviours (e.g. rape, attempted murder)

Question 16

What did Brunner find

Answer 16

These men have both abnormally low levels of MAOA in the brains and the low activity version of the MAOA gene

Question 17

What did the most violent domestic abusers have

Answer 17

Low activity MAOA gene

Question 18

What did Stuart et al study?

Answer 18

97 man from a treatment program for domestic abuse who had inflicted a form of aggression called intimate partner violence

Question 19

What did Stuart et al find

Answer 19

Man with the low activity MAOA gene one the most violent perpetrators of IPV

Question 20

What did Fraxxetto et al find

Answer 20

An association between antisocial aggression and the low activity MAOA gene variant in adult males but only in those who experienced significant trauma during the first 15 years of life

Question 21

What was found about those who had not experienced trauma

Answer 21

They were not especially aggressive as adults even if they possessed the gene variant

Question 22

What can be concluded from Frazzetto et al’s findings

Answer 22

These findings together are strong evidence of a gene environment interaction (sometimes called diatheses stress)

Question 23

Name a disadvantage of genetic factors of aggression

Answer 23

Difficult to isolate - it’s difficult to separate genetic and environmental factors - someone with an aggression associated gene they only behave aggressively if the environmental conditions are suitable - proven to be challenging to establish exactly how influential genes are in aggressive behaviour