Aggression - Genetics

Question 1

What are four AO1 factors which you should look at in genetics

Answer 1

Twin studies

Adoption studies

Research on genetics factors

MAOA gene

Question 2

Explain twin studies as a genetic factoring a study

Answer 2

Coccaro et al 1997 - found that nearly 50% of the variance in direct aggressive behaviour could be attributed to genetic factors

Question 3

What type of twins are identical

Answer 3

Monozygotic

Question 4

What type of twins are non-identical

Answer 4

Dizygotic (50%)

Question 5

Explain adoption studies

Answer 5

untangle relative contributions of environment and hereditary in aggression

Question 6

What happens if the correlation positive is in in adoptive children and their biological parents

Answer 6

if the correlation is positive between aggressive behaviour and biological parents then genetic factor is applied

Question 7

What happens if the correlation is positive between adoptees aggressive behaviour and their rearing family

Answer 7

then an environmental factor is applied

Question 8

explain an adoption study

Answer 8

14,000 adoption in Denmark found that a significant number of adopted boys with criminal convictions had biological parents with criminal convections providing evidence for the genetic effect

Question 9

Give a 1997 study on genetic factors in aggression

Answer 9

Miles and Carey

Question 10

Explain a 1997 study on genetic factors in aggression

Answer 10

meta analysis of 24 twin and adoption studies that showed a genetic basis.
The results suggest a strong genetic factor that could account for as much as 50% of the variance in aggression

Question 11

who did this - meta analysis of 24 twin and adoption studies that showed a genetic basis.
The results suggest a strong genetic factor that could account for as much as 50% of the variance in aggression

Answer 11

Miles and Carey 1997

Question 12

What was another important factor in in Miles and Carey 1997 study

Answer 12

Age as with both genes and environment being influential in determining aggression in youth but at later ages it way mainly the influence of genes that determined aggression

Question 13

What is another study on genetic factors in 2002

Answer 13

Rhee and Waldman

Question 14

What did Rhee and Waldman do?

Answer 14

combined the results of 51 twin and adoptions studies finding that aggressive behaviour was largely due to genetics

Question 15

Counter argument for Rhee and Waldman

Answer 15

the same as Miles and Carey other factors such as age suggest that other factors effect the expression of aggressive behaviour

Question 16

What is MAOA

Answer 16

Monoamine oxidase is an enzyme that among other things regulates the metabolism of serotonin in the brain

Question 17

What is the role of MAOA

Answer 17

regulates the metabolism of serotonin in the brained low levels are associate with impulsive behaviour

Question 18

explain a study on the role of MAOA

Answer 18

A 1980S study on a dutch family found males behaved aggressively and a majority had been involved in serious crimes of violence these males were found to have abnormally low levels of MAOA in their bodies and a defect in this gene was later identified

Question 19

Explain MAOA-H + MAOA-L using a study

Answer 19

Caspi et al 2002 on 500 male kids they discovered a variant of the gene associated with high levels of MAOA-H and a variant associated with low levels of MAOA-L

Question 20

Explain the variants in Caspi’s study in 2002

Answer 20

those with the MAOA-L variant were more likely to grow up showing anti-social behaviour but ONLY is they had been maltreated as a child

Children with the MAOA-H variant who were maltreated and those who were MAOA-L variant who were not maltreated did not display anti-social behaviour

Question 21

Explain the warrior gene with a study as well

Answer 21

MAOA-L is more frequent in populations with history of warfare with 2/3 having MAOA-L gene

McDermott 2009 found (L) displayed higher levels of aggression when provoked than did (H) subjects

Question 22

What are the problems of sampling of genetic research

Answer 22

these studies have focused on individuals convicted of violent crime however they represent a minority of those regularly involving with violent crimes as some are not convicted

secondly violent based on court convictions however someone may be classed as violent but only committed one crime and had a lifetime free of crime, this may explain why studies have found little evidence of heritability

Question 23

Explain difficulties determining the role of genetic factors

Answer 23

it is hard to establish genetic contributions to aggressive behaviour because: more than one gene contributed to a behaviour

environmental influences on aggressive behaviour

Genetic factors may affect which environmental factors have an influence and vice versa

Question 24

What are the problems of assessing aggression

Answer 24

studies such as Miles and Carey used self-report and found genetic factors explained a large proportion of the variance in aggressive behaviour however studies using observation showed less genetic contribution and greater environmental influences

this makes it hard to assess the relative contributions of genetic and environmental factors in aggression

Question 25

What is the evidence for the influence of the MAOA gene

Answer 25

Tihnonen 2015

Question 26

What did Tihnonen 2015 do and find

Answer 26

studied Finnish prisoners revealing that the MAOA low-activity genotype in combination with another gene was associated with extremely violent behaviour no evidence for either of these genes among non-violent people indicating that this combination of genes was specific for violent offending only

Question 27

What do critics say about Tihnonen 2015 findings

Answer 27

although these genes ay make it harder for some people to control urges they do not predetermine violent behaviour

Question 28

How may the MAOA gene explain gender differences in aggressive behaviour

Answer 28

Niehoff 2014 shows that the uneven rates of violence between male and female may be a consequence of the differential genetic vunerablitlity that makes males and female have to the MAOA gene

Question 29

Explain Niehoff 2014 further

Answer 29

MAOA is linked to X chromosome which women have two and men one. When men inherit a X-linked gene from mum they are more likely to be affected as women have a 2nd X with a normal gene for MAOA that prevents expression of abnormal version of MAOA gene this could explain why males typically show more aggressive behaviour than females