genetic factors

Question 1

how many genes do MZ twins share

Answer 1

100%

Question 1

what do twin studies suggest

Answer 1

heritability accounts for 50% of aggressive behaviour

Question 2

how many genes do DZ twins share

Answer 2

50%

Question 3

what did researchers find in concordance rates

Answer 3

50% MZ twins
19% DZ twins

Question 4

in adoption studies what suggests that genetic influences are operating

Answer 4

when there are similarities in aggr beh between adopted child and their bio parents

Question 5

in adoption studies what suggests that environmental influences are operating

Answer 5

similarities between adopted child and their adoptive parents

Question 6

what did Rhee and Waldman do

Answer 6

meta analysis of adoption studies of aggressive anti social behaviour

Question 7

what did Rhee and Waldman find

Answer 7

genetic influences accounted for 41% of the variance in aggression, so in line with twin studies

Question 8

what does the MAOA gene control

Answer 8

the production of enzyme MAO-A which regulates serotonin (serotonin thought to play important role in impulsive aggression)

Question 9

what does a low activity variant MAOA gene cause

Answer 9

low activity of MAO-A enzyme which is linked to high levels of aggressive behaviour

Question 10

MAOA gene, when is it triggered

Answer 10

gene is inherited, but activated by an environmental experience

Question 11

nature v nurture

Answer 11

both
nature- evidence shows genes act as a direct cause of aggression
nurture- environmental factors also play a role eg childhood trauma

Question 12

Caspi et al (nature v nurture)

Answer 12

MAOA gene had not effect on its own, only in circumstances of abuse

Question 13

strength of genetic factors

Answer 13

research support shows that the low activity variant of the MAOA-L gene is associated w greater aggression

Question 14

research support study

Answer 14

Martins et al

Question 15

Martins et al findings

Answer 15

men w high activity variant of MAOA gene were more cooperative and made fewer aggressive moves than the low activity ppt.

this supports relationship between MAOA gene activity and aggression

Question 16

limitation of Martins study

Answer 16

showed non-genetic factors were also crucial, knowledge of social norm partly determined their aggression

= genes influenced by environmental factors

Question 17

limitation of genetic factors

Answer 17

problems w twin studies

Question 18

problems with twin studies

Answer 18

they may lack validity

DZ twins may not share their environment to the same extent MZ twins share theirs, MZ twins are treated more similarly

suggests concordance rates are inflated, perhaps genetic influences may not be as great as twin studies suggest