genetic factors in aggression

Question 1

how often does the chromosome XYY occur

Answer 1

early psychologists investigating aggression believed the genetic cause of aggression could lie in the Y chromosome. Examined individuals with XYY genotype. occurs every 1 in 1000 males

Question 2

what were people with XXY referred as and why

Answer 2

super males
because they possessed two male Y chromosomes

Question 3

evidence for extra Y chromosome

Answer 3

study on males in criminally insane hospitals. 28% of patients had extra Y chromosome compared with 0.1% of the general population

Question 4

research to undermine Y chromosome in aggression

Answer 4

study on males with XYY genotype found that it can cause increase in height but not an increase in aggression

Question 5

what do genes affect

Answer 5

genes alone do not control aggression but they affect the production of hormones and neurotransmitters which in turn affect aggression.

Question 6

what is the gene identified to carry the aggression trait

Answer 6

the MAOA gene

Question 7

what is the MAOA gene responsible for

Answer 7

the production of the protein monoamine oxidase, which allows the breakdown of noradrenaline, serotonin and dopamine

Question 8

what happens if there is a dysfunction in the MAOA gene?

Answer 8

results in the neurotransmitters not being broken down in the body. If adrenaline isnt metabolised then we end up with too much. This can cause hypersensitivity in the fight or flight response and individuals may overreact to an external stimulus and individuals may perceive a threat where one does not exist

Question 9

what happens if dopamine is not broken down

Answer 9

too much dopamine and increased or excessive levels of dopamine are linked to aggressive behaviour

Question 10

research to support the role of genetics in aggression (twin study)

Answer 10

MZ and DZ twins examined for the concordance of criminal behaviour. MZ twins had a 50% concordance whereas DZ twins had 19% concordance.

Question 11

research to support the role of MAOA gene

Answer 11

study on Dutch family. 5 male members possessed shortened version of MAOA gene, so they had low levels of MAOA enzyme and not able to break down all the neurotransmitters. They were aggressive and some been in prison for attempted rape and assault.

Question 12

research evidence to support the role of genotype in maltreated children

Answer 12

Caspi et al. investigated why some children who are maltreated develop antisocial behaviour.
442 male children followed from birth to adulthood
85% of males having low activity MAOA gene genotype who were maltreated developed antisocial behaviour
(they were 3x more likely to be aggressive)
Males with high MAOA activity did not have elevated antisocial scores even when they had experienced childhood maltreatment.
- Provides evidence that genotypes can moderate children’s sensitivity to environmental insults

Question 13

Evaluation of genetics and aggression

Answer 13

1. COMPARATIVE - animals do not fully apply to humans
2. REDUCTIONIST - only looking at biological and ignoring social psychology issues
3. DETERMINISTIC - argues our aggression is predisposed and ignored human free will, can have implications as people blame their aggressive actions on biology