Biological - Genetic And Neural

Question 1

What are the genetic explanations for offending

Answer 1

1. Twin + adoption studies
2. Candidate genes
3. Diathesis stress model

Question 2

Twin + adoption studies

Answer 2

Christiansen 1977
• studied 3500+ twin pairs in Denmark
• found a concordance for offender behaviour 37% for MZ males (lower for females)
• supporting genetic component in offending

Crowe 1972
• found adopted children who had biological mother w a criminal record had 50% risk of having a criminal record by 18
• adopted children whose mother didn’t have a criminal record only 5% risk

Question 3

Candidate genes

Answer 3

• Tiihonen et al suggested 2 genes are associated with violent crime after analysis of 800 offenders
• MAOA gene regulates serotonin + linked to aggressive behaviour
• CDH-13 gene linked to substance abuse + adhd
• found 5-10% of all severe violent crime in Finland is attributable to MAOA + CDH-13 genotypes

Question 4

Explain diathesis stress model

Answer 4

• if genes influence offending, the likely to be at least partly moderated by environmental factors

Suggests a tendency to offending behaviour is due to :
- genetic predisposition
- biological/psychological stressor/trigger

Question 5

Limitation genetic explanation
- issues w twin evidence

Answer 5

• limitation of twin studies is the assumption of equal environments
• it’s assumed twins are brought up in the same environment
• environment assumptions made more to MZ look more identical and ppl treat them similarly compared to DZ

Question 6

Strength of genetic explanation
- support for diathesis stress

Answer 6

• study of 13000 danish adoptees
• when neither biological/ adoptive parents had conviction, adoptees that did was 13.5%
• biological parent w conviction figure rose to 20%
• biological & adoptive parents w conviction figure rose to 24.5%

Question 7

What are the neural explanations for offending behaviour

Answer 7

1. Antisocial personality disorder
2. Less activity in the prefrontal cortex
3. Mirror neurons (empathy)

Question 8

Antisocial personality disorder

Answer 8

Is associated w lack of empathy + reduced emotional responses. Many convicted offenders have a diagnosis of APD

Question 9

Prefrontal cortex

Answer 9

• Many studies of APD report that there is reduced activity in the prefrontal cortex
• this is the part of the brain that regulates behaviour
• Raine found 11% reduction in the volume of grey matter in the prefrontal cortex compared to people with APD

Question 10

Mirror neurons

Answer 10

• research suggest offenders w APD experience empathy more sporadically than the norm
• found that only when asked to empathise offenders activated that part of their brain
• suggest there may be a neural switch

Question 11

Strength of neural explanation
- brain evidence

Answer 11

• link between the frontal lobe and crime
• people with damage in the frontal lobe show impulsive behaviour, emotional instability & inability to learn from mistakes
• associated with planning

Question 12

Limitation of neural explanations
- intervening variables

Answer 12

• other factors may contribute to APD

Farrington et al
• studied men who scored high for psychopathy
• individuals had experienced various risk in childhood
• reduced activity in the frontal lobe may be from trauma