biological explanations

Question 1

twin studies - Lange 1930

Answer 1

studied 13 MZ twins and 17 DZ twins where one of the twins of each pair spent time in prison
- Lange found that both twins in 10 of the 13 MZ twin pairs were known criminals, compared with only 2 of the 17 DZ twin pairs

Question 2

Christiansen 1977

Answer 2

examined over 3,500 twin pairs in Denmark and identified concordance rates of criminal behaviour.

• 35% of male MZ twins compared to 13% of male DZ twins
• 21% of female MZ twins compared to 8% of female DZ twins
• suggesting behaviour and underlying predisposing traits are inherited

However, the concordance rates are not very high and leave plenty of room for non-genetic environmental factors

Question 3

adoption studies - crowe 1972

Answer 3

found that adopted children who had a biological parent with a criminal record had a 50% greater risk of a criminal record by the age of 18.

• But adopted children whose mothers didn’t have a criminal record only had a 5% risk.

Question 4

neural explanations - ANTISOCIAL PERSONALITY DISORDER

Answer 4

Raine et al (2000) found an 11% reduction in the volume of grey matter in the prefrontal cortex of people with APD compared to controls → this is part of the brain that regulates emotional behaviour

Recent research suggests that criminals with APD can experience empathy but they do so differently to the rest of us.
Keysers et al (2001) found that only when criminals were asked to emphasise did their empathy reaction activate. This suggests that mirror neurons (empathy) may not always be turned on.

Question 5

what is an antisocial personality disorder

Answer 5

APD is associated with the lack of empathy, impulsive, reduced emotional response and is suffered by many convicted criminals

Question 6

diathesis-stress model

Answer 6

A tendency to criminal behaviour may come about through a combination of:
● Genetic predisposition
● A psychological stress-trigger such as criminal role models or a dysfunctional upbringing

Question 7

Tiihonen et al 2014

Answer 7

Tiihonen et al 2014 - genetic analysis of 800 offenders
Found that 2 specific candidate genes were associated with violent crime
Abnormalities of 2 genes
Maoa = controls dopamine and serotonin in the brain and is linked to violent crime
CDH13 = substance abuse and ADHD
5% to 10% of all several violent crime in finland is attributable to the MAOA and CDH13 genotypes