Forensic Psychology : L4 Genetic & Neural Explanations

Question 1

Genetic Explanations

Answer 1

Suggests offenders inherited a genes that determines them to commit a crime

Question 2

Support study for Genetic Explanation

Answer 2

Lange (1930) investigated 13 monozygotic twins and 17 dizygotic twins. At least one of the twins in each pair had served time in prison. 10 of the 13 pairs of monozygotic twins had both spent time in prison, whereas only 2 of the 17 pairs of dizygotic twins had both spent time in prison.

Question 3

Polygenic

Answer 3

No one single gene is responsible for offending

Question 4

Candidate Genes

Answer 4

Many genes might be responsible for causing criminal behaviour

Question 5

Genetic analysis study of genes associated with violent crime

Answer 5

• Tilhonen et al. (2014) studied over 900 Finnish offenders.
• Abnormal Genes: MAOA and CDH13 genes were found to be associated with violent crime.
• MAOA Gene: Controls dopamine and serotonin in the brain, linked to aggressive behaviour.
• CDH13 Gene: Linked to substance abuse and attention deficit disorder.
• High-Risk Combination: Individuals with both genes were 13 times more likely to have a history of violent behaviour.

Question 6

Diathesis-stress model

Answer 6

Genetics influence criminal behaviour but this is at moderated by the effects of the environment (raised in a dysfunctional family)

Question 7

Neural Explanations

Answer 7

Suggests that there may be neural differences in the brain of criminals compared with non-criminals

Question 8

APD (anti-social personality disorder)

Answer 8

• Associated with reduced emotional responses and a lack of empathy, a condition that characterises many convicted criminals
• Reduced Activity: Anti-social individuals have reduced activity in the pre-frontal cortex (PFC), which regulates emotional behaviour.
• Grey Matter Reduction: APD individuals have an 11% reduction in PFC grey matter volume compared to controls (Raine et al., 2000).
• Neural switch to have empathy needs to be switched on

Question 9

(-) Evaluation

Answer 9

• Concordance rates in MZ twins are not high and leave plenty of room for nongenetic environmental factors. Concordance rates may be due to shared learning experiences rather than genetics.
• Brain scanning studies (such as Raine et al., 2000) cannot conclude whether these abnormalities are genetic or signs of early abuse.
• The term ‘offending behaviour’ is too vague. Some specific forms of crime may be more biological than others e.g. physical aggression.
• Both explanations are an example of biological reductionism. Criminality is complex and explanations that reduce offending behaviour to a gene or imbalanced neurotransmitter may be inappropriate and overly simplistic. Twin studies never show 100% concordance rates in monozygotic twins, so genetics cannot be the only explanation for criminal behaviour.
• Both explanations are biological deterministic. This presents us with a dilemma for our legal system. If someone has a criminal gene they cannot have personal and moral responsibility for their crime. If this is the case it would be unethical to punish someone who does not have free will.