Forensics- Biological Explanations: Genetics And Neural Explanations

Question 1

Genetics -

Answer 1

Genes consist of DNA strands. DNA produces ‘instructions’ for general physical features of an organism (such as eye colour, height) and also specific physical features (such as neurotransmitter levels and size of brain structures). These may impact on psychological features (such as intelligence and mental disorder). Genes are transmitted from parents to offspring, i.e. inherited.

Question 2

Neural explanation -

Answer 2

Any explanation of behaviour (and its disorders) in terms of (dys)functions of the brain and nervous system. This includes the activity of brain structures such as the hypothalamus, and neurotransmitters such as serotonin and dopamine.

Question 3

Genetic Explanations for Crime

What do genetic explanations for crime suggest?

Answer 3

Genetic explanations propose that certain individuals inherit genes, or combinations of genes, that predispose them to commit crimes.

Question 4

Twin Studies

What do twin studies reveal about genetic influences on crime?

Answer 4

•Lange (1930):
•Studied 13 identical (MZ) and 17 non-identical (DZ) twins where one twin had served prison time.
•Found that 10 MZ twins but only 2 DZ twins had co-twins who were also in prison.
•Concluded that genetic factors play a significant role in offending behavior.

Question 5

Adoption Studies

What did adoption studies uncover about genetics and crime?

Answer 5

•Crowe (1972):
•Adopted children with a biological parent who had a criminal record had a 50% risk of a criminal record by age 18.
•Adopted children without a criminal biological parent had only a 5% risk.

Question 6

Candidate Genes

Which genes are linked to violent crime?

Answer 6

•Tihonen et al. (2014):
•Genetic analysis of 900 offenders identified abnormalities in:
•MAOA gene: Regulates dopamine and serotonin, linked to aggressive behavior.
•CDH13 gene: Linked to substance abuse and ADHD.
•Individuals with both abnormalities were 13 times more likely to have a history of violent behavior.

Note: Research on candidate genes is in its early stages and has yet to be replicated.

Question 7

Diathesis-Stress Model

How does the diathesis-stress model apply to crime?

Answer 7

This model suggests that genetic predispositions may combine with environmental or psychological triggers, such as a dysfunctional upbringing or exposure to criminal role models, to influence criminal behavior.

Question 8

Neural Explanations for Crime

What are neural differences between criminals and non-criminals?

Answer 8

Much of the research focuses on individuals with antisocial personality disorder (APD):
•Associated with reduced emotional responses and lack of empathy, traits common in many convicted criminals.

Question 9

Prefrontal Cortex

•	Raine et al.:

Answer 9

•Brain imaging studies show reduced activity in the prefrontal cortex, responsible for regulating emotional behavior.
•Found an 11% reduction in grey matter volume in individuals with APD compared to controls.

Question 10

Mirror Neurons

Answer 10

•Keysers et al. (2011):
•Found that individuals with APD could activate empathy (via mirror neurons) when explicitly asked, suggesting they have a neural ‘switch’ for empathy, unlike typical brains where empathy is continuously active

Question 11

Evaluation

Problems with Twin Studies

Answer 11

1. Early studies (e.g., Lange) were poorly controlled and lacked DNA testing for zygosity, instead relying on physical appearance.
   
   2. Small sample sizes reduce generalizability.
   3. Shared environments among twins confound genetic influences with learned behaviors.

Question 12

Evaluation

Support for the Diathesis-Stress Model

Answer 12

•Mednick et al. (1984):
•Studied over 13,000 Danish adoptees, defining criminality as having at least one court conviction.
•13.5% of adoptees had convictions when neither biological nor adoptive parents had criminal records.
•20% when one biological parent had convictions.
•24.5% when both biological and adoptive parents had convictions.
•This suggests genetic inheritance influences criminal behavior, but environmental factors also play a role.

Question 13

Evaluation

Problems with Adoption Studies

Answer 13

1.Many adoptees experience late adoption, spending significant time with biological parents.
2.Some maintain regular contact with biological parents, complicating the separation of genetic and environmental influences.
3.Mednick et al.’s study focused on petty crimes (e.g., burglary), limiting its application to more serious offenses.

Question 14

Evaluation

Biological Reductionism

Answer 14

1.Crime is complex; reducing it to genetic or neural explanations is overly simplistic.
2.Factors such as emotional instability, mental disorders, poverty, and social deprivation also contribute to criminal behavior.
3.Concordance rates for MZ twins are not 100%, suggesting other influences.

Question 15

Evaluation

Biological Determinism

Answer 15

1.The idea of a ‘criminal gene’ challenges the legal principle of personal responsibility.
2.Ethical concerns arise about how society might treat individuals suspected of having ‘criminal genes.’
3.Raises questions about sentencing and the potential for genetic profiling to influence justice systems.