🍒 Criminal Behaviour Biological Explanation- Inherited Criminality

Question 1

Lombroso’s Theory of the “Born Criminal”

Q: What did Cesare Lombroso propose about criminality?

Answer 1

• Criminals are biologically different from non-criminals.
• “Born criminals” can be identified by physical stigmata- abnormalities- (e.g., unusual head shape, facial asymmetry).
• Criminality is inherited, suggesting a genetic basis.

Question 2

Twin Studies & Heritability of Criminality

Q: How do twin studies support a genetic basis for criminal behaviour?

Answer 2

• Monozygotic (MZ) twins show higher concordance rates than dizygotic (DZ) twins.
• Christiansen (1977):
  35% concordance in MZ twins vs. 13% in DZ twins (Danish Twin Register, 3586 records).
• Suggests moderate genetic influence on criminality.

Question 3

The MAOA “Warrior Gene”

Q: How does the MAOA gene influence criminal behaviour?

Answer 3

• MAOA breaks down serotonin & dopamine.
• Low-activity variant → excess neurotransmitters → aggression & impulsivity.
• Brunner et al. (1993): Analysed Dutch family with violent males and histories of murder and rape had low MAOA activity.
• Tihonen et al. (2015): 5–10% of violent crime in - Finland linked to MAOA & CDH13.

Question 4

The CDH13 Gene & Criminality

Q: What role does CDH13 play in criminal behaviour?

Answer 4

• Regulates neural cell adhesion & connectivity.
• Linked to ADHD, impulsivity, and aggression.
• GWAS (2014): Associated with violent crime & homicide.

Question 5

Diathesis-Stress Model

Q: How does the diathesis-stress model explain criminality?

Answer 5

Genetic predisposition (diathesis) + Environmental stress → Criminal behaviour.

Caspi et al. (2002):
- Low MAOA + childhood maltreatment → Antisocial behaviour (Dunedin Study).
- Epigenetics: Environment can “switch genes on/off” (e.g., trauma affecting MAOA).

Question 6

Brain Differences in Criminals

Q: What brain differences are found in criminals?

Answer 6

• Reduced prefrontal cortex (PFC) activity (Raine, 2004):
  Impairs impulse control & emotional regulation.
• Neurotransmitter imbalances:
  Low serotonin → Impulsive aggression (Seo et al., 2008).
  Dopamine hyperactivity → Reward-seeking behaviour.
  Abnormal noradrenaline → Aggression (Wright et al., 2015).

Question 7

Gene-Environment Interaction (MAOA + Abuse)

Q: How does childhood maltreatment interact with MAOA?

Answer 7

• Low MAOA + Abuse → High antisocial behaviour risk.
• High MAOA + Abuse → Lower risk (protective effect).
  Shows genes alone don’t determine criminality; environment matters.

Question 8

Evaluation: Adoption Studies Support (Crowe, 1972)

Q: How do adoption studies support a genetic basis for criminal behaviour?

Answer 8

• Crowe (1972):
  Adopted children with criminal biological parents had a 38% risk of criminality vs. 6% for those without.
• Suggests genetics > upbringing in influencing criminality.
• Limitation: Doesn’t account for gene-environment interaction (not all with “criminal genes” offend).

Question 9

Evaluation: Explaining Non-Violent Crimes

Q: Why are biological explanations less useful for non-violent crimes?

Answer 9

• Blonigen et al. (2005): Genes link to psychopathy/violence, but fraud/drug crimes are more socially influenced.
• Crime is a social construct (laws change; e.g., cannabis legalisation).
• Counterpoint: Not all psychopaths are criminals → genes increase risk but don’t guarantee crime.

Question 10

Evaluation: Problems with Determinism

Q: Why is biological determinism flawed?

Answer 10

• Tiihonen et al. (2015): Low MAOA = 13x higher violent crime risk, but not all carriers offend.
• Supports soft determinism (genes + environment matter).
• Ethical issues: Genetic profiling could justify discrimination (e.g., “born criminal” stereotypes).

Question 11

Evaluation: Nature vs. Nurture Interaction

Q: How does gene-environment interaction explain criminality?

Answer 11

• Diathesis-stress model: Genes (e.g., MAOA) + trauma (e.g., abuse) → antisocial behaviour (Caspi et al., 2002).
• Epigenetics: Environment can activate/silence genes (e.g., stress altering MAOA expression).
• Shows both biology and upbringing are critical.

Question 12

Evaluation: Ethical Concerns

Q: What are the ethical issues with genetic explanations?

Answer 12

• Risk of eugenics: Could lead to stigmatisation of people with “criminal genes”.
• Self-fulfilling prophecy: Labeling someone genetically predisposed may increase criminal behaviour.
• Ignores rehabilitation (focuses on biology over change).

Question 13

Evaluation: Alternative Explanations

Q: What other factors explain crime besides genetics?

Answer 13

• Social learning theory (Bandura): Crime learned via observation/imitation.
• Poverty & inequality: Higher crime rates in deprived areas.
• Labelling theory (Becker): Being labelled a “criminal” leads to deviancy amplification.

Question 14

Holistic Approach Needed

Q: Why must criminal behaviour be studied holistically?

Answer 14

• Biological factors (genes, brain dysfunction) + psychological (impulsivity) + sociological (poverty).
• Example: Low serotonin + abusive upbringing + unemployment → higher crime risk.
• Reductionist theories (e.g., “MAOA causes crime”) oversimplify behaviour.

Question 15

Evaluation: Policy Implications

Q: How could genetic research impact crime prevention?

Answer 15

• Early intervention: Screen high-risk kids (e.g., low MAOA + abuse history) for targeted support.
• BUT: Risks privacy violations and genetic discrimination.
• Better to focus on social reforms (e.g., reducing poverty) than “fixing genes”.