Forensics: genetic and neural explanations

Question 1

summarise the neural explanation of offending

Answer 1

• dysfunctions of the brain and nervous system.
• includes the activity of brain structures such as the hypothalamus and neurotransmitters such as serotonin and dopamine.
• Evidence suggests there may be neural differences in the brains of criminals and non-criminals.

Question 2

summarise the genetic explanation of offending

Answer 2

• Offenders inherit a gene, or combinations of genes, that predispose them to commit crime.
  E.g.
• Twin studies
• Adoption studies
• Candidate gene
• Diathesis-stress model

Question 3

Explain how adoption studies are evidence of genetic explanation of offending (Crowe)

Answer 3

• Crowe, compared group of adopted children whose biological mother had a criminal record to control group whose mothers did not have a criminal record.
• those with criminal mother, 50% of adopted children also had a criminal record by 18 years old.
• control group: only 5% of adopted children had criminal record by the time they were 18.
• suggests regardless of environment, children seem biologically predisposed to criminality.

Question 4

Explain a family study that is evidence for the genetic explanation of offending (Brunner, Netherlands)

Answer 4

• Brunner studied large family in the Netherlands.
• found anti-social and criminal behaviour: rape and arson.
• diagnosed with Brunner Syndrome.
• found lower iq avg of 85.

Question 5

Explain how candidate genes support the biological explanation (Tiihonen) (Finnish offenders) (MAOA) (CDH13)

Answer 5

• Tiihonen conducted genetic analysis of 900 Finnish offenders.
• MAOA -> controls dopamine and serotonin, links with aggression.
• CDH13 (protein coding) -> Linked to substance abuse and attention deficit disorder.
• Conclusion: Individuals with abnormalities on both genes were 13 times more likely to have a history of violent behaviour.

Question 6

Explain how an extra Y chromosome is evidence for the biological explanation (Jacobs)

Answer 6

• Jacobs e al. (1965) found a higher percentage of people from a prison population had the atypical sex chromosome pattern XYY.
• Led to increased testosterone and increased violence.
  -> people with this chromosomal abnormality are more likely to be hyperactive, impulsive and have a lower IQ which may explain their criminality.

Question 7

Explain how reduced activity in the prefrontal cortex (PFC) is evidence for the neural explanation (Raine)

Answer 7

• Raine (2000) found an 11% reduction in the volume of grey matter in the PFC of people with APD (antisocial personality disorder) compared to control groups.
• prefrontal deficits can lead to someone being more impulsive and emotional.
  -> Amygdala: controls urges and desires.

Question 8

Explain how mirror neurons are evidence for the neural explanation (Keysers)

Answer 8

• only when criminals were asked to empathise with others (person being depicted on film experiencing pain), their empathy reactions were activated.
• This is controlled by mirror neurons.
  -> suggests APD individuals do experience empathy, although it is not an automatic response.
  -> These neurons fire in response to the actions of others.

Question 9

List the evaluations for the neural and genetic explanation of offending

Answer 9

Positive:
- evidence for the candidate gene (Tiihonen)
- support for diathesis-stress model

Negative:
- biological reductionism
- biological determinism

Question 10

(+) explain evidence supporting the role of the candidate gene for the genetic explanation (Tiihonen)

Answer 10

• Tiihonen investigated violent and non violent criminals.
  -> 78 were rated as extremely violent.
• ‘warrior gene’ -> non-violent criminals did not have this.
• alcohol and drug abuse is shown to cause hyperactivity in dopamine levels.
• all extremely violent criminals had consumed drugs or alcohol before committing their crimes.

Question 11

(+) explain evidence supporting the diathesis-stress model of crime (Mednick)

Answer 11

• Mednick did a Danish adoptees study.
  -> found genetic inheritance plays a role as do environmental influences

Question 12

(-) explain how the biological and neural explanation is reductionist (Katz)

Answer 12

• criminality is complex -> these explanations can be simplistic and inappropriate.
• Katz -> crime can run in families but so does emotional instability, social deprivation and poverty -> therefore other factors must be in play.
• no study has found 100% concordance rate between identical MZ twins for criminality and often these rates have been low.

Question 13

(-) explain how the biological explanation is deterministic

Answer 13

• the concept of a ‘criminal gene’ presents ethical problems for our legal system since it negates free will.
• ethical question on how society treats people who carry ‘criminal genes’
  -> problems for society -> implications for sentencing.

Question 14

Explain the diathesis-stress model (genetic and neural explanation) (Ripke)

Answer 14

• Link between genetic predisposition and psychological trigger.
• E.g. being raised in dysfunctional environment or having criminal role models.
• Ripke: trauma such as child abuse can affect hypothalamic pituitary adrenal system.