Forensics: genetic and neural explanations Flashcards
summarise the neural explanation of offending
- 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.
summarise the genetic explanation of offending
- 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
Explain how adoption studies are evidence of genetic explanation of offending (Crowe)
- 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.
Explain a family study that is evidence for the genetic explanation of offending (Brunner, Netherlands)
- 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.
Explain how candidate genes support the biological explanation (Tiihonen) (Finnish offenders) (MAOA) (CDH13)
- 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.
Explain how an extra Y chromosome is evidence for the biological explanation (Jacobs)
- 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.
Explain how reduced activity in the prefrontal cortex (PFC) is evidence for the neural explanation (Raine)
- 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.
Explain how mirror neurons are evidence for the neural explanation (Keysers)
- 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.
List the evaluations for the neural and genetic explanation of offending
Positive:
- evidence for the candidate gene (Tiihonen)
- support for diathesis-stress model
Negative:
- biological reductionism
- biological determinism
(+) explain evidence supporting the role of the candidate gene for the genetic explanation (Tiihonen)
- 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.
(+) explain evidence supporting the diathesis-stress model of crime (Mednick)
- Mednick did a Danish adoptees study.
-> found genetic inheritance plays a role as do environmental influences
(-) explain how the biological and neural explanation is reductionist (Katz)
- 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.
(-) explain how the biological explanation is deterministic
- 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.
Explain the diathesis-stress model (genetic and neural explanation) (Ripke)
- 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.
