Genetic + Neural explanations Flashcards
What do genetic explanations suggest about offenders?
Offenders inherit a gene or combination of genes that predispose them to commit crime.
Focuses on twin studies + adoption studies
What did Lange (1930) investigate?
Lange investigated identical (MZ) and non-identical (DZ) twins with one twin having served time in prison.
What were the findings of Lange’s study?
- 10 of the MZ twins had a co-twin in prison
- 2 of the DZ twins had a co-twin in prison
What did Christiansen (1977) study?
Christiansen studied 3500 pair of MZ + DZ twins to determine concordance rates for criminal behavior.
What were the concordance rates found by Christiansen?
- MZ twins: 33%
- DZ twins: 12%
Suggests behaviour + underlying predisposing traits = inherited
What did adoption studies by Crowe (1972) suggest?
Mother in prison = 50% risk of having criminal record by age of 18 vs 5% with bio mother not in jail.
What did Tiihonen et al (2014) find in their genetic analysis?
Genetic analysis of 800 Finnish offenders =
abnormalities on the MAOA and CDH13 genes are associated with violent crime.
What are the MAOA + CDH13 genes linked to?
MAOA = controls dopamine + serotonin in brain
CDH13 = substance abuse + ADHD
5-10% of violent crimes attributed to these genes.
How much more likely are individuals with abnormalities on both genes to have a history of violent behavior?
13 times more likely.
Why is it an issue for the study not to have been replicated?
Lack of replication raises questions about the reliability and generalizability of the findings.
What is the diathesis stress model?
It explains that genetic predispositions can be triggered by environmental stressors.
What is associated with anti-social personality disorder (APD)?
Reduced emotional responses + lack of empathy.
What brain area is linked to reduced activity in individuals with APD?
Prefrontal cortex.
(regulates emotional behaviour)
What did Raine (2000) find regarding the prefrontal cortex in individuals with APD?
An 11% reduction in grey matter.
What are mirror neurons?
Neurons that mirror the neural activity of another individual.
Allow us to experience empathy.
Switched on by default.
What did Keysers et al (2011) discover about criminals with APD?
Their empathy reaction can be activated when prompted.
Shows that people with ADP can experience empathy but by choice.
Fill in the blank: Individuals with APD have a neural switch to _______.
empathy.
Describe role of amygdala:
Raine et al (1997):
Studied murderers who were found not guilty by reason of insanity.
Compared with matched controls
Found abnormal symmtery in limbic system of murderers
Reduced activity in left amygdala.
What is the amygdala responsible for?
Controlling emotions + detecting threat.
