L4 - Genetic and neural explanations Flashcards
what are genetic explanations for crime?
offenders possess a certain gene within their DNA that causes them to become criminals, or combination of genes for arguments sake
What did LANGE investigate?
Investigated 14 monozygotic (identical) twins and 17 dizygotic (non identical) twins.
LANGE’s RESULTS
at least one of the twins in each pair had served time in prison. 10 of the 13 pairs of MZ twins had both spent time in prison whereas only 2 of the 17 pairs of DZ twins had both spent time in prison
criminal behaviour could be polygenic
this means that no one single gene is responsible for offending; instead many genes might be responsible for causing criminal behaviour and they are known as CANDIDATE genes
what did TILHONEN ET AL do?
conducted a genetic analysis of over 900 Finnish offenders which revealed abnormalities on two genes that may be associated with violent crime
what were the two genes associated with violent crime?
1) MAOA gene - controls dopamine ad serotonin in the brain and has been linked to aggressive behaviour
2) CDH13 - has been linked to substance abuse and attention deficit disorder.
Within the Finnish sample individuals with this high risk combination of genes were 13x more likely to have a history of violent behaviour compared to a control group
diathesis stress model
states that genetics influence criminal behaviour but this is moderated by the effects of the environment. A tendency towards criminal behaviour comes from a combination of genetics and biological or psychological triggers, such as being raised in a dysfunctional environment.
what are neural explanations for crime?
there may be neural differences between the brains of criminals and non criminals. Many criminals have a condition called anti social personality disorder (APD) - which is associated with reduced emotional responses and a lack of empathy.
what neural differences can be seen amongst individuals with APD?
reduced activity in the pre frontal cortex of the brain - this is the area that regulates emotional behaviour.
RAINE ET AL STUDY INTO NEURAL DIFFERENCES
RAINE ET AL found an 11% reduction in the volume of grey matter in the prefrontal cortex of people with APD compared to a control group.
what does research show about criminals with APD?
criminals with APD can experience empathy but they do so more sporadically than the rest of us. KEYSERS ET AL found that only when criminals are asked to empathise did their empathy reaction (controlled by mirror neurons) activate.
what does the empathy reaction in KEYSERS ET AL study show about APD individuals?
APD individuals are not totally without empathy but may have a neural switch that needs to be turned on in order to experience it. In a normal brain this isn’t the case and its much easier for us to feel empathy.
EV: (-) CONCORDANCE RATES
concordance rates in MZ twins are not high and leave a lot of room for environmental factors, concordance rates may be due to shared learning experiences rather than genetics
EV: (-) BRAIN SCANNING STUDIES
brain scanning studies such as RAINE ET AL show differences but cannot conclude the causes of these difference, it could be signs of early abuse instead.
EV: (-) wording is too vague
the term offending behaviour is too vague, some specific forms of crime may be more biological than others such as crimes involving aggression whereas something like fraud is taught through environmental means.
