Biological: Genetic and Neural Explanations Flashcards
What is the genetic explanation?
Suggests that criminals inherit a gene or a combination of genes that predispose them to commit crime
What was Lange’s twin study?
Investigated 13 MZ and 17 DZ twins, where at least one twin in each had served time in prison
He found - that 10 MZ and only 2 of the DZ twins had a co-twin who was also in prison suggesting that genetic factors do play a role
What was Christiansen’s twin study?
Studies 87 MZ and 147 DZ pairs and found concordance of 33% for MZ and 12% for DZ which supports the idea that offending may have a genetic component
What Tihonen’s research into candidate genes?
Analysed 900 offenders and revealed abnormalities on two genes that may be associated with violent crime - the MAOA gene (controls dopamine and serotonin in the brain and has been linked with aggressive behaviour) and CDH13 (been linked to substance abuse and ADD)
Individuals with this high risk combination were 13x more likely to have a history of violent behaviour - however this research is new and hasn’t been replicated
What is diathesis stress model?
Also applied to schizophrenia - a tendency towards criminal and behaviour may come about through a combination of genetic predisposition and biological and psychological triggers - being raised in a dysfunctional environment or having criminal role-models
What is the neural explanation?
APD is associated with reduced emotional response, a lack of empathy for the feelings of others and is a condition that characterises many criminals
What did Raine do/find?
Conducted many studies of APD brain reporting that there are several dozen brain imaging studies demonstrating that individuals with anti-social personalities have reduced activity in the prefrontal cortex (the part of the brain that regulated emotional responses)
Found an 11% reduction in the volume of grey matter in the prefrontal cortex of people with APD compared to controls
What is the role of mirror neurons?
Criminals with APD can experience empathy but do so less frequently than most
Keyers et al found that only when criminals were asked to empathise did their empathy reaction activate (controlled by mirror neurons)
This suggests that APD individuals are not totally without empathy but may have a neural switch that can be turned on and off unlike the normal brain where it is constantly switched on
What are the problems with twin studies?
Early studies had little control and zygosity was based on appearance rather than DNA testing - lacks validity Involve small samples and twins themselves are an unusual sample - not representative
Confounding variable - most twins are raised in the same environment so have a shared experience
What is the support for the diathesis stress model of crime?
Mendick - looked at 13,000 Danish adoptees and defined criminal as having at least one criminal conviction- that was checked against police records for each adoptee
When neither biological nor adoptee parents had a conviction the percentage of adoptees was 13%
When either biological or adoptive parents did = 20%
When both adoptive and biological parents did= 24.5%
Supports the model as we cant rule out the environment
What are the problems with adoption studies?
The presumed separation of environmental and genetic factors in adoption studies is complicated as many are adopted late which means that much of their childhood is spent with biological parents and many adoptees see their parents regularly so difficult to assess the environmental impact
Only those who committed minor crimes were included in Mendick’s study so any conclusions may not apply to violent crimes
What is biological reductionism?
Reducing offending behaviour to neural or genetic influences is too simplistic - crime does occur in families but so do mental health issues and poverty - makes it difficult to untangle the effects from the environment
Although concordance rates are different they are not 100%?
Ignores cognitive factors, freewill etc
What is biological determinism?
The ‘criminal gene’ creates a dilemma as the legal system is based on the premise that criminals have personal and moral responsibility for their actions only in case of mental illness can someone claim they are not acting under their own free will. This raises issues about the criminal gene and the implications it may have for sentencing
How is Mobley’s defence linked?
Robbed the store and shot a Dominos worker in the back of the head… his defence claimed he had a mutation in a gene linked with antisocial behaviour and he therefore wasn’t responsible - due to a lack of evidence he was sentenced anyway
