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bio explanation- genetics - Coggle Diagram
bio explanation- genetics
twin studies
lange
method
13 mz twin pairs
17 dz twin pairs
at least one had to be in prison
results
higher concordance rate for criminal behaviour in mz twins who had been imprisoned
10/13 mz twins showed concordance for criminality
2/17 dz twins showed concordance for criminality
adoption studies
crowe
investigated role of criminality in adoptees
method
biological mothers w/ criminal record vs those who didnt (control group)
results
higher risk adoptees w/ criminal bio mothers
50% did by 18 years old
5% of control group did
adoptive environment has little impact on biological predisposition
candidate genes
tiihonen et al
MAOA
control dopamine + serotonin in the brain
links to behavioural traits
aggression and impulsivity
'the warrior gene'
gives instructions on making an enzyme
monoamine oxidase A)
breaks down serotonin/ dopamine/noradrenaline
if these chemicals aren't broken down
higher baseline levels
different processing of baseline levels depending on brain regions
conducted genetic analysis
900 finnish offenders
had abnormalities on two candidate genes
13x more likely to have history of violent behaviour
CDH13
potential risk factor for neurodevelopmental/ psychatric conditions
e.g ADHD/ substance abuse
influences impulsivity
regulates connections between brain cells
diathesis stress model
pre-existing vulnerability and environmental stressors
e.g a faulty MAOA and CDH13 gene can be triggered by childhood trauma = criminality
EV
methodological flaws
shared environment applies more to mz twins
looking identical can influence treatment and therefore behaviour