Biological Explanations Of Criminal Behaviour - Genetics Flashcards
What do genetic explanations for crime suggest?
That would-be offenders inherit a gene, or combination of genes, that predispose them to commit a crime.
Describe Christiansen’s (1977) twin study of offending behaviour and its results
Used a sample of 3,586 twin pairs - concordance rate of 35% for MZ twins and 13% for DZ twins (males).
21% MZ and 8% DZ (females).
Describe Raine’s (1993) twin study of offending behaviour and its results
Reviewed 13 twin studies - overall concordance rate of 52% for MZ twins and 21% for DZ twins
What are the 2 genes linked with violent crime?
MAOA - linked to aggressive behaviour
CDH13 - linked to substance misuse and ADD
Why does Brunner et al support the idea of candidate genes’ role in criminal behaviour?
Studied a family with history of aggressive and criminal behaviour - found that all male members had the MAOA gene
What do neural explanations of criminal behaviour suggest?
That there may be neural differences between brains of criminals and non-criminals. Much evidence in this area has investigated individuals with anti-social personality disorder - APD.
What is APD associated with?
Reduced emotional responses and a lack of empathy - characterises many convicted criminals.
What did Raine discovery about the Prefrontal Cortex?
Cited 71 brain imaging studies showing that murderers and psychopaths have reduced functioning in the prefrontal cortex. Lowered activity in this area is associated with impulsiveness and loss of control.
What did Raine discover about the Limbic System?
Used PET scanning techniques with 41 violent murderers vs. 41 non murderers - differences in brain activity in limbic system including the amygdala - these areas regulate emotions so can be linked to aggressive/violent behaviour
What is a limitation of the genetic & neural explanation of criminal behaviour? (Twin studies)
Could be argued that the difference in concordance rates are due to differences in environment and experiences of MZ & DZ twins - therefore not completely due to genes?
What is a strength of the genetic and neural explanations of criminal behaviour? (Diathesis-stress model)
Supports diathesis-stress model - Mednick et al - investigated 13,000 Danish adoptees. When bio & adoptive parents didn’t have convictions , % of adoptees that did = 13.5%. When both bio and adoptive parents did have convictions = 24.5% - suggests environmental influence cannot be disregarded
What is a limitation of the genetic and neural explanations of criminal behaviour? (Biological reductionism)
Criminality is complex - Katz et al found that crime does appear to run in families but so does emotional instability and mental illness - hard to differentiate a single cause - therefore may be overly simplistic and not appropriate explanations
