bio explanation 2 : genetics - for offending

Lange - twin study 1930

• Method: studied 13 pairs of MZ twins and 17 pairs of DZ twins where one twin in each pair had been imprisoned - Lange found higher concordance rate for criminal behaviour in MZ twins (where both twins been imprisoned) compared to DZ twins

• Results: reported 10/13 MZ twin pairs showed concordance rates for criminality, whereas only 2 out of 17 DZ twin pairs did.

• Concl: Lange concl genetic factors played a predominant role in criminal behaviour, suggesting a strong inherited predisposition to crime

Crowe 1972 - adoption study

• method: investigated role of genetics in criminality by comparing adopted children whose bio mothers had a criminal record with a control group (adopted kids) whose mothers didnt

• Results: key finding was adopted children w a criminal bio mothers had a significantly higher risk (around 50%) of having a criminal record by the age of 18 compared to control group (5%)

• Concl: suggested genetic factors transmitted from bio mothers played significant role in predisposing individuals to criminal behaviour even when raised in different environments

Tihonen et al - candidate genes 2014 AND MAOA gene and CDH13 gene

• conducted genetic analysis of 900 Finnish offenders to reveal abnormalities on 2 candidate genes that may be associated with violent crime. Within sample, individuals with this high risk combo were 13x more likely to have history of vio behaviour

• MAOA gene: Controls dopamine and seratonin in brain - variations linked to aggression = nicknamed ‘warrior gene’ : breaks down seratonin, dopamine, etc , lower amounts of enzymes being produced, chemicals aren’t broken down

• CDH13 gene: identified as potential risk factor for various conditions like ADHD and substance abuse : this gene helps regulate connections between brain cells, may influence impulsivity

Diathesis stress model with evaluation

• explains offending behaviour as a combination of pre existing vulnerability = (e.g diathesis being genetics) and environmental stressors

• Diathesis makes someone more susceptible to crime, but stress triggers this predisposition - stronger diathesis = less stress is needed

• AO3: genetic explanation supports diathesis stress model

• Study of 13,000 danish adoptees by Mednick et al found when neither bio or adoptive parents had convictions, 13.5% of the adoptees did, figure rose to 20% when either bio parent had convictions and 24.5% when both adoptive and bio parents had convictions

• Demonstrates genetic inheritance plays role but environmental influence also is important

• Whilst diathesis stress model reduces genetics down to partial role = still a crucial component of why people offend

Ao3 - theoretical flaw = biologically reductionist - low level of expl

• theory suggests if an individual possesses certain candidate genes like the warrior gene, they are predisposed to criminal behaviour

• Oversimplifies intricate web of factors that contribute to offending and reduces complex behavioural patterns to single, bio cause, ignores other crucial influences like socioeconomic status (education) or deviant role models

• Genetic explanation = more useful when used within diathesis stress model

Ao3 - issue = biologically deterministic

• e.g genetic expl suggests that offending behaviour is determined by inherited faulty genes which cannot be controlled by the person, suggests a person shouldn’t be held responsible for any crimes they commit as they have no free will. However our justice system is based on notion we all have responsibility for our actions

• Identification of possible bio precursors to crime complicates this principle and raises social sensitivity issues

• Taking free will out of equation of why people offend is a controversial idea