genes - evaluation

• RESEARCH EVIDENCE - supports ROG in CB

  Raine (93) - reviewed research on delinquent B of Mz and Dz twins

  52% concordance rate in Mz compared to 21% in Dz

  suggests - genetically identical people are more likely to share delinquent behaviour

  EXT - expect higher concordance rate for MZ twins if there was a gene that causes delinquent behaviour

  - therefore while twin studies support ROG in CB > doesn't prove that genes are 100% responsible for CB
• RESEARCH EVIDENCE - supports RO defective variant of MAOA gene in CB

  Hans Brunner et al (93) - analysed DNA of 28 male members of Dutch family

  history of impulsive and violent crimes (rape and murder)

  shared particular variant of MAOA > abnormally low levels of MAOA enzyme

  supports - genes play central but indirect role in regulation of our moods and ability to control out B

  EXT - displayed low IQ, introverted, little social inclusions and social activities

  history of frequent violent outbursts with little justification, occur during periods of little sleep and night terrors
• ADOPTION STUDIES

  twin studies fail - separate RO bio and environment in development of CB > adoption studies may be a more valid source of info

  many TS - suggest MZ = higher concordance rate for CB than DZ - could due to shared genes / raised in identical manner > therefore - not certain that TS support ROG in CB as it could be supporting the role of environmental influences
• ADOPTION STUDIES - 2

  however - some psychologists investigates CB rates among people who were bio related but didn't share the same environment (bio parents = criminal but raise in non-c adoptive family)

  many of these show - when reach adulthood > kids of C bio parents - more likely to become criminal - compared - people not from C bio parents but adoptive families were C

  suggests - inherited genes = stronger influence on future CB than environment
• ADOPTION STUDIES - Evidence

  Mednick et al (87)

  investigated bio and adoptive backgrounds of 14,000 adoptees

  15% of sons adopted to C family went on to become criminals - compared - 20% whose bio parents were criminal
• DETERMINISM

  G exp - genes person is born with determines their later behaviour > not supported in society

  evidence doesn't support this

  Tiihonen et al (15) - those with defective gene = 13 times more likely to have a history of repeated violent crime > means not everyone with this genetic variation became criminal
• DETERMINISM - 2

  Case studies of real life trials show that courts aren't willing to accept genetic backgrounds as justifiable explanations for CB

  > Stephen Mobley - generations of family who committed violent crimes, he was tested for variant of MAOA genes > judge - RE not strong enough to show causal link between genes and CB

  our judicial system reflects society's views that crimes are committed under criminal's free will and they should be held morally responsible for actions as they had a choice to do them

  therefore - may widespread reluctance to accept a genetic explanation of CB
• APPLICATIONS - MODIFYING CB

  can apply exp that CB - inherited through genes by using Genetic Engineering to decrease amount of criminals in society

  • extreme = end reproductive capabilities of people carrying defective variant of MAOA/CDH13 > similar to highly unethical practice of eugenics
  • moderate = remove defective criminal genes after fertilisation and replace with non-defective gene

  could eliminate criminality from gene pool and should reduce the amount of criminals in society

  clear ethical and economic benefits
• GENES AND ENVIRONMENT

  Capsi

  children with trauma and MAOA > higher levels of antisocial behaviour and criminality

  higher than those without gene