A01

• What do genetic explanations for crime suggest about offenders?

  They inherit genes that predispose them to crime
• What do twin studies illustrate about the importance of genes in criminal behavior?

  • Higher concordance rates in identical twins (35%)
  • Lower concordance rates in non-identical twins (13%)
  • Suggests genetic influence on offender behavior
• Who studied over 3500 twin pairs in Denmark?

  Karl Christiansen
• What were the concordance rates for identical and non-identical twin males found by Christiansen?

  35% for identical, 13% for non-identical
• What years were the twins studied by Christiansen born?

  Between 1880 and 1910
• How was offender behavior checked in Christiansen's study?

  Against Danish police records
• What did Christiansen's data indicate about inherited behavior?

  It includes underlying predisposing traits
• What did Raymond Crowe find about adopted children with criminal biological mothers?

  50% risk of a criminal record by age 18
• What was the risk of a criminal record for adopted children without a criminal biological mother?

  5% risk by age 18
• What did Jari Tihonen's genetic analysis of Finnish offenders suggest?

  • Two genes linked to violent crime: MAOA and CDH13
  • MAOA regulates serotonin and is linked to aggression
  • CDH13 linked to substance abuse and ADHD
  • 5-10% of severe violent crime in Finland is attributable to these genes
• What does the MAOA gene regulate?

  Serotonin in the brain
• What is the link between the CDH13 gene and behavior?

  Linked to substance abuse and ADHD
• How does the diathesis-stress model relate to offending behavior?

  • Combines genetic predisposition with environmental triggers
  • Examples: dysfunctional upbringing or criminal role models
  • Suggests that genetics alone do not determine behavior
• What might moderate the influence of genetics on offending behavior?

  The effects of the environment
• In which other condition has the diathesis-stress model been applied?

  Schizophrenia
• What can trigger a tendency towards offending behavior according to the diathesis-stress model?

  Biological or psychological triggers
• How do genetic predispositions and environmental factors interact in the context of crime?

  They combine to influence offending behavior