Twin studies (AO1)

• Monozygotic twins share 100% of their genetic material and are more likely to have similar criminal behavior compared to dizygotic twins.
• Twin studies can provide evidence for the heritability of criminal behavior by comparing the criminality rates of monozygotic and dizygotic twins.
• If The concordance rate for criminal behavior is higher in monozygotic twins compared to dizygotic twins, suggesting a genetic influence on criminality.
• The shared environment between twins, such as upbringing and family dynamics, can contribute to criminal behavior.
• Key study : Christiansen (1977)

  Investigated the concordance rate between 3,500 twin pairs in Denmark
• key study findings : Christiansen


  male MZ twins 35% concordance rate

  male DZ twins 13% concordance rate

  female MZ twins 21% concordance rate

  female DZ twins 8% concordance rate