Genetic Explanations AO3

• how is Christiansen's study a strength of the genetic explanation for offending behaviour?

  • studied over 3500 twin pairs in Denmark and found a concordance rate for offending behaviour of 35% in MZ male twins and 13% in DZ male twins, indicating a genetic component is involved
  • however, small percentage even in genetically identical twins, so when generalised to real world where everyone is genetically different, percentage will be even smaller
• how is Crowe's study a strength of the genetic explanation for offending behaviour?

  • found that if a biological mother had a criminal record, 50% of the adopted children also had one by the time they were 18 compared to a control group of only 5% with a criminal record, suggesting a genetic predisposition to criminality
  • affect still seen even with strong external environmental changes through their life
• how is Brunner's study a strength of genetic explanation for offending behaviour?

  • conducted an analysis of a large family in the Netherlands, a number of whom had been responsible for various counts of anti-social behaviour and criminal behaviour, they found a deficiency/variant of MAOA gene which regulates serotonin and is linked to aggression
  • found that deficiency needs to be combined with psychological trigger like maltreatment to have an impact - Diathesis-Stress model
• what does the Diathesis Stress Model indicate?

  • tendency towards offending behaviour may be a result of a genetic predisposition and a psychological trigger, suggesting that genetics alone can't explain criminal behaviour
  • more interactionist approach may need to be taken which is less socially sensitive
• what are scientific issues with twin studies?

  • twins are unique and may have a different experience to the general population who are not twins, thus it may not always be appropriate to generalise from twins to all non-twins
  • twin studies assume MZ and DZ share similar environments, however this isn't the case, however an issue is that MZ are often treated more similarly than DZ, thus making an explanation for higher concordance rates
• what is a scientific issue with adoption studies?

  • assume that nature and nurture can be distinguished, however many adoptions take place when children are older and so spend several years with their biological parents, thus an environmental influence may still be present
• what does biological determinism suggest concerning genetic explanations for offending behaviour?

  • suggests offending behaviour is determined by genetic factors which cannot be controlled by the person, thus they should not be blamed or be responsible for their crimes
  • doesn't necessarily work in our criminal justice system and wider society, where we are responsible for our actions, as some people would argue that genetic factors could be an excuse to justify criminal actions
• how is the Stephen Mobley case relevant?

  A convicted murderer executed by the state of Georgia for the 1991 killing of John C. Collins, on appeal Mobleys attorneys advanced a novel argument that Mobley was genetically predisposed to seeking violent solutions to conflict, described as the most widely cited case where genetic factors were used in defence