Genetic And Neural Explanations

• Diathesis-stress model (genetics)

  •Offending behaviour is argued to be the result of both an underlying (genetic) predisposition (diathesis) and an environmental trigger (stress – e.g. being raised in a dysfunctional environment or having criminal role models). Both are necessary for offending behaviour to occur.
• Eval Twin Studies

  •Early twin studies such as Lange’s research were poorly controlled and judgements related whether the twins were MZ or DZ) were based on appearance rather than DNA testing.•Furthermore, MZ twins often share a more similar environment than DZ twins as they are typically treated more similarly by adults and peers. This acts as a confounding variable.••Therefore, from the research, it is not possible to separate the effects of genes and the environment and so the research cannot strongly support the genetic explanation of offending behaviour.
• Eval-Is Criminality Too Complex

  •Criminality is complex, and explanations that reduce offending behaviour to a genetic or neural level may be inappropriate and overly simplistic.•Whilst crime does appear to run in families, so do emotional instability, mental illness, social deprivation and poverty. This makes it difficult to disentangle the effects of genes and neural influences from other possible factors.•Additionally, whilst there is often a difference in concordance rates between MZ and DZ twins, MZ twins do not show 100% concordance.
• The notion of a criminal gene

  Presents an ethical dilemma
• Taking the stance that the offender has no responsibility for their actions


  Could cause significant psychological harm to their victims and have implications for treating offender behaviour
• Our legal system is based on the premise that criminals have personal and moral responsibility for their crimes
• Only in extreme cases, such as a diagnosis of mental illness, can someone claim they were not acting of their own free will
• The Mobley case raised questions as to whether the individual's genetic make-up could be used as a defence in criminal cases
• Eval-Cause And Effect

  •One issue with neural explanations is whether abnormalities in regions of the brain or levels of neurotransmitters are the cause of offending behaviour or the result of it.•Research only highlights a correlation between activity of the prefrontal cortex and criminality. Therefore, offending behaviour may reduce the activity of the prefrontal cortex.•Therefore, the research cannot provide strong support for the internal validity of the neural explanations as cause and effect cannot be determined.
• Eval- Application

  •Neural explanations could lead to potential methods of treatment. For example, if low serotonin caused increased aggressiveness in criminals, people in prison could be given diets than enhance serotonin levels and hopefully decrease their aggression.••This supports the external validity of the neural explanations as they have the potentially for utility in reducing offending behaviour.
• Eval-Can It Explain All Crime

  •Most of the genetic and neural research relates to the association between these factors and violent or aggressive crimes. However, offending behaviour also includes theft, fraud, drug use and bigamy – all non-violent crimes.••Biological explanations may just account for certain types of crimes such as those involving violence and psychopathy and so not be entirely externally valid.