NPR News broadcast three in-depth installments narrated by Barbara Bradley Hagerty in the past three days about the latest findings on the genetic and neural underpinnings of criminal behavior and how these insights may influence sentencing in court.
The product of the gene MAOA discussed in the first installment entitled "A Neuroscientist Uncovers A Dark Secret" is the enzyme monoamine oxidase A. This enzyme breaks down the neurotransmitters dopamine, noradrenaline and serotonin. Modifications of this gene have been associated with an elevated risk for criminality (Guo and others, 2008). Persistently increased levels of dopamine may result in volatile, aggressive behavior. The research discussed in the NPR broadcast was conducted with the principal investigator's own family members and awaits publication in a peer-reviewed scientific journal. The identification of a large number of genes associated with mental disorders like autism may serve as a reminder that it is unlikely that the defect of only one gene may cause a behavior that is the result of multiple complex nerve cell interactions in the brain.
The second installment entitled "Inside A Psychopath's Brain: The Sentencing Debate" reports on evidence obtained with functional magnetic resonance imaging (fMRI) that convicted psychopaths viewing scenes with content needing moral judgment show abnormal activation of cerebral cortex. The principal investigator recently co-authored a study of similar design in which read statements were used instead of visual scenes (Harenski and others, 2010).
The identification of genes with gene chip analysis as well as the identification of activated brain regions with fMRI that may play a role in criminality are probabilistic with attached uncertainties. The third NPR News installment entitled "Can Your Genes Make You Murder?" informs us about the impact of the science discussed in the prior installments on a recent court decision in the state of Tennessee as an example of the advent of neurolaw, that is the inclusion of neuroscience in criminal law.
As intriguing as the scientific observations on the workings of the criminal brain may be, the science remains in its infancy. Examining the brains of convicted felons does not permit us to determine whether the detected changes are the result or the cause of the criminal behavior. A genetic modification statistically associated with criminal behavior may point to a potential hazard. Yet, only the committed crime provides the necessary affirmation.
Therefore, judgment in court will remain based on the offenders' decisions and actions. The difficulty of our judgment is brought into focus, however, when we are confronted with people who are perfectly able to make informed decisions and know right from wrong in every-day life, but who commit the most horrible crimes when the conditions are right with a good chance of repeating such crimes in a similar situation.
Are psychopathic offenders capable of repentance? Will incarceration improve them? Is it possible to 'cure' their affliction or will they forever remain too dangerous to be allowed to live among us unsupervised again?
These questions are as old as mankind. Whether neuroscience will help us find better answers remains to be seen.
I expressed my ambivalent feeling towards neurolaw in a poem when the term evolved into a buzz word. The poem is written in magic ink. The writing takes some time to unfold:
- Guo G, Ou XM, Roettger M, Shih JC (2008) The VNTR 2 repeat in MAOA and delinquent behavior in adolescence and young adulthood: associations and MAOA promoter activity. Eur J Hum Genet 16: 626-634.
- Harenski CL, Antonenko O, Shane MS, Kiehl KA (2010) A functional imaging investigation of moral deliberation and moral intuition. Neuroimage 49: 2707-2716.