My review on decision making and neuropsychiatry is here that I did over a decade ago. I think the last decade has taught me that we could do with learning a lot about how to measure abnormalities in decision-making in an objective way, and that there needs to be much greater convergence between neuroscience and the law. This review was published a long time ago in the world-leading journal Trends in Cognitive Sciences, and has, I feel, stood the test of time in the growing quantity and quality of research in this area.
For example, people can fly off the handle and kill their partner if provoked; this provocation defense in murder, bringing it down to manslaughter, is inadequately understood in terms of the neuroscientific mechanisms. Likewise, someone under law can lose it altogether at the drop of a hat, an ‘irresistible impulse‘, and bet billions on a horse winning the Grand National, and then refusing to pay because of a moment of madness (‘the insanity defense‘).
I feel, in my own area of dementia, quantifying risk-taking in behavioural variant frontotemporal dementia, will become important in the law. This is because currently the criminal courts have to rely on ‘expert evidence’, and it can be hard for a defense to argue for any organic basis for risky behaviour in the absence of any clear findings on a brain scan, for example. Especially when you consider that the standard of proof in the criminal courts is ‘beyond reasonable doubt’, this is of enormous significance. There may be a time when, if neuroscientific evidence can meet the Daubert standard, then they may be allowed in the defense of such a patient in the criminal courts. I have thought about this a lot, and have come to an important conclusion in parallel to this discussion; despite the rather disinhibited and risk-taking behaviour of some patients with behavioural variant frontotemporal dementia, it is rather rare for these behaviours to be criminal. I predict confidently, in the next decade, there will be a huge amount of work on the moral cognition of patients with behavioural variant frontotemporal dementia, especially in relation to that part of the brain I have written much about, the ventromedial prefrontal cortex.
Dr Shibley Rahman is an expert in behavioural variant frontotemporal dementia from Cambridge and London, and an active member of the World Neuroethics Society. In addition, he is a graduate of English law, and about to complete a Master of Law in London.
