THE irony would be delicious-if it wasn鈥檛 so serious. For years, all good liberals have been waging war against research into the biological basis of criminality, believing it to be a step towards Nazi-style extermination of undesirables. Then along come criminals and their lawyers embracing the science with open arms.
First to catch their eye a few years ago was the idea of 鈥渃riminal鈥� genes . 鈥淒on鈥檛 blame me, my DNA made me do it鈥� became the fashionable plea. Now brain scans are all the rage in court (see p 16) and the new plea is: 鈥淒on鈥檛 blame me, my frontal lobes weren鈥檛 working properly鈥�.
Brain researchers are right to be alarmed about this abuse of their science. And yet the lawyers are only doing what clever lawyers are paid to do. What really irks is the number of brain-imaging experts who are apparently willing to give the lawyers what they want-a simplistic view of what the technique can reveal about the reasons people commit crimes.
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In fact, the brain scans in question only reveal what is blindingly obvious. If a man shoots and kills a policeman at close range without a motive, you don鈥檛 need a PhD in neurology to work out that his judgment was probably impaired. Impaired judgment goes hand in hand with most violent crime. We know that because in most countries alcohol is involved in more than 90 per cent of murders.
What really matters in assessing that defendant鈥檚 guilt and the appropriate punishment, is whether he was oblivious to the difference between right and wrong.
And unfortunately or fortunately, depending on your point of view, there isn鈥檛 a brain-imaging technique in the world that can establish that. Neuroscientists have a hard enough time working out how the brain creates the mental illusion of visual perception, let alone the illusion of moral judgment and free will.
But let鈥檚 be clear about this. Violent crime does have some connection with involuntary, disturbed patterns of brain activity in the frontal lobes: in some criminals, it probably has a lot to do with it. The problem is that we could never know what (if any) part such individual 鈥渘eural signatures鈥� might have had in shaping or triggering any particular bit of impulsive or criminal behaviour. The science isn鈥檛 even precise enough to say whether this or that patch of unusually low brain activity in a scan was caused by drug abuse, a difficult birth, genes-or watching too much TV.
Brain scans can make a valuable contribution to the business of crime and punishment. Outside the courtroom, psychiatrists could use them more often to decide which violent criminals could benefit most from medication or from being housed in specialist hospitals. In other words, brain imaging should be used for what it was designed for-diagnosing medical conditions, not moral ones.
