The ideas behind neurocriminology are not entirely new. Johann Lavater (1741-1801), a Swiss pastor, thought that you could tell criminality from a man’s face; Franz Joseph Gall (1758-1828), a German anatomist, from the bumps in his skull. Cesare Lombroso (1835-1909), an Italian doctor and criminologist, thought the same of a variety of physical stigmata; Karl Pearson (1857-1936), a British mathematician and militant socialist, thought that it was all in the genes, as did H. J. Eysenck (1916-1997), the British psychologist.

But let us leave aside the unlikelihood of neurocriminology shedding much light on why the rate of indictable crime in Britain rose nearly 4,000 per cent between 1900 and 1997, or why the homicidal attack rate should have increased by at least 1,000 per cent since 1960: what are the practical conclusions that are likely to be drawn from neurocriminology?

Some of them are very nasty indeed. They include sterilisation (once carried out by eugenicists); other surgical operations against people’s will; and an indefinite extension of state interference in people’s lives in the name of crime prevention.

Nor does neurocriminology, in logic, suggest merciful treatment of murderers who kill because of defective frontal lobes. Until such time as the defect can be repaired (which is likely to be never), it suggests extermination rather than mercy as the logical response.

The association between a condition of the brain and crime is never likely to be more than statistical at best. Indeed, a more definite relationship is virtually impossible. This means that there can be no one-to-one correspondence between the state of a person’s brain and his social or antisocial conduct. And this in turn means that there is a severe problem with false positives and false negatives.

Murder, even now, is a rare event, such that if a person with a certain kind of brain condition were a hundred times more likely than someone without it to commit a murder, he is still unlikely ever to kill. Thus, under neurocriminology’s direction, large numbers of people would be subjected to onerous and intrusive interventions without benefit to themselves or to society — only to the people administering the intervention. And, of course, many people who go on to commit murder would be missed by it in any case.

When one considers the difficulties in the comparatively straightforward task of screening for breast cancer, which has caused many women to undergo procedures that have done them no good, the scale of the problem for neurocriminology becomes obvious.

Of course, this would not deter incipient totalitarians, such as our politicians. Indeed, neurocriminology will be music to their ears.

It will also be music to the ears of criminals, actual and potential, whose sense of personal responsibility it will further erode. “It wasn’t me,” will be the cry, “it was my brain.” Such understanding will not be extended to the police, the jury or the sentencing judge.

Paradoxically, then, neurocriminology will serve to increase the very criminal mindset that it aims and claims to detect and prevent.

First published in The Times.