By Professor Steven Rose
Professor of Biology, Open University
Connections between crime and biological make-up are increasingly becoming a hot topic for discussion. Two personal and opposing accounts argue the case for and against.
Professor Steven Rose sets out his views below.
There is a revealing moment in the IF drama in which the "lecturer" addressing his class of bored students shows a picture of the Jarrow hunger march in the 1930s.
Professor Rose: "People are violent for many different reasons"
If poverty is the cause of violence, he asks, why was there relatively little of it then, but so much more today?
He concludes the cause must be located in the brain and in the genes.
It is true that there has been an increase in violent crime since the 1960s, and an even greater increase, fostered by the tabloid press and the government, in the fear of crime.
However, what any alert student would quickly have pointed out to the lecturer is as there cannot have been time since the 1930s for genetic change to occur, as it requires hundreds of generations.
Since our brains remain the same now as they were then, the genetic argument cannot be right either.
IF... WE COULD STOP THE VIOLENCE
Wednesday, 22 December, 2004
And of course as a child gets half its genes from its father and half from its mother, the refrain in the programme of "like father like son" is a crass genetic error.
If Liam has ADHD (if that were a sensible diagnosis, which many child psychologists would doubt), and if ADHD were a genetic condition (for which there is no strong evidence), then it would be as likely to be inherited from his mother as his father.
If there is more violent crime today we have to look for other reasons than inside peoples' brains.
Guns and drugs other than alcohol and nicotine are more available, there is a growing gap between rich and poor, and life in sink estates, perhaps especially for young men, offers little hope.
But despite all this, one might argue that maybe there is something different about the brains or the genes of someone prepared to be violent, and that a genetic test or a brain imaging, as in the programme, might reveal it.
This is only true up to a point.
There is some evidence that children with a particular genetic mutation, if brought up in an abusive environment, are more likely to be violent or abusive in turn when they become adult.
But the crucial factor is the interaction between gene (which is rare) and environment (which is common), so if we want to do something about it we should try to prevent any child, with or without any particular gene, from being abused.
There is also some evidence that some people diagnosed as psychopathic may show particular brain abnormalities.
But many people so diagnosed do not show such abnormalities, and many people who are behaviourally not violent do show them.
So the predictive power of such a brain scan is pretty much zero.
Furthermore of course, people are violent for many different reasons, almost none of which are detectable by brain imaging.
I doubt if you would be able to explain the reasons why they have been responsible for some 100,000 deaths in Iraq by doing brain scans on Tony Blair or George W Bush, to take an extreme example.
Nor would the violence of someone addicted to crack cocaine and desperate for a fix be attributable to some genetic or neural predisposition.
The truth is that neuroscience and genetics can say little about the causes or the treatment of violence in our society and cannot offer cheap fixes.
Beware forensic psychologists who say anything different, however glib they may sound.
They are selling snake oil.
Professor Steven Rose was a contributor to BBC Two's If... We Could Stop The Violence, broadcast on Wednesday, 22 December 2004, at 2100 GMT.