By Professor Adrian Raine
Professor of Psychology, University of Southern California
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 Adrian Raine sets out his views below.
Until recently it was thought that the causes of crime lay just in social factors like poverty and unemployment.
Professor Raine: "The evidence is too strong to ignore"
Yet repeat offending criminal behaviour is a clinical disorder, with brain impairments playing a key role.
New research is now showing that genetic and biological factors play an equal, if not greater, role than social factors in crime causation.
Within this new field of biocriminology, brain imaging findings are revealing dramatic new insights into the criminal mind.
There are now 71 brain imaging studies showing that murderers, psychopaths, and individuals with aggressive, antisocial personalities have poorer functioning in the prefrontal cortex - that part of the brain involved in regulating and controlling emotion and behaviour.
IF... WE COULD STOP THE VIOLENCE
Wednesday, 22 December, 2004
More dramatically, we now know that the brains of criminals are physically different from non-criminals, showing an 11% reduction in the volume of grey matter (neurons) in the prefrontal cortex.
Violent offenders just do not have the emergency brakes to stop their runaway aggressive behaviour.
Literally speaking, bad brains lead to bad behaviour.
Dramatic advances are also being made in the areas of molecular and behaviour genetics.
Over 100 twin and adoption studies have convincingly shown that genetic processes account for 50% of antisocial and criminal behaviour.
Of the remaining half that is environmental, biology accounts for part of this. For example, physical child abuse can cause brain damage that in turn results in antisocial, aggressive behaviour.
Genetic processes are also at play in shaping aggressive behaviour in children.
There is exciting new evidence that an abnormality in one specific gene (monoamine oxidase A), when combined with child abuse, predisposes to violent offending in adulthood.
In a similar fashion, birth complications, when combined with maternal rejection in the first year of life, results in higher violence at age 34.
The biological and genetic findings are now incontrovertible; the evidence is too strong to ignore.
These new breakthroughs have important implications for crime prevention.
One of the reasons why we have repeatedly failed to stop crime is because we have systematically ignored the biological and genetic contributions to crime causation.
We instead need to focus efforts on new interventions that will improve brain structure and function.
New research has just shown that childhood malnutrition is linked to poor brain functioning (low IQ) and conduct disorder in early adulthood.
Giving three-year-olds better nutrition (and more physical exercise) for just two years results in better brain functioning (EEG) at age 11, and a 35% reduction in crime 20 years later at age 23.
Prisoners given fish oil (rich in omega-3, a long-chain fatty acid that is critical for brain structure and function) show reduced aggressive and antisocial behaviour.
Low physiological arousal (e.g. low sweat and heart rates) is a well-replicated risk factor for crime and violence, but stimulants (drugs which increase arousal) are effective in reducing aggressive and antisocial behaviour in children.
Where will this new biological approach take us?
If we really want to stop crime, the best investment society can make is to intervene very early on.
Better prenatal and perinatal health care, better nutrition early in life, and medication for severely aggressive children can be implemented right now.
The next decade will reveal new discoveries regarding specific genes that cause violent behaviour, and these findings could result in new drugs to correct the neurotransmitter brain abnormalities that cause violence.
In 50 years time, will we be conducting reparative brain surgery on prisoners to correct the faulty neural circuits that give rise to violence?
Rocket science perhaps - but there is an uncanny habit for today's science fiction to become tomorrow's reality.
Professor Adrian Raine was a contributor to BBC Two's If... We Could Stop The Violence, broadcast on Wednesday, 22 December 2004, at 2100 GMT.