The seeds of criminal and anti-social behaviour can be found in children as young as three, scientists have claimed.
More researchers believe that violent tendencies have a biological basis and that tests and brain imaging can pick them up in children.
They argue that, by predicting which children have the potential to be trouble, treatments could be introduced to keep them on the straight and narrow. If the tests are accurate enough then a form of screening could be introduced in the same way we test for some diseases.
The theories were put forward by two leading criminologists at the American Association for the Advancement of Science in Washington.
Prof Adrian Raine, a British criminologist, argued that abnormal physical brain make-up could be a cause of criminality, as well as helping to predict it.
His studies have shown that psychopaths and criminals have smaller areas of the brain such as the amygdala and prefrontal cortex, both of which regulate and control emotion and behaviour. He also believes that a lack of conditioning to fear punishment, which can be measured in toddlers before disruptive behaviour is apparent, could also be a strong indicator.
Dr Nathalie Fontaine, who also spoke at the conference, argued that children as young as four exhibited “callous unemotional traits” such as lack of guilt and empathy that could also suggest future bad behaviour. Linking these features with “conduct problems” such as throwing tantrums could be a strong way to predict who could be anti-social in later life.
Both speakers said that identifying these issues earlier could be important in stopping children from becoming criminals.
Dr Raine, a former Home Office psychologist who works at the University of Pennsylvania, said therapy could include counselling to counteract innate behavioural problems and boosting the brain with drugs or foods rich in Omega 3.
Dr Fontaine, from Indiana University, said the work showed that punishment did not necessarily work and that reinforcing positive behaviour rather than punishing bad might be the solution.
“If we could identify those children early enough, we could help them as well as their families,” she said.
Dr Fontaine used data from more than 9,000 twins from the Twins Early Development Study, a survey of twins born in England and Wales between 1994 and 1996. Assessments of callous unemotional traits and conduct problems were based on teacher questionnaires when the children were seven, nine and 12. Information was taken from parents when the children were as young as four.
She found there was a correlation between risk factors at a young age and bad behaviour at an older age.
Dr Raine said he acknowledged the ethical implications of treating children before they had done anything wrong, but argued that “biological” causes of crime could not be ignored.
“We could be ostriches and stick our heads in the sand but I believe we have to pursue the causes of crime at a biological and genetic level as well as at a social,” he said.