LAST week, the US Congress passed a bill requiring TV manufacturers to install - computer chips in new TV sets that would allow parents to block shows they consider too violent for their children. Should Irish parents and legislators be demanding the same measures?
The answer is probably "yes". Yet more evidence that TV violence leads directly to criminal behaviour has come in a major new US study on the issue. It concluded that TV violence puts people at risk of committing violent crimes in the same way that cigarette smoking puts them at risk of lung cancer.
Just as not all who smoke will get lung cancer, not everyone who watches violent TV programmes will develop violent behaviour. But many will, particularly young people with other risk factors such as low socio economic status and access to weapons.
The National Television Violence Study, a survey of television programmes and of all known research on TV violence and behaviour, was conducted by four US universities and Mediascope, a non profit organisation that works with the entertainment industry on social issues. TV programmes which depict perpetrators of violence getting away unpunished most of the time are teaching violent behaviour, it said. Such programmes are also desensitising viewers to the harmful consequences of violence because violent acts are so often portrayed as painless and even humorous.
So that whether viewers actually behave violently or not, they still may react dispassionately to the suffering of others.
Mr Joel Federman, director of research for Mediascope, said the study did not mean that glamorised television violence caused all violence in American society but that it was a "significant part of the problem".
The study found that perpetrators go unpunished in 73 percent of all violent scenes on television, while negative consequences of violence are often not portrayed. Fifty eight per cent of violent portrayals do not show the victim feeling pain and 39 per cent are portrayed in humorous terms.
As if to show just how complex the relationship between environment and violent behaviour is, another US study has found that lead pollution can lead to bad behaviour in children.
Dr Herbert Needelman, a psychiatrist at the University of Pittsburgh, surveyed 11 year old boys with high levels of lead in their blood. These boys were reported by their parents and teachers to be more aggressive and they also had higher delinquent scores than boys with low lead levels, he wrote in the Journal of the American Medical Association.