Children under the age of two should not be allowed to watch any TV, according to the authors of a new US study.
The study, conducted by a team in Seattle, found that each hour spent in front of a TV increased by 10 per cent the chances of a child developing attention problems.
Researchers tested over 1,000 children at the ages one, three and seven. The children's TV viewing habits were monitored at ages one and three and their parents were asked when the children were aged seven to rate their child's behaviour on a scale similar to that used to diagnose attention deficit disorders.
The children who watched the most TV were found to be more likely to rank within the top 10 per cent of those having concentration problems, impulsiveness, restlessness and being easily confused. "This study suggests that there is a significant and important association between early exposure to television and subsequent attention problems," the study's lead researcher Dr Dimitri Christakis said.
He said the new-born brain develops very rapidly during the first two to three years of life and children who were exposed to unrealistic levels of simulation at a young age continued to expect this in later life, leading to difficulty dealing with the slower pace of school and homework.
Another of the authors Dr Frederick Zimmerman, said it was impossible to say what a safe level of TV viewing would be for children aged one to three.