The roughly 40% increase in attention problems among serious TV viewers was observed in boys and girls, and was completely independent of whether a analysis of attention deficit/hyperactivity disorder was made before adolescence.
Young children often are mesmerized by the TV screen, says study leader Dimitri Christakis, a pediatrician at Children's Hospital and Regional Medical Center in Seattle. The potential link between watching TV and attention problems is a huge concern because so many infants and toddlers are watch television, he says.
The children aged 5 to 11 watched an average of 2.05 hours of weekday television. From age 13 to 15, time spent in front of the tube rose to an average of 3.1 hours a day.
"Those who watched more than two hours, and particularly those who watched more than three hours, of television per day during childhood had above-average symptoms of attention problems in adolescence," Carl Landhuis of the University of Otago in Dunedin wrote in his report, published in the journal Pediatrics.
Frequent TV viewers in early childhood were most likely to score in the highest 10% for concentration problems, impulsiveness and restlessness. Scoring within that 10% doesn't mean a child has attention deficit hyperactivity disorder (ADHD), but many would get it, and the others could face huge learning troubles, Christakis says.
Every additional hour of watching TV increased a child's odds of having attention problems by about 10%. Kids watching about three hours a day were 30% more likely to have attention trouble than those not watching television. The researchers accounted for many factors beside television that might predict problems concentrating, but the TV-attention link remained.
Young children who view a lot of television were more likely to carry on the habit as they got older, but even if they didn't the damage was done, the report said.
"This suggests that the effects of childhood viewing on attention may be long lasting," Landhuis wrote.
Landhuis offered several possible explanations for the association.
One was that the rapid scene changes common to many TV programs may over stimulate the developing brain of a young child, and could make reality seem lackluster by comparison.
"Hence, children who watch a lot of television may become less tolerant of slower-paced and more mundane tasks, such as school work," he wrote.
It was also probable that TV viewing may supplant other activities that promote concentration, such as reading, games, sports and play, he said. The lack of participation inherent in TV watching might also condition children when it comes to other activities.
The change isn't necessarily bad, Los Angeles media psychologist Stuart Fischoff says. As media exposure grows, "these kids could be expressing "the new brain." They could be an advance guard that suggests we may need new ways of teaching children exposed to a lot of media stimulation."
But some experts are concerned. "This should be a wake-up call that we need to take a closer look at how early media use affects children," says Vicky Rideout of the Kaiser Family Foundation. "We know hardly anything about it."
