For teens, too much TV can impair learning later, study says

Those who watched at least three hours a day reported poor performance in school.

If your 14-year-old is sitting in front of the TV for hours a day, your concerns about your teenager's education may be borne out.

That's because watching three or more hours of television a day leads to poor homework completion, negative attitudes toward school, bad grades, and poor performance in college, according to a study published this week.

"We found a very clear correlation between higher levels of TV watching by 14-year-olds and subsequent attention and learning problems developed during the remainder of their years," says Jeffrey Johnson, lead author of the study in the Archives of Pediatrics and Adolescent Psychiatry.

"This is very persuasive evidence that confirms other large studies concluding that parents worried about their kids going to college and being successful beyond should make sure their teenagers are not watching too much TV," he adds.

Whether watching a lot of TV sharpens people's mental skills or shortens their attention spans, zaps energy, and fosters violent behavior has been the source of much debate over the years. Hundreds of studies have come down on both sides of the argument.

This one is considered valuable by many experts because it has followed 700 families for 19 years. The same people were interviewed at the ages of 14, 16, 22, and 33 in upstate New York.

"This is a well-executed study and is important because it looks at the possible effects of TV watching over such an extended period," says Thomas Crook, author of the book "The Memory Advantage: Improve Your Memory, Mood and Confidence Throughout Life" and chief executive officer of the Cognitive Research Corporation.

"The data goes back a very long way, [unlike] most of what comes out about TV and its purported effects. Other analyses are based on a kind of one-shot deal, whereas this assesses subjects again and again over many years," he adds.

Many see it as a wake-up call, including groups who are disinclined to agree with basic conclusions that TV is inherently a negative influence.

"This is a red flag that underscores that there is no doubt children have unbelievable access to and knowledge of media and that we need to make sure they are literate about its influences," says Robin Bronk, executive director of The Creative Coalition, a nonprofit public policy arm of the arts and entertainment industry. "I realize that as a parent I can't just leave my child in a candy store without supervision; they need to know how to digest the material they are exposed to."

Other experts are taking the findings to task for not considering other reasons why adolescents who watch large amounts TV have less academic success as they mature."I agree with the fundamental conclusion that it's not a good thing for kids to sit around and watch too much TV," says Daniel Howard, chair of the marketing department at Cox School of Business at Southern Methodist University in Dallas.

"But I would suggest that people not get too comfortable with the particular conclusion that TV is the monster. The root cause of a lot of these later developmental problems by TV watchers could be some other problem. The whole implication that if you stop TV viewing, that all of these other problems might go away is wrong," he adds.

Teenagers may also watch a lot of TV for other reasons. It can be a less expensive substitute for other entertainment, a particular issue for low-income families, says Karen Sternheimer, author of the book "It's Not the Media: The Truth about Pop Culture's Influence on Children." "Parents who are absent or not involved with their kids' education is also one of the great predictors of school failure," she says.

Others voice concern that the study may be a bit dated since it began before the proliferation of some modern media, include cable and satellite TV with some 700 channels.

"The world has changed a lot since they began asking questions at the beginning of this study," says Frank Farley, former president of the American Psychological Association. "The kind of media world that concerns parents today – the Internet explosion and iPods and all that – is not involved with this study. It has a kind of musty quality."

Although the study may not show a precise causal relationship between TV and later educational problems, it should sound the alarm for parents, says Thomas Demaria, vice president of behavioral mental health and substance abuse centers at the South Nassau Communities Hospital.

"TV itself may not lead directly to all the problems this study seems to claim, but allowing kids to watch it may take them away from other activities – such as reading or interacting with others or playing sports," says Dr. Demaria.