Too much time in front of the tube as a two-year-old can predict some negative consequences at the age of 10, a new study suggests.
Researchers studied more than 1,300 children in Quebec and found that higher TV exposure as toddlers corresponded to less achievement in math, an increase in being victimized by classmates and less physical activity at age 10.
The children also had a higher likelihood of consuming more junk food and soft drinks and of having a higher body mass index, according to the study published Monday in the Archives of Pediatrics & Adolescent Medicine.
Parents reported their kids' viewing habits at age 29 months and at 53 months as part of the Quebec Longitudinal Study of Child Development. Teachers were asked to evaluate the students' academic, psychosocial and health habits, and body mass index was measured at 10 years old.
Researcher Linda Pagani, a psychosocial professor at the Universite de Montreal, says the bottom line is that the American Academy of Pediatrics recommends no TV from birth to age two, and no more than two hours a day after that.
If parents aren't following these guidelines, then their kids are missing out on other opportunities, she said.
"There's only 24 hours in the day, and the early childhood period is a period of brain expansion," explained Pagani, who also works at the Sainte-Justine University Hospital Research Centre.
"But that brain expansion occurs in the context of a lot of interaction with one's environment - playing, talking, interacting, making intellectual effort - because your brain is like a muscle, and if you don't use it, it's less fit for more muscular activity later on."
But Deborah Linebarger, director of the Children's Media Lab at the University of Pennsylvania, says lumping all television together is not the best way to fully understand later developmental effects.
"By lumping it all together, any positive gains associated with educational content are typically masked," she said in an e-mail from Denver, where's she attending a conference.
"Early TV use becomes demonized and parents who let their infants and toddlers watch this content are (potentially seen as) 'bad' parents."
She said her research indicates that watching educational content when in preschool predicts higher grades in high school, better academic self-concepts and more leisure book reading.
But she said watching child-directed but age-inappropriate content predicts poorer language and less or no learning.
Dimitri Christakis, director of the Center for Child Health, Behavior and Development at Seattle Children's Hospital Research Institute, said the new study by Pagani is further evidence of the real potential harm associated with TV viewing.
But he, too, said there's a problem in viewing it monolithically.
"We know that for kids a lot depends not just on how much they're watching, but what they're watching," he said from Vancouver.
"And for some kids, particularly given that they're watching the wrong kinds of shows, the effects are actually probably much worse than what they found. But for other kids, who might be watching the appropriate types of shows, the effects are probably much less bad, and maybe even good."
Christakis was not surprised by association between greater TV viewing as a youngster and higher consumption of junk food and soft drinks at an older age.
"We know from a great number of studies that children are incredibly influenced by the advertising they see. In fact, preschool children are more influenced by ads than are older children," he said.
The new study did not distinguish between direct viewing and television in the background.
Linebarger said that experiments show that when a television is on in the background, infants and toddlers play episodes are shorter and less cognitively complex.
And Christakis said a study a few months ago audiotaped kids under age four who wore a vest with a digital microphone recording everything they could hear, and what they said.
If they heard a television, they spoke less and were spoken to less, he said, and that included when a television was on in the background.
Pagani said she recommends that parents follow the pediatrics academy guidelines.
"A lot of parents are completely unaware of those guidelines. They assume that television is harmless. They treat it like a coffee table."