The most-cited study on the cognitive effects of TV on young children was conducted by a team led by Dimitri Christakis, a pediatrician and director of the Center for Child Health, Behavior, and Development at Seattle Children’s Hospital. The paper, published in 2004, examined the relationship between the number of hours of television that a child watched at ages 1 and 3 and the child’s score on a well-known diagnostic test of attention problems at age 7. The study found a significant relationship between these variables: The more TV that you watch as a toddler, the more likely you’ll have attention-related problems as a first-grader. The researchers reported that this relationship held up even after they controlled for various complicating factors, including parental substance abuse and socioeconomic status.
Yet there are a few shortcomings with this study that make its findings difficult to apply to my life, and probably yours as well. First, the Seattle study only tells you what happens to your kid if he watches lots of TV. On average, the 1,300 1-year-olds in the study watched 2.2 hours of television a day. The authors say that for every three additional daily hours of television that a kid watches at age 1, his chance of developing attention problems by age 7 increases by 28 percent. The study says nothing about whether watching a lot less television would be bad for your child, however. What’s more, it doesn’t look at what kids were watching—were children who watched “educational” TV less likely to develop problems than kids who watched MTV? Finally, the study can’t establish a causal relationship between TV viewing and attention problems. This seems important: Some parents were letting their kids watch five or more hours of television a day. It stands to reason that these weren’t great parents—so maybe it was something about their parenting skills, and not the boob tube itself, that caused these kids to develop problems.
Christakis and other researchers have conducted several follow-up studies that seek to address some of these problems, and much of this research presents a less alarming story. In a paper published in 2009, Marie Evans Schmidt, a researcher at the Center on Media and Child Health at Children’s Hospital Boston, looked at a group of children who watched slightly less TV than those in Christakis’ study. Schmidt also took into account many environmental factors that could shed some light on the effects that parents played in a child’s life, including whether and for how long a child had been breast-fed and the amount he slept each night. Instead of focusing on attention problems, Schmidt’s team analyzed the effects of TV on the child’s visual and motor skills. They found something remarkable: There was no effect. After controlling for environmental factors, each additional hour of television that a child watches at or before age 2 is not associated with any change in test scores at age 3.
Schmidt acknowledges a shortcoming in her study—she stopped watching these kids at 3, and it’s possible that their test scores may have been affected later in life. But a 2007 study by Christakis suggests there’s even less reason to be paranoid about TV. This time, researchers looked at what kinds of shows kids watched. They found that toddlers who watched entertainment shows saw an increased risk of developing attention-related problems five years later (and an even greater risk if those shows were violent). Kids who watched “educational” TV shows exhibited no greater risk.
What is educational TV? Christakis’ team looked at several shows, including Barney, Sesame Street, Winnie the Pooh, and Blue’s Clues. All of these programs have a single thing in common—they’re all (agonizingly) slow. They feature long scenes, they often deliberately pause the action to let kids catch up, and they shy away from wild camera movements and garish colors. Christakis says that fast-paced television shows trip your child’s “orienting response,” which is a reflex triggered by novel stimuli. That’s why your kid can’t resist watching cartoons: Every millisecond, there’s something new and colorful on the screen. Not only could this overstimulation cause attention-deficit problems over time, but there’s pretty good evidence that such shows immediately change kids’ behavior. Studies have shown that kids are more tolerant of delay and are more willing to pay attention right after watching Mister Rogers than after being parked in front of Batman or Power Rangers. In one recent study, kids who watched Spongebob scored far lower on a battery of tests than those who sat through a slow-paced educational show.
Christakis’ research suggests an escape hatch in the blanket prescription against TV: If you need to plop your kid in front of the tube, make sure you flip the channel to PBS (or the Republican presidential debate). There are some caveats here. Christakis points out that while educational TV isn’t detrimental, there’s no evidence that it’s beneficial for your child. The more time your baby spends watching Sesame Street, the less time he has to do other things that we know are good for him, like looking at picture books or playing with three-dimensional objects.
In general, Christakis says, babies’ exposure to TV is comparable to the effects of secondhand smoke. “We know for a fact that some exposure has a detrimental effect, and as a parent, you should try to minimize this exposure,” he says. “But that doesn’t mean that if you’re seated next to someone who’s smoking in a restaurant that you should grab your children and run. Ten minutes, 20 minutes, 30 minutes of exposure to secondhand smoke or to television isn’t going to cause your child any harm—it’s really much more about not making it a regular practice.”
I asked both Christakis and Schmidt about the many other screens that dominate our lives today, and neither could cite any research about the effects of these devices. Christakis pointed out that our computers, tablets, and phones often function as miniature TV sets. (Khalil loves the Wiggles’ videos on YouTube, for instance.) In that case, you’d expect these devices to have the same cognitive effect on kids.