“There is no question kids watch too much television at all ages,” says Dr. Dimitri Christakis, lead author and director of the Center for Child Health, Behavior and Development
at Seattle Children’s Research Institute. “Part of the message is not just about turning off the television but about changing the channel.”

Kids are sponges who absorb their surroundings; it’s how they learn to develop the proper behaviors and responses to social situations. And they are not only parroting their parents and other family members, but mimicking behaviors they see on television or in movies as well. So Christakis, who has conducted extensive research on the effects of screen time on child development, explored ways to influence what shows children watch so that they’re more apt to imitate quality conduct. “We’ve known for decades that kids imitate what they see on TV,” he says. “They imitate good behaviors and they imitate bad behaviors.”

In the study, he and his colleagues tracked 617 families with kids between the ages of 3 and 5. Half of the families agreed to go on a media “diet” and swap programming with more aggressive and violent content for educational, prosocial shows that encourage sharing, kindness and respect, like Dora the Explorer, which teaches how to resolve conflicts, and Sesame Street, which models tolerance for diversity. The other families did not change their children’s viewing choices.

To help parents in the first group to choose appropriate shows, they received a program guide that highlighted prosocial content and learned how to block out violent programming. (The parents were so delighted with the guidance that many asked to continue receiving program guides even after the study ended.) They were also urged to watch alongside their kids. The researchers tracked what the children watched and also measured their behavior with standard tests of aggressiveness and sharing responses six months and a year into the study.

At both testing periods, the children in the first group watched less aggressive programming than they did at the beginning of the study compared with children in the control group. Both groups of kids upped their screen time a bit, but the first group saw more quality programs while the control group spent even more time watching violent shows.

Six months after the study began, the children who increased their prosocial viewing acted less aggressively and showed more sharing and respectful behaviors compared with the control group. They were more apt to compromise and cooperate than children who didn’t change their viewing content, and the effects persisted for the entire year that the study lasted. “There is a connection between what children watch, not just in terms of violence but in terms of improved behavior,” says Christakis, who is also a professor of pediatrics at the University of Washington.

Who got the biggest boost in behavior? Low-income boys. “They derived the greatest benefit, which is interesting because they are most at risk of being victims and perpetrators of aggression,” he says.

In the study, published in the journal Pediatrics, the researchers analyzed data from 217 African-American mother and infant pairs from the Infant Care and Risk of Obesity Study. At 3, 6, 9, 12, and 18 months after birth, the infants’ mothers reported on their babies’ temperament—how fussy or complacent they were—as well as their own TV viewing habits, including how long the TV was on during the day and how often they fed their babies while watching TV. Overall, mothers spent a significant amount of time watching television, and reported that they spent quite a bit of time feeding their infants in front of the TV as well. Infants just 3 months old were exposed to an average of nearly three hours of TV or videos daily, and nearly 40% of the youngsters were exposed to three hours of TV every day by the time they were a year old.

More active and fussier infants were more likely to spend extended periods of time in front of the TV. The exposure was also higher among obese mothers, especially those with the fussier kids, leading the researchers to suggest that the television may serve as an easy entertainment strategy.

The scientists were also able to find some factors that contribute to fewer hours in front of the screen, however. Moms with a high school diploma or any additional education were less likely to have TVs in their infants’ room, and less likely to keep the television on during meals.

“In the last decade or so there has been a lot of attention paid to parenting style and care giving. One component has to do with feeding and focus placed on the feeding environment,” says Margaret E. Bentley, Associate Dean of Global Health at the University of North Carolina at Chapel Hill’s Gillings School of Global Public Health and the principal investigator of the study. “Half of the time, infants are being fed with the television on, which is a feeding strategy we do not recommend.”

Eating in front of the television can lead to unhealthy dining habits that linger into childhood and adulthood, Bentley and her colleagues say, since mothers feeding infants while watching TV might be distracted and not as alert to subtle cues babies send when they feel full, which can lead to overfeeding.

The iPad has only been around only since 2010, so there hasn’t been enough time to observe its long-term effects on kids, according to Michael Rich, director of the Center on Media and Child Health at Children’s Hospital in Boston.

Rich, who runs the online advice column Ask the Mediatrician, says that apps on iPads and smartphones are limited as teaching tools since they typically focus on one type of learning — “skills and drills,” which teach children to correctly identify the ABCs or to moo when they see a cow on the screen.

“What’s more important at this age is learning how to learn rather than mimicking something,” Rich says.

Moreover, studies show that kids don’t learn anything substantial, such as language, from screens — television, iPads, computers — until 30 months of age. The American Academy of Pediatrics recommends that parents hold off on any form of screen time until their children are 2.

A 2004 study in the journal Pediatrics showed that children exposed to television at ages 1 and 3 had decreased attention spans at age 7. It’s a bit of a chicken-and-egg question, though.

“You can see how a kid who already has difficulty paying attention is put in front of the television to chill him out,” Rich says. “It becomes a self-fulfilling prophecy.”

“Specifically, youngsters ages 5 to 18 who had TVs in their rooms were up to 2.5 times more likely than others to have bigger waists and more fat mass. Those who watched TV more than five hours a day were at twice the risk for fat around their internal organs, a dangerous precursor for disease.

“It’s really troubling to see these kids with fat around their heart and liver,” said Amanda Staiano, a scientist with the Pennington Biomedical Research Center in Baton Rouge, La.

Staiano and her colleagues knew that previous studies had shown a link among bedroom TVs, longer TV viewing and being overweight or obese, which affects two-thirds of U.S. youth. But in a country where 70 percent of kids have TVs in their rooms, according to a 2010 study, Staiano said they wanted to understand exactly where the kids were adding fat, and whether they were at risk for conditions such as heart disease and diabetes.

“We wanted to see kind of a more precise relationship between TV and health,” said Stainao, who studied 369 children and teens in Louisiana. Her findings are reported in the American Journal of Preventive Medicine.

They took the kids’ height, weight and waist measurements, logged their blood pressure, analyzed their blood and examined the fat deposits in their bodies using special scanners, among other exams.

Nearly 66 percent of the young people in the study had TVs in their rooms and about a third watched at least five hours of TV a day. There wasn’t a distinction by age, so even the youngest kids — 5-year-olds — had their own TVs, Staiano said.

Those with bedroom TVs had the higher odds for being in the top tiers of kids with extra belly fat, bigger waists, greater risk of heart disease and diabetes and elevated triglycerides, or fat in their bloodstream.

While Stainano’s study couldn’t say whether bedroom TV and long hours in front of the screen actually causes the extra fat and disease risk, it renews the debate about whether TVs should be allowed in kids’ rooms at all.

The American Academy of Pediatrics frowns on the practice, saying children’s TV viewing should be limited to less than two hours a day, ideally in a central location with parents watching, too.”

According to a nationwide study, a much bigger proportion of kids’ TV exposure comes indirectly, from television that’s on in the background while they’re doing other activities.

The average child between the ages of 8 months and 8 years absorbs nearly four hours of this so-called background or “secondhand” TV each day, the study found. And this indirect exposure, by detracting from play, homework, and family time, may have possible consequences for kids’ well-being.

This is the first study to quantify background television in children, and the high number is “surprising,” says lead author Matthew Lapierre, an assistant professor of communication studies at the University of North Carolina Wilmington.

“From a research perspective, I would be very concerned,” Lapierre says. “I think (background TV) is something that researchers need to spend more attention to, to understand and unpack.”