There have been multiple studies that warn parents of the dangers off too much screen time, both for younger kids with developing brains and older kids dealing with the quagmire of social media.

If you’ve got littles, though, you might be interested to learn how too much of it can lead to developmental delays.

This recent study, which was published in the Journal of the American Medical Association of Pediatrics, suggests that infants that get screen time experience delays in real-life motor skills.

They typically develop those by watching the people around them.

The parents of more than 7000 kids took part in the study, and answered a single question: “On a typical day, how many hours do you allow your children to watch TV, DVDs, video games, internet games (including mobile phones and tablets), etc?”

Scientists tracked data and results from infancy (under a year) until the children were 4, and found that the kids who watched more screens experienced delays in development like gross and fine motor skills, language ability, and social skills.

Kids who had up to four hours of screen time a day before they were 2 were three times more likely to experience communication and problem-solving delays.

Those who had more than 4 hours were more than 5x more likely to develop those same delays.

Dr. John Hutton, an associate professor of general and community pediatrics who was not involved with they study, spoke to CNN about the results.

“They may hear a lot of words, but they’re not practicing saying a lot of words or having a lot of that back-and-forth interaction.”

Play and social interaction are important to the development of these social and motor skills, and parents who use screens to distract kids from being upset, bored, or fussy are robbing them of important lessons.

“Longer term, one of the real goals is for kids just to be able to sit quietly in their own thoughts. When they’re allowed to be a little bit bored for a second, they get a little uncomfortable, but then they’re like ‘OK, I want to make myself more comfortable.’ And that’s how creativity happens.”

That advice goes for adults, too.

In case you were wondering.