This article originally appeared on RealSimple.com.
Getting lots of sleep is essential for the health and development of babies and toddlers. But a new study published in Scientific Reports suggests that young children who use touchscreen devices, like smartphones and tablets, get slightly less shuteye than those who don’t.
The news isn’t all bad for screen-toting toddlers, though: Although they got less sleep, they also developed fine-motor skills sooner than screen-free kids. So for now, the study authors say, the jury is still out.
The new study, conducted by researchers at Birkbeck University of London, involved 715 parents who answered online questionnaires about their children’s daily exposure to television and touchscreens, as well as their sleep patterns—how long they slept at night and during the day, how long it took them to fall asleep, and how often they woke up throughout the night.
The researchers then analyzed the parents’ responses, using a model that controlled for the mother’s education level and the children’s age (6 to 36 months), gender, and television exposure.
Touchscreen use was common among these kids: Overall, 75 percent of the children used touchscreens on a daily basis—including 51 percent of babies 6 to 11 months old, and 92 percent of toddlers 25 to 36 months. On average, children in the study used touchscreens for about 25 minutes a day.
But the children who used touchscreens, the results suggested, took longer to fall asleep and also slept less overall: Every hour of screen use was linked to 15 minutes less sleep in a 24-hour period—about 26 minutes less at night and 11 minutes more during the day. Touchscreen use did not seem to affect the number of times kids woke during the night.
“One surprising finding was that despite sleeping more on average during the day, infants and toddlers who spend more time on a touchscreen still spend less overall time sleeping,” says co-author Celeste Cheung, a research fellow at Birkbeck. “Thus, they were not able to ‘catch up’ with their sleep during the day.”
There are several reasons why touchscreens might affect children’s sleep, the authors wrote in their paper: Playing with electronic media could directly displace the time that they have available for sleep, leading to later bedtimes, or the content may arouse and excite them so it’s more difficult fall asleep.
The bright light from the screens can also suppress melatonin and affect circadian timing, a theory that applies to people of all ages. Or, they add, it could be that children with certain traits—like hyperactivity—are more likely to sleep less and also seek out touchscreen use.
This appears to be the first report to link touchscreens and sleep problems in infants and toddlers, say the study authors, although the findings are consistent with research in older children, as well as studies on television exposure in this age group. More research is needed, they add, to determine a cause-and-effect relationship and to tell whether touchscreen use actually has an effect on cognitive development.
They say it’s too early to suggest banning touchscreens entirely from children under 3, especially because their previous research has found some advantages: In the same group of toddlers, those who actively use touchscreens—swiping and playing games, rather than simply watching them—reached motor-skill milestones earlier than those who didn’t use them at all.
Earlier this year, the American Academy of Pediatrics recommended that children under 18 months should have no exposure to digital screens, and that children ages 2 to 5 should spend no more than an hour a day watching television or using a touchscreen device.
Dr. Cheung says that, because the long-term effects of touchscreen-related sleep loss are not yet known, her team is “not in the position to either agree or disagree with AAP’s recommendations.” For now, she says, “parents should not be overly concerned, but be aware of the potential impact of touchscreen devices—both positive and negative.