Do Screens Really Stunt Kids’ Brains?

A new study links higher screen time with lower white matter in the brain. But don’t freak out. Here’s what you should know.

Credit: Jurgita Vaicikeviciene / EyeEm / Getty Images

AA new study links young children’s screen time with changes in the brain and slower language development. But parents, before you freak out, take note: Experts — including the author of the study — say it’s probably because of what activities the screen time is replacing instead of the iPads themselves.

The study, published in JAMA Pediatrics, tested 47 children between the ages of three and five on their language and budding reading skills. It also measured the integrity of white matter tracts — bundles of nerve fibers that connect different brain regions — using a special type of MRI scan called diffusion tensor imaging (DTI).

While the kids were busy in the scanner, their parents filled out the ScreenQ, a questionnaire the researchers developed to assess whether the child’s screen use was in-line with the American Academy of Pediatrics’ current recommendations: “For children ages 2 to 5 years, limit screen use to 1 hour per day of high-quality programs. Parents should co-view media with children to help them understand what they are seeing and apply it to the world around them.”

The questionnaire asked not only about the child’s amount of screen use, but also their access to screens (TV in the bedroom, having their own iPad), what type of content they consumed, and whether parents watched with their child. A zero on the measure indicates perfect adherence with the guidelines, while the highest score, 26, would mean entirely ignoring the recommendations. The average score in the study was nine, indicating families “were missing the boat on a good number of things, but they weren’t completely off the chart,” says John Hutton, a pediatrician at Cincinnati Children’s Hospital, who led the research.

The researchers found that higher scores on the ScreenQ corresponded to lower white matter organization and myelination — a fatty substance that coats the nerve fibers so that electrical signals travel more efficiently through the brain. This effect was especially pronounced in three nerve tracts that connect regions related to reading, language, imagination, and mental processing speed.

Daniel Anderson, a professor emeritus in psychological and brain sciences at the University of Massachusetts Amherst, who was not involved in the study, says that while it’s easy to jump to the conclusion that screen time is bad for kids, there are alternative explanations for the result. “We know that real-time interactions with adult caretakers are really important for language development in young children, and we know that screens can’t fill that gap,” he says. “What they may have found simply is that screens are a proxy for minimal parent-child interactions.”

“I think a lot of these discussions presume that the thing we would be doing with our kids if they weren’t watching TV is somehow engaging in high IQ interactions with them.”

Besides time with parents, screens may also be displacing time spent doing other more cognitively stimulating activities, such as reading, playing sports, or studying music. Fortunately, Anderson says, as long as kids spend some time on those other activities, any impact of screen time will be overcome.

Hutton agrees with Anderson’s interpretation. “Probably the biggest driver was the potential that more screen use interfered with more parent-child or child-real world interactions that may have been more developmentally constructive,” he says. “There’s the idea of screen time getting in the way of activities that would have been more beneficial. That would be my bet.”

A second finding of the study appears to support this theory. The researchers saw a correlation between high screen use and low scores on the three cognitive tests, but that effect disappeared when they controlled the analysis for household income. This shift hints at some of the other factors that might play a role in the relationship between screen time and cognitive development. Research has shown that parents with higher incomes spend more time talking and reading to their children, which is strongly associated with higher literacy scores. In low-income households where parents may have to work several jobs, there might be less time for bedtime stories or fewer opportunities for extracurricular activities like dance classes or music lessons. TV could end up replacing that time.

“I think if the choice is to have your kid sit in front of the screen or have you read books to them or play an intellectual game or go for a hike, maybe those other things are better,” says Emily Oster, author of Cribsheet: A Data-Driven Guide to Better, More Relaxed Parenting, from Birth to Preschool. “But I think a lot of these discussions presume that the thing we would be doing with our kids if they weren’t watching TV is somehow heavily engaging in high IQ interactions with them, as opposed to recognizing that sometimes it’s good for everybody to have a break, and that’s part of what makes for good parenting.”

Oster’s advice: “Don’t freak out, and try to spend some time with your kids.”

Health and science writer • PhD in 🧠 • Words in Scientific American, STAT, The Atlantic, The Guardian • Award-winning Covid-19 coverage for Elemental

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