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Technology, like anything else, must be used in moderation for kids, according to a new study from the National Institutes of Health (NIH). The Adolescent Brain Cognitive Development (ABCD) Study suggests that excessive screen time is changing the physical structure of children's brains.

The study is still in the preliminary stages: NIH just completed enrollment, and for the next 10 years, scientists will track more than 11,000 children aged nine to 10 years old. However, scientists have already drafted a few hypotheses. Brain scans of 4,500 children found that those participating in more than seven hours of daily screen time showed "premature thinning of the brain cortex."

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The cortex helps process information from the five senses, according to Dr. Gaya Dowling, the NIH study director. Typically, the cortex thins later in life, Dowling said, but it's now happening sooner.

"We don't know if it's being caused by the screen time. We don't know yet if it's a bad thing," Dowling told CBS News.

Other early results of the ABCD study found that children who are exposed to more than two hours of daily screen time score lower on language and thinking tests.

Dr. Dimitri Christakis, who authored the American Academy of Pediatrics' most recent guidelines for screen time, suggested that children aren't able to transfer the skills they've learned in 2D to 3D.

Christakis told CBS News that parents should avoid digital media use, except maybe video chatting, for children younger than 18-24 months.

"If you're concerned about your teenager being addicted to their iPhone, your infant is much more vulnerable and using the exact same device," Christakis said.

The ABCD study will examine how screen time impacts health behaviors, cognitive and brain development, the risk of or resilience against substance abuse and mental illness, and more.

The NIH said in a press release that the first batch of data will release early next year.

Setting screen time boundaries is a big challenge that parents face today. Dozens of apps designed to help with cognitive development, parenting, and screens are increasingly used in schools and for homework.

It's not likely that the world will revert to paper and pencil, regardless of these study results. But perhaps having a better understanding of potential negative effects on children can raise awareness for parents and schools.

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  1. The National Institutes of Health just completed enrollment for the Adolescent Brain Cognitive Development study. For the next 10 years, scientists will keep track of more than 11,000 children aged nine to 10 years old.
  2. Early results of the study suggest that kids who have more than seven hours of screen time per day had premature thinning in their cortexes. Kids who had more than two hours per day scored lower on thinking and language tests.

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Shelby is an Associate Writer for CNET's She served as Editor in Chief for the Louisville Cardinal newspaper at the University of Louisville. She interned as Creative Non-Fiction Editor for Miracle Monocle literary magazine. Her work appears in Glass Mountain Magazine, Bookends Review, Soundings East, and on Her cat, Puck, is the best cat ever.