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How much screen time is too much? New research shows just how bad screens can be for kids' brains

A teenager messages a friend from her home in Orem, Utah, on Monday, Nov. 6, 2017.
A teenager messages a friend from her home in Orem, Utah, on Monday, Nov. 6, 2017.
Kristin Murphy, Deseret News

SALT LAKE CITY — The physical formation of kids' brains is being altered by smartphone, tablet and video game use, according to a new study from the National Institutes of Health.

Preliminary data from the Adolescent Brain Cognitive Development (ABCD) study, released earlier this month, show that children who reported more than two hours a day of screen time got lower scores on thinking and language tests.

In addition, MRI scans found significant physical differences in the brains of children who spent more than seven hours a day looking at screens. Most notably, those kids had prematurely thinning cortexes, the outermost layer of the brain responsible for processing sensory information like vision, hearing and touch, said study director Gaya Dowling, Ph.D., on CBS’ "60 Minutes."

"We don't know yet if it's a bad thing," Dowling said in the CBS interview earlier this month. The cortex typically thins as a child gets older, but the process is occuring sooner for kids who spend more time with phones and video games, Dowling said.

As parents become increasingly concerned about the time kids spend on devices and researchers debate whether social media is addictive, multiple studies, such as a 2017 study in the journal Clinical Psychological Science, have identified ties between screen time and poor mental health. But the ABCD study is the first to track the effect of screens on brain development throughout a person's entire adolescence.

In order to better understand how a child's experiences and biology interact to affect brain development — and ultimately, social, behavioral and health outcomes — researchers recruited more than 11,000 9- and 10-year-olds at 21 locations throughout the United States and plan to follow them into early adulthood. Recruitment of research subjects, including 2,100 young people who are twins or triplets, began in 2016 and ended earlier this year, according to the National Institutes of Health.

Researchers are using advanced neuroimaging to observe brain development in children throughout adolescence, while also tracking other factors like mental illness and substance use, the institute reported.

Data from the first 4,500 children enrolled in the $300 million study was released earlier this month. While early findings provide a glimpse into the short-term impact of screens on the brain, the long-term effects won’t be known for many years, Dowling told CBS. In 2019, anonymized data from the entire participant cohort will be made available to any researcher around the world, the group announced.

“We’ll be able to see not only how much time are they spending, how they perceive it impacting them, but also what are some of the outcomes,” said Dowling. “And that will get at the question of whether there’s addiction or not.”

Jean Twenge, psychology professor at San Diego State University and author of "iGen: Why Today's Super-Connected Kids Are Growing Up Less Rebellious, More Tolerant, Less Happy — and Completely Unprepared for Adulthood," said kids born after 1995 are the first to spend their whole adolescence in the "smartphone era."

"(These kids) spend more time online and less time with their friends in person. They also spend less time sleeping," Twenge told the Deseret News. She is happy to see more discussion in recent years about how to manage use of electronic devices.

Facebook and Instagram have introduced settings that allow users to monitor app use. For example, Instagram now shows users the average time spent on the app per day and lets people set a daily time limit and reminder that notifies them when they've reached their goal.

Apple also recently released a new suite of screen time tools. The features, part of iOS 12, appear under "Settings" on the iPhone and are designed to help users limit time spent on certain apps. The "Downtime" tool lets iPhone owners schedule times when only phone calls and certain apps are available for use.

Teens can take initiative and use these tools themselves, or parents can intervene with automated weekly reports and the ability to remotely schedule "downtime," essentially locking kids out of certain apps during meals or at bedtime.

These “digital wellness” features are part of a greater push by tech companies to mitigate the ways personal devices have been engineered to be addictive. Android’s own screen time tools are currently in development, Wired reported.

"A lot of parents, probably the majority I talk to, don't even realize those tools are available. And I wish they happened five years ago instead of now. But better late than never," Twenge said on "60 Minutes."

The new NIH study adds to a growing body of research on screen time and the brain. Other studies have linked excessive screen time with negative health outcomes, such as increasing obesity. Another recent study found teens who use electronic media at night are more likely to experience sleep disturbances and symptoms of depression.

Cutting back on screen time may reverse some of these negative effects. Researchers at the University of Pennsylvania found that when college students limited their social media use to less than 30 minutes a day, they reported feeling less lonely and depressed after just three weeks.

But the news about screens isn't all bad.

According to a new national survey by the Pew Research Center, 81 percent of teens feel more connected to their friends when they use social media, and 69 percent feel social media helps them interact with a more diverse group of people.

Ellen Selkie, adolescent medicine physician at the University of Michigan C.S. Mott Children’s Hospital, warns against thinking that “electronic devices are melting everyone’s brains.”

“It’s clear that there is an interplay between media and child development,” Selkie told Healthline, “but I don’t think it’s realistic to take away all electronic devices.”

Parents can also refer to the the American Academy of Pediatrics media guidelines, quoted here:

  • Avoid digital media use (except video-chatting) in children younger than 18 to 24 months.
  • For children ages 18 to 24 months, if you want to introduce digital media, choose high-quality programming and use media together with your child. Avoid solo media use in this age group.
  • For children ages 2 to 5, limit screen use to 1 hour per day of high-quality programming, coview with your children, help children understand what they are seeing, and help them apply what they learn to the world around them.
  • No screens 1 hour before bedtime, and remove devices from bedrooms before bed.

"Just as parents limit how late their kids can stay up and how much sugary food they eat, they should limit the amount of time children and teens spend with screens," Twenge told the Deseret News.

"Consider putting off getting your child a smartphone until they are ready for it — for most kids, not until 14 or later," she said. "And then use a parental control app to limit time on certain apps, and most importantly, shut the phone off at bedtime."