How does screen time affect kids’ brains? The first results of a landmark study are alarming.

The National Institutes of Health recently began a $300-million study to examine the effects of screen time on developing brains.

  • The study uses MRI scans to track the changes in the brains of children who use screens at varying amounts.
  • Early results revealed that kids who use screens for more than 7 hours per day show physical changes to the brain in the form of premature thinning of the cortex.
  • It will likely be decades before scientists truly understand how smartphones and other technologies affect the brain.

How does screen time affect the developing brains of young kids?

That's the big question behind a $300-million study conducted by the National Institutes of Health that's using MRI scans to examine changes in brain structure among children who use smartphones and other screen devices. The first batch of results from the study, which was highlighted by CBS's 60 Minutes on Sunday, shows that kids who spent more than two hours per day on screens scored lower on language and thinking tests.

Alarmingly, kids who spent more than seven hours per day on electronic devices showed premature thinning of the cortex, which Dr. Gaya Dowling of the National Institutes of Health described as a "maturational process" that typically happens later in development.

"We don't know if it's being caused by the screen time," said Dowling. "We don't know yet if it's a bad thing. It won't be until we follow them over time that we will see if there are outcomes that are associated with the differences that we're seeing in this single snapshot."

It will take a few years to get answers to some of the questions raised by the study. However, the most interesting results will likely come decades from now, when researchers can see the long-term effects of technology use on the brain. Dr. Dimitri Christakis of Seattle Children's Hospital, the lead author of the American Academy of Pediatrics' most recent guidelines for screen time, told CBS he's concerned about this uncertainty.

"In many ways, the concern that investigators like I have is that we're sort of in the midst of a natural kind of uncontrolled experiment on the next generation of children," Christakis said.

Most kids say they spend too much time on smartphones

American teenagers now spend more than four and a half hours on their phones per day, and that's not even necessarily counting additional time spent playing video games, watching TV or using the computer. It's no surprise that a generation of kids who'd be hard pressed to remember a time without smartphones have made them a big part of daily life—the iPhone came out in 2007, after all, so kids born after 1995 entered adolescence with touchscreens in hand.

Many kids are themselves concerned. A recent survey from the Pew Research Center found that 54 percent of U.S. teens said they spend too much time on their phones, and 60 percent of them consider spending too much time online to be a "major problem." The data seem to back that up, with today's teenagers reporting lower levels of drinking, sex and drug use, yet higher levels of depression and loneliness.

This year, Facebook, Apple and Instagram began offering tools to help users monitor and reduce their screen time, including features that let users set time limits and see how their screen time is allocated across different apps. Some of these features are designed to help parents restrict their children's screen time.

Of course, the best solution might be to wait to give your kid a phone until it's necessary. The American Academy of Pediatrics' recommends for "children younger than 18 months, avoid use of screen media other than video-chatting," and that parents "of children 18 to 24 months of age who want to introduce digital media should choose high-quality programming, and watch it with their children to help them understand what they're seeing."

​An unprecedented technology

Tristan Harris, a former Google manager who's spoken publicly on how Silicon Valley is intentionally making smart devices as addictive as possible, told 60 Minutes that some parents are under the false impression that smartphone use is analogous to chatting on the phone in past decades.

"... there's a narrative that, oh, I guess they're just doing this like we used to gossip on the phone, but what this misses is that your telephone in the 1970s didn't have a thousand engineers on the other side of the telephone who were redesigning it to work with other telephones and then updating the way your telephone worked every day to be more and more persuasive."

Tristan Harris: Your brain is vulnerable to hacking

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An organism found in dirt may lead to an anxiety vaccine, say scientists

Can dirt help us fight off stress? Groundbreaking new research shows how.

University of Colorado Boulder
Surprising Science
  • New research identifies a bacterium that helps block anxiety.
  • Scientists say this can lead to drugs for first responders and soldiers, preventing PTSD and other mental issues.
  • The finding builds on the hygiene hypothesis, first proposed in 1989.

Are modern societies trying too hard to be clean, at the detriment to public health? Scientists discovered that a microorganism living in dirt can actually be good for us, potentially helping the body to fight off stress. Harnessing its powers can lead to a "stress vaccine".

Researchers at the University of Colorado Boulder found that the fatty 10(Z)-hexadecenoic acid from the soil-residing bacterium Mycobacterium vaccae aids immune cells in blocking pathways that increase inflammation and the ability to combat stress.

The study's senior author and Integrative Physiology Professor Christopher Lowry described this fat as "one of the main ingredients" in the "special sauce" that causes the beneficial effects of the bacterium.

The finding goes hand in hand with the "hygiene hypothesis," initially proposed in 1989 by the British scientist David Strachan. He maintained that our generally sterile modern world prevents children from being exposed to certain microorganisms, resulting in compromised immune systems and greater incidences of asthma and allergies.

Contemporary research fine-tuned the hypothesis, finding that not interacting with so-called "old friends" or helpful microbes in the soil and the environment, rather than the ones that cause illnesses, is what's detrimental. In particular, our mental health could be at stake.

"The idea is that as humans have moved away from farms and an agricultural or hunter-gatherer existence into cities, we have lost contact with organisms that served to regulate our immune system and suppress inappropriate inflammation," explained Lowry. "That has put us at higher risk for inflammatory disease and stress-related psychiatric disorders."

University of Colorado Boulder

Christopher Lowry

This is not the first study on the subject from Lowry, who published previous work showing the connection between being exposed to healthy bacteria and mental health. He found that being raised with animals and dust in a rural environment helps children develop more stress-proof immune systems. Such kids were also likely to be less at risk for mental illnesses than people living in the city without pets.

Lowry's other work also pointed out that the soil-based bacterium Mycobacterium vaccae acts like an antidepressant when injected into rodents. It alters their behavior and has lasting anti-inflammatory effects on the brain, according to the press release from the University of Colorado Boulder. Prolonged inflammation can lead to such stress-related disorders as PTSD.

The new study from Lowry and his team identified why that worked by pinpointing the specific fatty acid responsible. They showed that when the 10(Z)-hexadecenoic acid gets into cells, it works like a lock, attaching itself to the peroxisome proliferator-activated receptor (PPAR). This allows it to block a number of key pathways responsible for inflammation. Pre-treating the cells with the acid (or lipid) made them withstand inflammation better.

Lowry thinks this understanding can lead to creating a "stress vaccine" that can be given to people in high-stress jobs, like first responders or soldiers. The vaccine can prevent the psychological effects of stress.

What's more, this friendly bacterium is not the only potentially helpful organism we can find in soil.

"This is just one strain of one species of one type of bacterium that is found in the soil but there are millions of other strains in soils," said Lowry. "We are just beginning to see the tip of the iceberg in terms of identifying the mechanisms through which they have evolved to keep us healthy. It should inspire awe in all of us."

Check out the study published in the journal Psychopharmacology.