Study Shows Screen Time Changes White Matter in Children’s Brains

Maria Morioka, BSN, RN
November 11, 2019

A recent study published in the Journal of the American Medical Association (JAMA) of Pediatrics has found structural changes in critical areas of the brain in children exposed to high amounts of screen time.


Areas of the brain linked to language, cognition, and literacy were most affected. For families of young children, this news could change the way they allow children access to screen media.

Most parents have been there. It’s very tempting. A frayed, frustrated parent. A crying, angry child. And a smartphone with easy access to Peppa Pig. The promise a hours worth of quiet reprieve. What harm could it possibly do?

Screen Exposure

According to the study, childhood screen time could do harm. The amount of damage could be dependent on the amount of screen use and the age of the child. The study monitored the screen time of 47 children ages 3-5. The goal was to capture a comprehensive and well-rounded view of screen time exposure and what implications that screen time could have on childhood brain development and learning.

Any time in front of a screen, regardless of its quality or content, was included in the study. The study incorporated educational television shows, learning applications, and electronic games meant for childhood development enhancement into its definition of “screen time.” Thus, traditional screen learning methods previously thought to be benign were part of the study.

Older studies performed regarding screen use found that most children are utilizing some electronic device with a screen by the age of one. Screen use could be anything from exposure to a television show being watched to the by an older sibling, or a learning tablet made especially for toddlers. Due to the results of these previous studies, the American Association of Pediatrics currently recommends a maximum of one hour a day of screen media for children ages 2-5. 

Brain Scan and Test Results

MRI scans taken of the children’s brains displayed significant changes in white matter in children who exceeded the APA’s maximum recommendation of screen time.  Although gray matter is what composes most of the brain and where most of the brain’s “thinking occurs,” white matter plays a vital part in how a brain functions.

White matter is what connects the gray matter in brain cells to each other and the nervous system. It acts like telephone lines communicating information between the brain areas.

When the development of white matter is slowed down, the brain’s ability to communicate information also slows down. Imagine a phone line where there are not enough lines for the number of people who need to have a conversation. Callers would have to wait until there’s an available line to get their information through.

The same goes for the brain. Processing speed slowed, and information is delayed when not enough usable white matter is available.

In the cases where children exceeded the APA screen time recommendations, MRI scans found white matter to be scattered, disorganized, and not as developed as would be expected for the child’s age.

What was more telling were the areas most affected. The areas most affected by screen time were areas of the brain most used during childhood: language, cognition, and literacy. Children in the study who used more than the recommended amount of screen time were also found to score lower on literacy and expressive language tests.

Language, Literacy, and Screen-time

The study suggests that screen time is not the only element causing the brain changes. The main factor is the time spent on the screen, along with human interaction.  A mitigating factor to screen time use is time spent engaged with the people around them.

There is a correlation with the screen time used by the child and 1:1 interaction with caregivers. When a child views a screen, caregivers are more likely to use another screen themselves or allow the child to watch on their own. Every moment being in front of a screen is less time spent in 1:1 interaction with a caregiver.

For children who use screen time often,  there is little quality time left for the development of adequate communication skills. It’s this lack of valuable human interaction, as a result of excess screen time, that may be adding to the brain changes.

What can parents do?

The American Academy of Pediatrics (AAP) recommends the following screen media parameters:

  • If younger than 18 months, discourage all use of screen devices except for video chatting.
  • For children, 18-24 months choose quality shows and watch along with the child. Encourage the child to talk about the content.
  • Children 2 to 5 years old should be limited to 1 hour of quality shows per day. Caregivers should watch the screen along with the child. Create a discussion surrounding the show and how it may apply to the real world.
  • Children ages six and older should have limits placed on media use so as not to interfere with sleep and healthy activities.

The AAP recommends assigning regular media-free times for families, such as meal times and outdoor play events. Particular rooms in a house could also be designated as media-free zones, especially if small children are in those areas.

What is most important is to provide young children with a face-to-face interactive environment. Screen time is much more valuable if spent watching the same program with a caregiver, and exchanging verbal feedback in the process.

Young children require direct engagement from their surroundings to stimulate word association and problem-solving. Though screens can have benefits, they don’t replace human interaction.

There are non-verbal cues, language gradations, and social norms, which young children can’t learn from a screen. Also, the information relayed to a young child by a trusted caregiver can have more impact than information conveyed through a television character.

Interestingly, video calling on a screen with a caregiver is not prohibited or counted as screen time by the AAP. The real-time interaction from a caregiver and facial recognition can outweigh any negative impact screen time may have in these situations.

Parenting choices are individual. Every family dynamic is different. However, knowing how screen time and human interaction affects childhood brain development can help families make choices suited to their needs.

Maria Morioka, BSN, RN

Maria Morioka, BSN, RN has been a Licensed Registered Nurse in the mental health field for nearly 15 years. Maria strongly believes in educating others about the importance of mental health.

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