Scientists Reveal Exactly How Screen Time Affects Children's Brains

Time on screens really does affect your child's brain development and function, a new meta-analysis suggests.

On average, children aged 6 to 14 are spending 2.77 hours everyday on screens, according to studies published in the journal Global Health Research and Policy in 2023. However, the number of children spending more than three hours a day on screens rose from 1 in 10 to 1 in 5 after January 2020, with average screen time more than doubling in some countries.

"The COVID-19 pandemic, between 2020 and 2022, and the subsequent lockdowns, caused a prominent rise in reliance on digital devices by children across the globe," study author Hui Li, chair professor of the Faculty of Education and Human Development at The Education University of Hong Kong, told Newsweek.

"From playful activities to formal learning, the home environment became suffused with digital interactions. This increased digital dependence, necessitated by the pandemic circumstances, has not only persisted but is also likely to carry forward as the foundational structure of education undergoes crucial modifications in the wake of the pandemic."

These new technologies allowed us to stay connected in a locked-down world, but their sustained use may be doing more harm than good, especially among children.

"As children interact with technology, their brains are susceptible to neuroplastic changes, which may influence their cognitive, social, and emotional development," Li said. "Numerous studies have reported the negative effects of digital experiences on children's brain function and structure, using different forms of neuroimaging evidence."

To study these effects, Li and researchers from the Education University, Shanghai Normal University in China and Macquarie University in Australia analyzed 33 neuroimaging studies, published between 2000 and 2023, which assessed the impact of technology use on children's brains. In total, 30,000 children were included, across the different studies. Their results were published in the journal Early Education and Development on November 17.

Of these studies, nine looked at the physical impact of digital experiences on the structure of young children's brains. "Two studies did not find any effect, five reported negative changes, and two found a mixture of consequences," Li said. "No study noted purely positive adaptations."

These negative changes included reduced connectivity between areas of the brain involved in language and cognitive control and underdevelopment in the inhibitory control system. This is the part of the brain that allows us to control our attention, behavior, thoughts and emotions.

Other studies revealed an association between screen time and poor attention and cognitive skills. "Certain studies revealed that screen interactions led to increased processing of task-irrelevant auditory stimuli, less robust inhibitory control commensurate with increased screen time, and cognitive impairments resultant from increased infant screen use," Li said. "Furthermore, heavy users of tablet devices were seen to perform worse on cognitive tasks and exhibited abnormal brain functioning compared to non-users."

Even the studies that found positive outcomes reported mixed results. "Although elevated gray matter volume in certain brain areas corresponding to TV viewing was revealed as a positive outcome, it was counteracted by reduced verbal intelligence," Li said. "It's essential to note that none of these studies reported any completely positive impact of digital experiences on brain structures."

Not all screen time is equal when it comes to positive outcomes, and several studies found that playing video games tended to have more benefits than other forms of screentime. "One study showed video gamers outstripping non-gamers in two fMRI [functional magnetic resonance imaging] tasks, implying cognitive benefits stemming from video gaming," Li said.

With these results in mind, how long should children be spending looking at screens? "Based on the guidelines on physical activity, sedentary behaviour and sleep for children under 5 years of age issued by the World Health Organization in 2020, we tend to suggest that the screen time for 0 to 1 years should be zero minutes; for 1 to 2 years, less than half hour; for aged 2 to 5, spend no more than an hour daily on screens, and to be selective when it comes to screen-related activities," Li said.

However, simply putting harsh limits on screentime might not always be productive, or practical. "It should be recognized by both educators and caregivers that children's cognitive development may be influenced by their digital experiences," Li said. "Limiting their screen time is an effective but confronting way, and more innovative, friendly, and practical strategies could be developed and implemented. Those in policymaking positions should supply suitable guidance, involvement and backing for children's digital use."