A growing body of research is sounding the alarm over how even moderate social media use may be quietly reshaping children’s brain development—and setting them on long-term academic and cognitive trajectories that could widen over time.
Dr. Sheri Madigan of the University of Calgary, who recently wrote an editorial alongside a major study on the topic, cautions that the risks are not limited to heavy users. “It’s problematic at really high uses, but it’s also problematic even in small doses,” she says.
Clinical psychologist Dr. Mitch Prinstein, Chief of Psychology Strategy and Integration at the American Psychological Association, explains why even a few points’ difference in test scores shouldn’t be brushed off. “Kids are a moving target,” he says. “A slight shift early on may not look dramatic today, but in two, three, or five years, we could be looking at a much wider gap between heavy users and kids who spend less time online.”
Use Rises Sharply in Mid-Teens
Dr. Jason Nagata, who has been studying trends through the U.S.-based Adolescent Brain Cognitive Development (ABCD) Study, notes that social media use spikes as children get older. “We would expect that when they hit age 15, 16, 17, their use will be much higher,” he says. That increased time online could translate into even bigger differences in learning and cognition later on.
Nagata’s team has previously uncovered several troubling trends:
Nearly two-thirds of children start using social media before age 13.
The average preteen has accounts on at least three platforms.
Smartphone dependence is already signaling addictive behavior among 10-to-14-year-olds.
“Half of the kids with smartphones say they lose track of how long they’ve been using them,” Nagata notes. “A quarter use social media to escape their problems, and 11% admit it has hurt their schoolwork.”
A Vulnerable Phase for the Developing Brain
Adolescence is the second most rapid period of brain development after infancy, says Prinstein. During these years, the brain undergoes major restructuring based on habits and environment.
In one of his recent studies, Prinstein found that teens who are heavy social media users develop heightened sensitivity to digital feedback—likes, comments, and peer reactions. “If their brain is growing to be optimized for rapid, constant reinforcement on social media,” he says, “it might not be optimized for other skills they need—just as we’re seeing in these new findings.”
Global Push for Policy Reform
Madigan argues that the evidence now supports the need for stronger, age-based regulations. International momentum is already building:
Denmark announced plans to ban social media use for children under 15.
Australia has introduced guidelines requiring platforms to stop users under 16 from opening or keeping accounts, effective December 2025.
Madigan believes other countries will follow. “I think we’ll see a trickle effect,” she says. “That’s going to be really beneficial for kids.”
As concerns rise in the United States, researchers and psychologists say the conversation can no longer focus solely on screen time—it must include brain development, academic readiness, and long-term cognitive impact.