An eight-year Finnish study found that children who spent more time on screens tended to show better cognitive processing as teenagers — a result that challenges the assumption that screen time is simply bad for developing brains.
What the Researchers Did
Researchers at the University of Jyväskylä (Jyväskylän yliopisto) followed children from childhood through adolescence over eight years. They measured physical activity, sedentary behavior, and screen time, then compared those patterns with cognitive processing in the teenage years. They also examined differences between girls and boys, and whether the intensity of physical activity mattered.
The study was led by Doctoral Researcher Petri Jalanko and published in 2026. Rather than relying on a single snapshot, the team tracked participants repeatedly — allowing them to see how early-life habits related to later cognition during a period when the brain is still developing.
Key Findings
- Screen time was linked to better cognition. Greater screen time beginning in childhood was associated with better cognitive processing in adolescence.
- Activity type mattered — and so did sex. Among girls, more light-intensity physical activity since childhood was linked to better working memory. Among boys, greater participation in guided physical activity was linked to better working memory.
- An unexpected twist. Lower levels of self-reported unsupervised exercise were associated with better cognitive processing — a pattern the researchers flag as surprising.
- Device-measured activity showed no link. Physical activity and sedentary time measured with heart-rate and movement sensors were not associated with cognitive processing. The researchers note these sensors can't tell what a person is actually doing.
"The findings suggest that screen time can support children's and adolescents' cognitive processing," Jalanko said. "Presumably, the essential point here is what kind of things they do in their screen time."
"We should not regard screen time solely as harmful but seek balance between physical activity and screen time that promotes active thinking." — Petri Jalanko, University of Jyväskylä
The researchers emphasize these are associations, not proof that screens or specific activities cause cognitive changes. More intervention studies are needed to establish cause and effect — and to understand the sex differences they observed.
Why It Matters for Your Brain
This study reframes a familiar debate. Instead of asking only "how much screen time?" it suggests asking "what kind of screen time?" Digital activities that involve learning, problem-solving, creativity, or active mental engagement may support cognitive development — while passive scrolling may not.
It also highlights that body and brain are linked, but not in a one-size-fits-all way. Girls seemed to benefit from light activity, boys from guided activity, and the method used to measure exercise changed the results entirely. That's a reminder that cognitive health is nuanced.
What You Can Do
- Choose screen activities that make you think — puzzles, coding, creative tools, strategy games, or learning something new.
- Pair screen time with regular movement, especially light activity like walking or stretching.
- Consider guided exercise if you're looking for a working-memory boost.
- Don't fear screens wholesale — be intentional about how you use them.
Source: ScienceDaily Mind & Brain
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