A Finnish eight-year study challenges the notion that all screen time is detrimental, suggesting content and engagement levels play a crucial role in cognitive development among children and teenagers.
A Finnish study is challenging the assumption that all screen time is harmful, finding that children and teenagers who spent more time on screens over the years tended to show stronger cognitive processing in adolescence. The researchers said the result should not be taken as a licence for unlimited device use, but as evidence that the content and purpose of screen time matter, especially when it encourages active thinking, problem-solving and learning.
The work, drawn from an eight-year follow-up of the PANIC study on children’s physical activity and nutrition, involved 124 girls and 136 boys with an average age of 15.8. Published in Pediatric Exercise Science, it examined how physical activity, sedentary behaviour and screen use from childhood through adolescence related to cognitive performance, including learning, attention and working memory. Doctoral researcher Petri Jalanko of the University of Jyväskylä said teachers and parents should guide children towards screen use that supports creativity and education rather than treating screens as inherently damaging.
The findings also pointed to a more complicated relationship between movement and brain function than public health messaging often suggests. In girls, more light-intensity physical activity over time was linked with better working memory, while in boys, more guided physical activity from childhood into adolescence was associated with stronger working memory. By contrast, less self-reported unsupervised physical activity was associated with better cognitive processing, and activity or sedentary time measured by heart rate and movement sensors showed no clear link to cognition. That may reflect the limits of wearable devices, which can measure movement but not the nature of the activity itself.
The new results sit alongside earlier research suggesting that movement patterns and cognitive development are closely tied during adolescence. Other studies have found that moderate-to-vigorous physical activity is associated with stronger neurocognitive measures, while sedentary time may be linked to weaker ones. At the same time, a broader scoping review has argued for public health approaches that consider physical activity, screen exposure and sleep together rather than in isolation.
Jalanko said the central lesson is balance. Rather than framing screen time only as a risk, he argued, families and schools should think about how to combine it with physical activity in ways that keep children mentally engaged. The study does not prove cause and effect, and the authors said more intervention research is needed, particularly to clarify whether boys and girls benefit from different kinds of exercise and how intensity shapes cognitive change.
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