Screens are often blamed for many problems in childhood, from poor sleep to less exercise. But new research from Finland suggests the picture may be more complicated.
Children who spent more time using screens over several years tended to perform better on some tests of thinking and information processing when they reached adolescence.
The study does not mean that unlimited screen use is good for children. Instead, the researchers say the type of screen activity may matter. Time spent learning, solving problems, creating things or using digital tools actively may affect the brain differently from simply watching content for long periods.
The research was part of the Physical Activity and Nutrition in Children, or PANIC, study in Finland. Scientists followed children for about eight years and examined how their physical activity, sitting time and screen use were related to thinking skills in the teenage years. The current analysis included 124 girls and 136 boys who were about 15.8 years old on average.
Researchers measured activity in more than one way. Children and families answered questions about exercise, screen use and other daily habits. Participants also wore a device that recorded heart rate and movement, giving the scientists an objective measure of how active or inactive they were.
The teenagers later completed tests from the CogState test system. These tests are designed to measure abilities such as attention, learning, speed of processing and working memory. Working memory is the mental system people use to hold information for a short time while doing something with it, such as remembering part of a math problem while solving the next step.
One of the most surprising findings involved screen time. Young people who had accumulated more screen use from childhood onward tended to show better cognitive processing in adolescence. This went against the simple idea that more time on devices must always be harmful to thinking ability.
Doctoral researcher Petri Jalanko from the University of Jyväskylä said the result may depend on what children are actually doing on screens. Digital activities can include reading, searching for information, playing strategy games, writing, coding, creating music or art, and communicating with others. Many of these activities require attention, planning, memory and problem-solving.
That does not mean every kind of screen use is equally useful. Passive scrolling or long periods of entertainment may have very different effects from activities that require active thinking. The study did not provide enough detail to say exactly which kinds of screen use were most strongly connected with better cognitive performance.
The researchers also found that the connection between physical activity and thinking skills differed between girls and boys. Among girls, more light physical activity from childhood onward was associated with better working memory during adolescence. Light activity can include easy walking, casual movement and other activities that are not intense enough to cause heavy breathing.
Among boys, a different pattern appeared. More participation in organized or guided physical activity over the years was linked with better working memory. This could include sports practices, coached exercise or other planned activities, although the study cannot prove that organized exercise itself caused the better memory scores.
Another unexpected result involved exercise done without supervision. Lower levels of self-reported unsupervised physical activity were associated with better cognitive processing in adolescence. This finding is difficult to explain and shows why the relationship between movement and brain function may not be simple.
Interestingly, the data from the movement and heart-rate device did not show a clear link between overall physical activity or sedentary time and cognitive performance.
The researchers noted that a sensor can tell when someone is moving, but it cannot tell what they are doing. Sitting while reading a difficult book and sitting while passively watching videos may look identical to the device even though the brain is being used very differently.
The same problem applies to physical activity. A device may detect movement but cannot fully capture whether the activity involves teamwork, learning new skills, making quick decisions or social interaction.
These features may help explain why questionnaires about specific activities sometimes showed associations that the device measurements did not.
The study is important because childhood and adolescence are major periods of brain development.
Skills such as attention, memory and information processing can influence school performance and may affect later education and work. Understanding which daily activities support these abilities could help families and schools make better choices.
However, the findings should not be read as proof that increasing screen time will improve a child’s brain.
This was an observational study, so it can only show that two things were connected. Children with stronger thinking skills may be more likely to choose certain screen activities, or family background, education and other factors may influence both screen use and cognitive performance.
The relatively small study group also means the findings need to be repeated in larger and more diverse populations. In addition, screen technology changes quickly, so the way children used devices during the study may differ from the way teenagers use phones, games and social media today.
More detailed research is needed to separate educational, creative and social screen use from passive entertainment.
Overall, the study supports a more balanced view. Physical activity remains important for heart health, fitness, sleep and many other parts of well-being, while some forms of screen use may also challenge the brain in useful ways.
The key message is not that screens are good or bad, but that what children do during screen time may matter as much as the number of minutes they spend in front of a device.
The research was published in the journal Pediatric Exercise Science. The authors say future intervention studies are needed to test cause and effect and to understand why girls and boys may respond differently to various types of activity and screen use.
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