A study found that children who spent more time watching screens such as TVs, PCs and game consoles from an early age showed better cognitive processing ability in adolescence. Researchers stressed, however, that a causal relationship confirming screen time directly increases cognitive ability has not been established.

On Sept. 23, local time, GigaZine reported that researchers at the University of Jyvaskyla and the University of Eastern Finland analysed data from the PANIC study, which tracked children's physical activity and nutrition over the long term. The analysis covered 260 people who also took part in a follow-up survey eight years later, with an average age of 15.8 at the time. Physical activity was measured using sensors and questionnaires, screen time through questionnaires, and cognitive function using the CogState test assessing learning, attention and working memory.

The analysis showed a tendency for higher overall cognitive processing scores in adolescence as cumulative screen time increased from childhood. Some reaction-time indicators in working-memory tests were also linked. The study did not distinguish what participants did on screens, such as watching TV, gaming or searching for information. Other factors such as home environment or education level may also have affected the results, so it cannot be interpreted as meaning that spending longer looking at screens makes people smarter.

The relationship between physical activity and cognitive ability was also not straightforward. Among girls, more light physical activity from childhood was linked to better working memory, and among boys, more guided physical activity was associated with a tendency for higher working memory. By contrast, some cognitive indicators were better when unguided physical activity done independently was lower. Total activity levels or sedentary time measured by sensors showed no clear association with cognitive ability.

Researcher Petri Jaelanko (페트리 얄랑코) said screen time should not be uniformly viewed as harmful, and that the content of activities and balance with physical activity should be considered. He said screen use that encourages active thinking, such as problem solving, creativity and learning, is important.

The researchers added that additional intervention studies are needed to confirm causality and gender differences.