Study links longer childhood screen time to stronger teen cognition

Finnish researchers found that longer screen time in childhood was associated with better cognitive ability during adolescence, ERR reported. The researchers stressed that the findings show associations and do not prove that screen time directly causes changes in cognitive abilities.

Researchers at the University of Jyväskylä analysed how physical activity, sedentary behaviour and screen time measured from childhood through adolescence were associated with young people’s ability to process information. They also examined differences between girls and boys.

The analysis was part of an eight-year follow-up in the PANIC study on children’s physical activity and nutrition. It included data from 124 girls and 136 boys, whose average age was 15.8 years.

Physical activity and sedentary behaviour were measured using questionnaires and a device that recorded heart rate and movement. Learning ability, attention and working memory were assessed with a specialised test.

Unexpectedly, longer screen time in childhood was associated with better cognitive ability in adolescence.

Petri Jalanko, a doctoral researcher at the University of Jyväskylä, said the findings suggest that screen time could support children’s and young people’s cognitive development. However, what people do during screen time is decisive. The associations observed in the study may therefore be linked to activities involving learning, creativity, problem-solving or other forms of mental effort that can be carried out using screens.

Jalanko said screen time should not be viewed as solely harmful. Instead, a balance should be sought between physical activity and activities that encourage active thinking.

Differences between girls and boys

The relationship between physical activity and mental ability was more complex. Among girls, light-intensity activity practised since childhood was associated with better working memory. Among boys, better working memory was associated with supervised training that continued from childhood through adolescence.

The researcher added that, from the perspective of brain health, boys and girls may benefit from rather different forms of exercise.

Physical activity and sedentary time measured with the device monitoring heart rate and movement were not associated with cognitive ability. The researchers suggested that one possible explanation is that, although sensors can measure movement and physiological activity, they cannot accurately determine what a person is doing while moving or resting.

According to Jalanko, the findings show that the links between physical activity, sedentary behaviour and mental ability are multifaceted and depend on sex, the type of movement and the assessment method.