2 hrs daily screen time limit makes kids more intelligent

Lancet study says a limit of two hours screen – mobile phone, television etc – time every day improves thinking ability in kids

Limiting recreational screen time to less than two hours a day improves cognitive development in kids. Provided they have sufficient sleep and physical activity.

These are the findings of an observational study of more than 4,500 US children aged 8-11 years old published in The Lancet Child & Adolescent Health journal.

Taken individually, limited screen time and improved sleep were associated with the strongest links to improved cognition. Physical activity on the other hand may be more important for physical health.

Meeting only the screen time recommendation or both the screen time and sleep recommendations had the strongest associations with cognitive development

However, only one in 20 US children aged between 8-11 years meet the three recommendations advised by the Canadian 24-hour Movement Guidelines for good cognitive development. These are 9-11 hours of sleep, less than two hours of recreational screen time, and at least an hour of physical activity every day.

The authors say that their findings indicate that adhering to the guidelines during childhood and adolescence, particularly for screen time, is important for cognitive development.

“Behaviours and day-to-day activities contribute to brain and cognitive development in children, and physical activity, sedentary behaviour, and sleep might independently and collectively affect cognition,” says Dr Jeremy Walsh, CHEO Research Institute, Ottawa, Canada.

He added: “Evidence suggests that good sleep and physical activity are associated with improved academic performance, while physical activity is also linked to better reaction time, attention, memory, and inhibition. The link between sedentary behaviours, like recreational screen time, is unclear as this research is in the early stages and it appears to vary depending on the types of screen-based activity.”

Almost one in three children (29% – 1,330/4,520) met none of the guidelines, 41% (1,845/4,520) met only one, 25% (1,129/4,520) met two, and 5% (216/4,520) met all three recommendations.

Half of the children met the sleep recommendation (51%, 2,303/4,520), 37% (1,655/4,520 children) met the screen time recommendation, and 18% (793/4,520 children) met the physical activity recommendation.

The more individual recommendations the child met, the better their cognition. In addition, meeting only the screen time recommendation or both the screen time and sleep recommendations had the strongest associations with cognitive development.