Screen Time Reduces Our Cognitive ability
Limiting recreational screen time screen time to less than two hours a day, and having sufficient sleep and physical activity is associated with improved cognition, compared with not meeting any recommendations, according to 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, while physical activity may be more important for physical health. However, only 1 in 20 US Children aged between 8-11 years meet the three recommendations advised by the Canadian 24-hour Movement Guidelines to ensure good cognitive development-9-11 hours of sleep less than two hours of recreational screen time, and at least an hour of physical activity every day.
The study found that US children spend an average of 3.6 hours a day engaged in recreational screen time. The authors say that their findings indicate that adhering to the guidelines during childhood and adolenscence, 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 behavior, and sleep might independently and collectively affect cognition’’ says Dr Jeremy Walsh, CHEO Research Institute, Ottawa, Canada. ‘’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 stage and it appears to vary depending on the types of screen-based activity’’.
In the study, data was analysed from4,520 children from 20 sites across the USA. Children and parents completed questionnaires and measures at the outset of the trial to estimate the child’s physical activity, sleep and screen time. Children also completed a cognition test, which assessed language abilities, episodic memory and processing speed. The study controlled for household income, parental and child education, ethnicity, pubertal development, body mass index and whether the child had had a traumatic brain injury.
The more individual recommendation the child met, the better their cognition. In addition, meeting only the screen time recommendation or both screen time and sleep recommendations had the strongest associations with cognitive development. Dr Walsh concludes: ‘’ We found that more than two hours of recreational screen time in children was associated with poorer cognitive development. More research into the link between screen time and cognition is now needed, including studying the effect of different types of screen time, whether content is educational or entertainment, and whether it requires focus or involves multitasking. Based on our findings, paediatricians, parents, educators, and policymakers should promote limiting recreational screen time and prioritising healthy sleep routines throughout childhood and adolescence’’