Children who spend more than two hours a day looking at a screen have worse memory, language skills and attention span, a landmark study has found.
The research, which involved children aged between eight and 11 found that those with higher amounts of recreational screen time on smart phones and playing video games had far worse cognitive skills across a range of functions.
The research, published by the Lancet Child and Adolescent Health, tracked the daily habits of 4,500 children who were then asked to carry out detailed cognition tests.
The study found that more than two hours a day of recreational screen time was associated with worse working memory, processing speed, attention levels, language skills and executive function.
The study of US children, led by the University of Ottawa, questioned thousands of parents and children on their daily habits - including time spent sleeping, using smartphones and other devices, and levels of physical activity.
Overall cognition skills were best among the one in 20 children who got between nine to 11 hours sleep, less than two hours recreational screen time, and at least an hour’s exercise daily.
These children did around five per cent better in the tests than the average child. Significantly, the study isolated screen time as the likely key factor. Children who were glued to their screens for less than two hours a day saw performance around four per cent better than the average among their group, regardless of other habits.