Seventeen month old toddler looking at a laptop

A study in Canada found that two year olds spend an average of 2.4 hours a day looking at screens, with this increasing to 3.6 hours a day for three year olds. Credit: BSIP/UIG/Getty

Epidemiology

Children glued to screens show delays in key skills

Greater screen time at age two corresponds to poorer scores on developmental test at age three.

Children who spend much of their time staring at screens tend to score badly on tests of cognitive and emotional development. But does screen time itself hinder growth? Or are children with developmental difficulties allowed to spend more time bathing in a screen’s glow?

To answer this question, Sheri Madigan at the University of Calgary in Canada and her colleagues analysed the development and screen habits of nearly 2,500 children in Canada. The team found that, compared with those exposed to relatively low levels of screen time, children who spent more time in front of a screen at age two scored worse on a developmental test at age three, and children who racked up more screen time at age three scored worse on the test at age five.

By contrast, poorer performance on the test did not predict that a child would spend more time looking at tablets and similar devices. This suggests that extensive screen time precedes low scores on developmental tests.