Researchers say children who used screens more did worse in tests, but findings are disputed

A study has linked high levels of screen time with delayed development in children, reigniting the row over the extent to which parents should limit how long their offspring spend with electronic devices.

Researchers in Canada say children who spent more time with screens at two years of age did worse on tests of development at age three than children who had spent little time with devices. A similar result was found when children’s screen time at three years old was compared with their development at five years.

“What is new in this study is that we are studying really young children, so aged 2-5, when brain development is really rapidly progressing and also child development is unfolding so rapidly,” Dr Sheri Madigan, first author of the study from the University of Calgary, told the Guardian. “We are getting at these lasting effects,” she added of the study.

The authors say parents should be cautious about how long children are allowed to spend with devices.

“Excessive screen time can impinge on children’s ability to develop optimally,” they write. “It is recommended that paediatricians and healthcare practitioners guide parents on appropriate amounts of screen exposure and discuss potential consequences of excessive screen use.”

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But the results have been contested by others in the field who say the study did not take into account what the children were using the screens for, and that the influence of screens had a smaller effect than other factors such as family income, the child’s sleep and whether they were read to.

Writing in the journal Jama Pediatrics, researchers from the University of Waterloo, the University of Calgary and Alberta Children’s Hospital Research Institute describe how they investigated the issue by looking at the screen time and development of more than 2,400 children between the ages of two and five. Data was collected at least once for each child.

At two years, three years, and five years, mothers were asked to record how much time their child spent using screens, including time in front of the TV, computer or other devices. They also completed standard questionnaires to assess their child’s development, with questions including whether the child could complete tasks such as drawing particular shapes, copying certain behaviours or forming sentences – tasks covering areas from fine motor control to communication skills.



Other aspects of the child’s life, such as their sleep and whether they had books read to them, were also considered.

On average children spent about 17 hours a week in front of screens at two years old, increasing to almost 25 hours a week at three years, before falling to 11 hours a week at five years of age.

The team say a clear trend emerged: the more time children were reported to be spending in front of screens, the worse they did on development tests. Those who spent longer with screens at 24 months showed worse performance on tests at 36 months, and a similar trend was seen for screen time at 36 months and test performance at five years.

“When young children are observing screens, they may be missing important opportunities to practice and master interpersonal, motor, and communication skills,” the authors wrote.

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Others said a study that followed children over time, rather than just offering a snapshot of development and screen time, was welcome but they noted that the study had limitations, including that it did not consider developments in technology since 2016, or look at which types of screen were being used.

The study also relied on questionnaires completed only by mothers and did not consider what the child was using the screen for, or whether they were using it alone. Furthermore, it did not show which areas of development in particular were most affected by screen time or give an idea of how much was too much when it came to using devices.

The issue of whether screen time is bad for children has become a battlefield. While some argue screen time is harmful for children’s mental and physical health, others warn of moral panic, and say evidence on the issue is of poor quality and that there is no clear sign of harm.

Prof Andrew Przybylski, director of research at the Oxford Internet Institute, said the study found less than 1% of children’s variation in developmental scores was down to screen time. “This means that upwards of 99% of the children’s developmental trajectories studied here have nothing to do with screens,” he said.

And there are other issues. “If parents think that their child is not making expected progress over time, they are likely to think their child spends a lot of time with screens,” said Prof Natalia Kucirkova of University College London.

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Dr Max Davie, of the Royal College of Paediatrics and Child Health agreed other factors had a larger impact on how children fared.

“In fact the data shows that the association with screen time is weaker than that between developmental outcomes and good sleep, reading to the child, and maternal positivity,” he said.

Nonetheless, he said, parents should balance screen time with other activities. “We would, in the light of this paper, reiterate our advice that families spend time interacting as a family, that screens are not allowed to interfere with sleep, and that screen-based interaction is no substitute for in-person contact,” he said.