It is an issue many parents will have grappled with. Is the peace you get by handing your child a touchscreen or sitting them in front of the TV worth the undefined damage you worry it's causing? The subject resurfaced last week with one study claiming that screen time was linked with increased BMI and another finding it adversely affected children's emotional well-being.
The headlines may have struck a chord, but each study faced different criticisms. So just what can we say about screen time?
First of all, lumping all screens into one category is not helpful. "Screen time is a really enticing measure because it's simple – it's usually described as the number of hours a day using screen-based technology. But it's completely meaningless," says Pete Etchells at Bath Spa University, UK, who studies the effects of video games on behaviour. "It doesn't say anything about what you're using that time for."
When you separate the different types of screen out, the effects start to vary. Passively watching TV is not the same as learning to read on a touchscreen, which is not the same as killing monsters on a console. For instance, a recent longitudinal study of 11,000 British children found that those who watched TV for 3 hours or more a day at age 5 had a small increase in behavioural problems two years later compared with those who watched for under an hour. But they found no effects at all for those who played computer games.
Watch and learn
It's not just the type of screen that matters, but what is on that screen. "The best research suggests that the content children view is the best predictor of cognitive effects," says Heather Kirkorian who studies cognitive development at the University of Wisconsin-Madison. "Children will learn from what they watch, whether that means learning letters and numbers, slapstick humour or aggressive behaviour," she says, adding that children who watch age-appropriate, educational TV programmes often do better on tests of school readiness.
When it comes to physical effects, a number of studies have found similar results to the latest research, which shows that increased screen time is associated with a rise in BMI. But it can be hard to tease apart whether screen time actually causes the effects or whether they are linked in some other way. "It is impossible to determine with certainty that TV is causing obesity, and it is likely that other factors are involved in the complex problem of childhood obesity," says Kirkorian.
The rise of portable devices has compounded the issue. According to one study, 40 per cent of children aged 8 and younger in the US had tablets in their homes in 2013 compared to 8 per cent in 2011. Rosie Flewitt who studies Early Years and Primary Education at the Institute of Education in London says touchscreens are particularly motivating for children, allowing them to use a tool they can see is important to adults. "There is an unquestionable body of research showing that new technologies can engage children," she says. Her own studies have shown that children who struggle to learn using books often made more progress with iPads.
Flewitt's research in schools also found that iPads made children more cooperative and helped quieter kids to speak up. She thinks that is partly because children receive immediate feedback, and because the devices are multimedia. "You don't need to be able to read words to access knowledge – you can follow icons, hear words spoken," she says.
A survey of more than 1000 parents with children aged 3 to 5 and their teachers, out this month, backs up the idea that tablets can promote learning. The study found that all the children enjoy reading more when they look at stories using books and a touchscreen compared to just books.
Importantly, the performance of children from low socio-economic backgrounds who use both at home is less likely to be below average at school than if they only look at books.
What is becoming clear is that it's not the technologies themselves we should be worried out but how they are used and how people interact with them. The advantages seen in the school environment can be translated into the home – if you choose your children's digital distraction wisely.
A lot of it is common sense. Don't unthinkingly hand over your device. There are educational apps whose benefits are backed up by research, says Flewitt. Consider the type of screen time, says Etchells. Five hours sitting in front of the TV is not the same as 5 hours of some TV, a couple of hours playing on Dance Dance Revolution or some other kind of active game, followed by a Skype session with a grandparent.
And take heart: this generation's iPad is another's Jane Austen. "It's a new era," says Flewitt.
"There is a lot of scepticism just like there was when novels took off in the 18th century", she says.