TL;DR: You don’t need to worry about endless scrolling on your iPhone ~too~ much.
We're spending more time in front of screens than ever before, and we're worried about it.
That increase is hardly surprising, since we now carry little screens around with us at all times. According to a 2015 Ofcom report, people spent twice as much time online in 2014 as we did in 2004, at over 20 hours a week, a rise fuelled by the ubiquity of smartphones and tablets.
The rise is most dramatic among younger people. Internet use has nearly tripled among 16- to 24-year-olds, from around 10 hours a week in 2005 to 27 and a half hours in 2014.
Of course, that doesn't tell you whether screen time is good or bad. But lots of people are concerned. An article in The Atlantic by Jean Twenge last month asked: Have smartphones destroyed a generation? It said the rise in screen time has had a "dramatic" – and negative – effect on teenagers' mental health, on their social interaction, even on their sex lives. Twenge, whose claims are highly controversial, is one of several voices to have raised these concerns in recent years.
So we spoke to four scientists to see what the evidence says about how our screen habits might be affecting our health.
"Screen time" isn't a simple thing.
"This idea that 'screen time' is a unitary concept really grows out of studies about TV time in the 1970s and 1980s," Dr Andrew Przybylski, an experimental psychologist at the University of Oxford's Internet Institute, tells BuzzFeed News. "It was ported over into the digital age."
But, he points out, that's not how we think about anything else: "We don't talk about paper time or food time or book time." Screen time could mean doing research on Wikipedia, or it could mean watching hardcore pornography. The effects of those two things will probably be very different. That's not to say we can't have meaningful discussions about "screen time", but it won't be a simple "it is good" or "it is bad".
It's ~really hard~ to do good research into it.
There's not much evidence into the impact of screen time – either positive or negative, says Dr Suzi Gage, a psychologist at the University of Liverpool. There are several studies, but the results they give are unclear and difficult to interpret. "It's not that the studies are bad," she says. "It's that they're hard to do."
Essentially, say you looked at 10,000 people who use screens lots and lots, and 10,000 people who hardly use screens at all, and you found (say) that the people who use screens lots and lots are happier than people who don't. Does that show you that screens make you happier?
Well, no. Maybe it just happens that people who use screens a lot are happier anyway. Maybe they're richer, on average, and maybe that makes them happier. You can try to "control" for that, by comparing people against others of similar income, but there still could be something you haven't thought of. "People who use screens might be different in ways that we don't always understand," says Gage. "It's hard to know what causes a correlation."
That's a common problem in this sort of research. But it's even harder with screens, because the direction of causality can get so mixed up. If people who are socially anxious use screens more, is that because the screens are making them anxious? "Perhaps they use screens more because they find it hard interacting with people face-to-face," says Gage. If that's the case, then it could be that screens actively improve such people's social lives rather than hindering them.
There's also the problem that it may not be the screens that are the problem, but the time they're taking up. "What's difficult to know, when people are using screens more, is: What aren't they doing instead?" asks Gage. "Are they sleeping less? Are they going outside less? Are they socialising less? There could be all sorts of things they're missing out on by using screens. Untangling that from the screen time itself is hard."
There might be a link between screen time and mental health, but it's complex.
Przybylski published a study in January that found that a "moderate" amount of screen time – up to a couple of hours a day on weekdays, more on weekends – was actually correlated with better mental wellbeing in teens.
Again, this might not be all that surprising. "If you've got kids who don't use screens at all, then they're not on social media," says Dr Pete Etchells, a psychologist at Bath Spa University, told BuzzFeed News. "If all their friends are on it, that means they're automatically excluded from those social groups."
If you use screens for longer than that, it does become more negative. But the effect appears to be slight. "Even at exceptional levels, we’re talking about a very small impact," said Przybylski, talking to BuzzFeed News for an earlier piece. "It’s about a third as bad as [the effect on wellbeing of] missing breakfast or not getting eight hours' sleep."
Earlier studies are also ambiguous. Gage mentioned a review of the literature, which looked at four studies of screen time and anxiety. "Two found a positive correlation, one found no correlation, one found a negative correlation." She also said there is some evidence for a correlation between depression and screen use, but again, that evidence is just not very useful for saying whether that's a cause or an effect.
Tarik Kizilkaya / Getty Images