The research behind Stillna

Researchers disagree about a lot. Not about sleep.

Over 120 researchers from both sides of the screen debate worked through 26 claims together. Sleep got the strongest backing: heavy phone use disturbs it, and on that the panel came about as close to unanimous as this field gets.

On the rest they were more careful. Attention problems and addiction-like patterns do show up in the data, but the research cannot yet say screens are the cause. And age limits and phone-free schools have too little evidence behind them to call a solution.

The report is not peer reviewed yet. We are following it.

Phone-free schools helped, mostly the girls

Norwegian middle schools, administrative and survey data. On average not much changed for grades or mental health. But the average hides a clear difference between boys and girls.

Girls made less use of mental health care, got better grades and more often reached an academic track, most strongly among those from tougher home backgrounds. Bullying fell for both. The author calls it a low-cost policy that works, particularly for girls.

A phone in the bedroom disturbs sleep, even switched off

Meta-analysis of 20 studies with 125,198 children. Using the phone at bedtime roughly doubled the odds of too little sleep. Its mere presence in the room, unused, was enough for a clearly raised risk. The result holds in an updated 2024 meta-analysis (opens in a new tab).

The notification alone is enough to lose the thread

Merely receiving a notification, without touching the phone, impaired concentration on a demanding task as much as actually using the phone.

About 1 in 4 young people show problematic smartphone use

41 studies with 41,871 children and young people: a median of 23 per cent meet criteria for problematic smartphone use, linked to worse sleep and wellbeing. Newer data from 2024 (opens in a new tab) suggest the share has grown since.

A phone-free school day is not enough on its own

1,227 British pupils: schools with strict phone rules had less use during the school day, but the pupils' total screen time and wellbeing did not differ. In practice the time moved to after school.

When the whole family cuts back, the children feel better

Randomised trial with 89 Danish families: two weeks of sharply reduced leisure screen time measurably improved the children's mental wellbeing. One of the few studies showing cause, not just correlation.

The phone on the table takes a slice of working memory

Having your own phone visible, switched off and untouched, impaired working memory compared with keeping it in another room. Later meta-analyses (2023 (opens in a new tab), 2024 (opens in a new tab)) confirm the effect but show it is small, clearest in those most dependent on their phone.

How and what matter more than how much

Meta-analysis of 42 studies with 18,905 young children: more screen time goes with weaker language development, but educational content and watching together go with stronger. What the screen is used for matters.

Phone-free schools lifted the weakest pupils most

130,482 British pupils: when the schools went phone-free, results rose, most for the lowest-achieving fifth. One of the clearest quasi-experiments in the field.

The earlier the first phone, the larger the risks

Among 10,588 children, twelve-year-olds with their own smartphone more often had too little sleep and depressive symptoms, and were more often overweight, than those without, and the earlier the phone arrived, the larger the risk. Support for the advice to wait.

The link holds when inherited risk is accounted for

8,324 children followed for four years: more time on social media was linked to slowly rising attention problems, even after controlling for genetic ADHD risk, and with no link in the other direction. TV and gaming showed no such pattern.

Small, two-way links, and content decides

Meta-analysis of 117 longitudinal studies with nearly 293,000 children: small associations in both directions between screens and emotional problems, strongest for gaming. Content and context mattered more than the minutes. A reminder not to overstate.

Three seconds of interruption is enough to double the errors

An interruption of about 2.8 seconds doubled the errors in a multi-step task. At 4.4 seconds they tripled. The cost lies in finding the thread again.

Always follow the GPS, and finding your own way gets harder

The more GPS someone had used over their life, the weaker their spatial memory. Among those followed for three years, it declined fastest in the heaviest GPS users. A clear case of losing what you do not use.

A little less lasts longer than a full detox

619 adults were randomly assigned to either a week without their smartphone or one hour less a day. Four months later the reduction group had kept the most: less screen time (45 minutes a day less, against 38), more exercise, better mood.

The authors’ conclusion: there is a right dose, and total abstinence is not needed.

A short pause stopped one in three app openings

280 people got a short breathing pause every time they opened an app they had picked themselves. 36 per cent of the time they put the phone down instead. After six weeks those apps were opened about half as often.

A little friction goes a long way.

Every extra hour costs about eleven minutes of sleep

Meta-analysis of 17 studies of children aged 5 to 10: for every hour on a phone or tablet, the children slept on average eleven minutes less. Those who used them were almost twice as likely to sleep too little, and more likely to sleep badly.

An association, so the cause is not proven. But the direction is clear, and you can do the arithmetic.