Does screen time make kids dumber? What the studies actually show

In August 2026, a Finnish study made headlines: kids who spent more time on screens did better on memory and attention tests as teenagers. At the end of September, a large review in the medical journal JAMA Pediatrics said almost the opposite: more screen time, worse results.

So do screens make kids dumber, or smarter? Neither. And a close look at the two studies shows why.

A quick note before going further: I’m not a researcher, and every study cited here links to its source. I’m also the developer of pourquoi.app, an app about how we use our phones, so I have a stake in this. I’ll come back to it briefly at the end.

The Finnish study vs the JAMA Pediatrics review: two opposite answers

The first study comes from the University of Jyväskylä, in Finland, and was published in August 2026 in the journal Pediatric Exercise Science. The researchers followed 260 children for eight years, from ages 7 to 9 at the start to 15 to 17 at the end. The kids who spent the most time on screens (TV, computer, video games, phone) scored slightly better on memory and attention tests as teenagers. The link held even when comparing children who started out at the same level and whose parents had the same amount of education. The authors themselves describe the effect as modest.

Two details matter. The first measurements were taken between 2007 and 2009, long before TikTok and short videos. And screen time came from a questionnaire that lumped every kind of use together, so nobody knows what the kids were actually doing. Petri Jalanko, who led the study, says so himself: “Presumably, the essential point here is what kind of things they do in their screen time.”

The second study is on a different scale entirely. Published at the end of September 2026 in JAMA Pediatrics, an American medical journal devoted to children, it comes from a team led by Sheri Madigan at the University of Calgary, in Canada. The team pooled 23 meta-analyses, which are studies that combine the results of many other studies on the same question. Together they cover nearly 3 million children and teens in 64 countries. The review found that more screen time goes hand in hand with slightly weaker outcomes in several areas, including learning, language, behaviour and managing emotions.

The headlines went one way, then the other. If you’re a parent, it’s easy to feel lost.

Why the two studies don’t really contradict each other

The Finnish study and Madigan’s review have three things in common, and those three things explain the apparent contradiction.

They show correlation, not causation. Think of books. Children who grow up with lots of books at home tend to get better grades. It isn’t the books on the shelf that raise the grades. It’s families where people read, talk and have time for each other. The same goes for screens, and the arrow can even point the other way: a child who struggles at school may retreat to a screen more often. Madigan acknowledges it: “Because our findings are correlational, they don’t prove that screens cause these developmental outcomes.”

The effects are tiny. Tatiana Íñiguez Berrozpe, a sociologist at the University of Zaragoza in Spain, commented on the JAMA Pediatrics review. She says the link is real but very small: screen time accounts for only about 1% of the differences between children. In other words, when one child does better than another, it comes down almost entirely to other things. In the Finnish study, too, the effect is small.

Neither study knows what the kids were doing on their screens. Esther van Sluijs, of Loughborough University in England, points out that the JAMA Pediatrics review didn’t have enough data to separate social media, gaming and videos. Yet an hour building a world in a game, an hour on a video call with a grandparent and an hour of back-to-back videos are not the same hour.

At heart, the Finnish study and the Canadian review say the same thing in different words: screen time on its own explains very little.

Screen time and kids’ brains: what the big studies show

The worry isn’t new. In 2008, writer Nicholas Carr asked in The Atlantic, “Is Google Making Us Stupid?” He later expanded the essay into a book, The Shallows. His concern was attention: that skimming from link to link was wearing down our ability to read and think deeply.

On children specifically, a well-known critic is French neuroscientist Michel Desmurget, whose 2019 book was later published in English as Screen Damage. His strongest argument is about time: every hour on a screen is an hour taken from something else, like sleep, reading, play or talking with adults. He also argues that screens are lowering IQ, a claim other researchers dispute. Where IQ scores really are falling is Norway, among men born after 1975 (the data come from military conscription tests, which is why they only cover men). The researchers point to environmental causes, but can’t say which ones.

Since then, several large studies have tried to get a clearer picture.

In France, the Elfe study. This large French study has followed more than 18,000 children born in 2011, and an analysis of nearly 14,000 of them, from ages 2 to 5½, found that the link between screen time and development scores became small once family lifestyle was taken into account. Context mattered more: 41% of the children had the TV on during meals at age 2, and that went with weaker language skills.

In the US, the ABCD study. Researchers at the Karolinska Institute in Sweden and Vrije Universiteit Amsterdam used this large long-term study of American children to look at nearly 10,000 kids aged 9 and 10, more than 5,000 of whom were assessed again two years later. They took account of genetics and family background. Over those two years, children who played more video games than average saw their IQ rise about 2.5 points more than the average child’s. To put that in perspective, the average IQ is 100, and two in three people score between 85 and 115. So it’s a real difference, but a small one. Time spent chatting online (messages, social media, video calls) had no clear effect. The authors note that they didn’t look at sleep, physical activity or school performance. As Tatiana Íñiguez Berrozpe put it in her comment on the JAMA Pediatrics review, “it matters less how many hours devices are used for and more which device is used, for what purpose, with whom, and at what stage of development.”

In England, an expert panel on under-5s. In March 2026, a panel advising the government in England published a report on screen use by children under 5. It found fairly consistent, though low-quality, evidence that more screen time goes with less sleep at night. On attention and other thinking skills, the findings were mixed. And where the evidence was thin, the panel says it erred on the side of caution.

Study	What it shows	What it doesn’t show
Finland, 2026: 260 children followed for 8 years	More screen time in childhood, slightly better scores as teens	What the kids were doing, or the effect of today’s screens
JAMA Pediatrics, 2026: nearly 3 million children in 64 countries	More screen time, slightly weaker outcomes (learning, language, emotions)	Causation, or the effect of social media, games or videos on their own
Elfe, 2023: nearly 14,000 children aged 2 to 5½	TV during meals goes with weaker language skills	That screen time itself has a strong effect, once lifestyle is accounted for
ABCD, 2022: nearly 10,000 children aged 9 and 10, followed for 2 years	Gaming goes with a slight IQ gain; chatting online, no clear effect	The type of game, or causation

3 questions to ask about any screen time study

Next time a headline worries or reassures you, three questions will tell you what it’s worth.

1. Is it causation or correlation? Phrases like associated with, linked to or tied to mean correlation. Showing causation takes an experiment, where one group’s screen use changes and another’s doesn’t. Those experiments are rare.
2. Is the effect big or tiny? A result can be real and still make almost no difference in a child’s life. Look for words like small or modest, or a figure like the 1% above.
3. What kind of use, and instead of what? TV on in the background, a game, a video call, back-to-back videos at night: if a study lumps them all together, it can’t tell you much about your own situation.

The real question: instead of what?

Almost everyone agrees on one thing, from Michel Desmurget to Sheri Madigan. Madigan says digital technologies can be wonderful tools for children, but that they can also “crowd out what children really need to thrive”: sleep, physical activity, human connection, learning and play.

Sleep is also one of the areas where the panel in England found fairly consistent evidence. Nothing suggests that a screen at night makes anyone dumber. What it does is shorten the night, and sleep is what counts.

Screen time guidelines for parents

Rather than watching the clock, look at what the screen replaces:

• Evenings: is the screen eating into sleep?
• Meals: is the TV or a phone taking the place of conversation? The Elfe study measured it at age 2, but at any age, a meal without screens leaves room to talk.
• Play and going out: is there still time to move, to be bored, to play with other kids?
• Your own phone: kids also see how you use yours.

Age guidelines differ between the US and England. The American Academy of Pediatrics (AAP) updated its recommendations in January 2026. Its policy statement says the right amount varies from family to family, and offers ranges only for parents who want a number. England published its first official guidance for under-5s in March 2026.

• Under 2: England’s guidance says to avoid screen time except for shared activities with family that encourage bonding, interaction and conversation. The AAP says babies don’t learn from screens, but that an occasional short, high-quality video does no harm.
• Ages 2 to 5: England says an hour a day at most, less if possible. The Royal College of Paediatrics and Child Health (RCPCH), which represents children’s doctors across the UK, also backs a limit of an hour a day from 2 to 4. The AAP suggests a cap of under an hour a day for toddlers and preschoolers.
• School-age kids and teens: the AAP’s suggested cap is around one to two hours a day of entertainment media, not counting schoolwork, and it can go higher depending on the family. England’s guidance for ages 5 to 16 was announced for later this year, and the government says it will avoid blanket rules.
• First phone: the AAP says research doesn’t point to a specific age. It depends on the teen.
• Meals and bedtime: the AAP, like England’s guidance for under-5s, says to keep mealtimes and bedrooms screen-free and to avoid screens in the hour before bed.

These are precautionary guidelines, not thresholds proven by research. The panel behind England’s guidance says so itself: its time limits aren’t based directly on evidence, but on what’s known about child development. And the AAP says what matters most is high-quality content and making room for sleep, play, physical activity and reading. If evenings, meals and play still get their time, the exact number of hours matters much less. The article on school phone bans sorts through the studies on schools the same way, and also looks at parents’ phones.

And your own phone: did you mean to open it?

That leaves the last item on the list: your own phone. For us adults, the question isn’t “is it making me less intelligent?” It’s “did I mean to open it?”

Watching a documentary because you wanted to, calling a friend, looking up directions: you decided that. Opening Instagram without thinking while you wait for your coffee, then looking up twenty minutes later: not really. Your screen time counts them the same. They have nothing in common.

You don’t need to feel guilty to tell them apart. For a few days, just jot down, on paper or on your phone, whether you knew why you were opening an app. Seven days to see where your screen time goes lays out the method, day by day.

This is where I come back to pourquoi.app, the app I built (“pourquoi” is French for “why”). It’s not a parental control: it goes on your own phone, not your child’s. When you open one of the apps you’ve picked, it asks “why now?” and offers six answers: “Communicate”, “Search”, “Work”, “Entertain myself”, “No reason”, “Other”. Then the app opens, or you close it. It doesn’t block anything, and your answers stay on your phone. A teen can install it on their own phone if they choose to, and you won’t see any of their answers. The question is free; Premium prices are on the home page. No study has tested pourquoi.app itself, and it won’t tell you anything about your IQ. Setup takes a few minutes: iPhone guide, Android guide.

Frequently asked questions

Does screen time make kids dumber?

There’s no evidence that it does. Large studies find very weak links between screen time and how children do, either way, and none of them shows that screens are the cause. What kids do on screens, when they use them and what the screen replaces (sleep, movement, time with other people) matter more than the number of hours.

What did the 2026 JAMA Pediatrics screen time study find?

Published at the end of September 2026 by a team at the University of Calgary, this review pools 23 meta-analyses covering nearly 3 million children and teens in 64 countries. It found that more screen time goes hand in hand with slightly weaker outcomes in learning, language and managing emotions. The link is very weak, it’s a correlation rather than proof of cause, and the review couldn’t separate types of use.

Do video games make kids smarter?

One study followed more than 5,000 American children for two years. Those who played more video games than average saw their IQ rise about 2.5 points more than the average child’s, a real but small difference. It’s a correlation, not proof, and the study didn’t separate types of games. What it does show is that not all screen use is the same.

Is screen time lowering IQ?

No one has shown that. In Norway, IQ scores from military conscription tests, which cover the vast majority of Norwegian men, have been falling for men born after 1975, after rising for decades. The researchers point to environmental causes, but can’t say which ones.

How much screen time is recommended by age?

It depends on who you ask. In the US, the American Academy of Pediatrics says it varies from family to family; for parents who want a number, it suggests a cap of under an hour a day for toddlers and preschoolers, and around one to two hours of entertainment media for school-age kids and teens, or more depending on the family. In England, official guidance says to avoid screens before age 2, except shared activities with family, and to keep to an hour a day at most from 2 to 5.

Who writes here

I’m Nicolas Carrion, and I designed and built pourquoi.app, an app about phone habits. I’m not a researcher or a doctor, so every study and figure here links to its source, all checked in early October 2026. My background and how to reach me are on the about page.