Rethinking Screen Time: What The Science Really Says About Children And Devices

A child's furious reaction to having an iPad taken away can feel like proof that too much screen time is harmful. Yet researchers studying children's digital lives say the reality is considerably more complicated.

Concerns about tablets, smartphones, social media and video games have become increasingly common among parents. Screens are frequently blamed for poor sleep, behavioural difficulties and declining mental health. Some researchers and campaigners argue that limiting access, particularly to smartphones and social media, is an important safeguard for children.

Others caution that the scientific evidence does not support such broad conclusions.

Pete Etchells, a psychology professor at Bath Spa University, is among the academics who argue that the evidence linking screen use itself to widespread harm is weaker and more complicated than public debate often suggests. In his book Unlocked: The Real Science of Screen Time, he examines hundreds of studies on screen use and mental health and argues that many headline-making conclusions rely on limited or potentially misleading interpretations of the data.

His position is not that online risks do not exist. Rather, he argues that "screen time" is too broad a category to explain children's experiences or determine whether their technology use is harmful.

Why Screen Time Is Difficult To Measure

One of the central problems is how screen use is measured.

Much of the research relies on young people estimating how much time they spend using devices and reporting how they feel. Etchells argues that this creates considerable scope for error and makes it difficult to establish cause and effect.

A relationship between two factors does not necessarily mean that one caused the other. He has used the familiar example of ice-cream sales and skin-cancer symptoms both increasing during warmer weather: the two may rise together without one causing the other.

He also describes research examining the relationship between phone use and depression and anxiety among young people. Although screen use and mental-health difficulties were correlated, the researchers identified loneliness and time spent alone as an important additional factor.

That distinction matters because a phone can be used in very different ways. A child watching educational material, playing a game with friends, talking to relatives or endlessly scrolling through distressing content is not necessarily having the same experience.

Etchells therefore argues that simply counting hours can conceal the more important questions: What is the child doing? Who are they interacting with? Is the activity useful or enjoyable? And what is it replacing?

Research examining 11,500 brain scans of children aged nine to 12 also complicates the idea that screen use inevitably damages the developing brain. The study, involving data collected between 2016 and 2018, found associations between patterns of screen use and changes in connections between brain regions, but did not find evidence linking screen use with poor mental wellbeing or cognitive problems, including among children who spent several hours a day using screens.

Professor Andrew Przybylski of Oxford University, who has studied video games, social media and mental health, supervised the study. His peer-reviewed research has also suggested that some forms of digital activity can be associated with positive experiences rather than simply causing harm.

Etchells argues that if screen exposure were consistently producing damaging changes in children's brains, a large dataset of this kind would be expected to reveal a clearer signal.

Professor Chris Chambers, head of brain stimulation at Cardiff University, makes a related argument in Etchells' book. He questions whether claims of widespread cognitive deterioration are compatible with the broader understanding that human brains continually adapt to their environments.

The Evidence Is Not Entirely Reassuring

That does not mean there is no evidence of harm.

Jean Twenge, a psychology professor at San Diego State University, argues that smartphones and social media have played an important role in rising depression rates among American teenagers. She says she did not initially approach her research intending to establish that the technologies were harmful, but came to view them as a significant common factor.

Twenge supports delaying children's access to smartphones and social media, arguing that adolescents are more mature and generally have more stable social environments by the age of 16.

Other research has produced findings that support greater caution. A Danish study published in 2024 involved 181 children from 89 families. For two weeks, some participants were restricted to three hours of screen media a week and asked to hand over their tablets and smartphones. The researchers concluded that reducing screen use had positive effects on reported psychological symptoms and prosocial behaviour, while also noting that further research was necessary.

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A separate UK study using participants' time diaries found that greater social-media use was associated with higher reported levels of depression among girls.

These findings do not settle the wider debate, but they demonstrate why the evidence cannot simply be characterised as either proving that screens are harmful or proving that they are harmless.

Sleep is another example of the uncertainty. Although previous research has suggested that blue light from screens can interfere with sleep by suppressing melatonin, a 2024 review of 11 studies found no overall evidence that exposure to screen light during the hour before bedtime made it harder to fall asleep.

There are also online dangers that Etchells and Przybylski do not dispute, including grooming and exposure to explicit or harmful material. Those risks are distinct from the broader question of whether simply spending time looking at a screen causes poor mental health.

What Should Parents Make Of The Uncertainty?

The disagreement among researchers has left parents with a difficult problem: there is widespread pressure to reduce children's screen use, but no universally accepted formula for deciding how much is too much.

The American Academy of Pediatrics and the UK's Royal College of Paediatrics and Child Health do not recommend specific universal screen-time limits for children. The World Health Organization takes a more prescriptive approach, recommending no screen time for children under one and no more than one hour a day for children under four, while placing those recommendations within a broader emphasis on physical activity.

The absence of a single agreed limit has also contributed to what paediatrician Jenny Radesky of the University of Michigan has described as an increasingly judgemental culture among parents. She has argued that discussions about screen use can generate parental guilt without necessarily helping families understand what the evidence actually shows.

That is an important distinction. A difficult reaction when a device is taken away is not, by itself, evidence of addiction or neurological harm. Children can become intensely absorbed in many activities, from games and television to playing with siblings, and object strongly when those activities end.

At the same time, concerns about children's digital lives cannot be dismissed simply because "screen time" is difficult to measure. The content children encounter, the people they interact with, the amount of sleep and physical activity they get, and what their online activity replaces can all matter.

The scientific debate is therefore less about whether screens are universally good or bad than about whether a single measure — the number of hours spent on them — can adequately capture their effects.

That question is becoming more pressing as technology changes. Screens are moving beyond phones and tablets into wearable devices, online communities are evolving and artificial-intelligence tools are increasingly being used by young people for activities ranging from homework to conversations about personal problems.

For parents, the uncertainty can be frustrating. But it also suggests that a more useful approach may be to look beyond the clock and pay attention to what children are actually doing online, what they are missing offline and whether their digital lives are contributing positively or negatively to their wellbeing.