Initially published in Spanish on 14 April 2025 by Catherine L’Ecuyer and Miguel Ángel Martínez-González, in La Razón.
There is scientific evidence to suggest that digital devices in the classroom bring, at best, no tangible benefit to learning.
Picture the following headline: “Health inspector squanders €2 billion by recommending the destruction of thousands of expired and deteriorated vaccines.”
Who, in truth, squandered those €2 billion? Was it those who financed the purchase without proper scrutiny? Or those who resisted the expenditure or detected the flaw? Would we blame the inspector who recommended disposing of the defective goods—or the one who warned of the oversight before the purchase was made?
Not long ago, we encountered this striking headline in a Spanish newspaper:
“Anti-screen movement to flush away €2.145 billion invested in schools.“
Sensationalist headlines are nothing but digital bait for disoriented parents. The good news, however, is that there are fewer and fewer lost in the fog. Parents have lived with this issue within the walls of their own homes for years. Their instincts are no longer bewildered. They have seen, with their own eyes, the harmful effects of screens on their children—and on an entire generation. They trust less and less in a neatly packaged industry increasingly detached from reality, and more and more in the quiet, sobering truths witnessed daily in their own living rooms.
They are beginning to realise that the siren song of technology contradicts reason within the realm of education—and they mourn the fact that schools seem more invested in placebo effects than in scientific evidence.
So, what do the studies actually say about social media, smartphones, and tablets in the classroom ? After all, as Daniel Moynihan so astutely observed, “Everyone is entitled to his own opinion, but not to his own facts.”
Today, a robust body of evidence has established a causal relationship between social media use and the deterioration of young people’s mental health. This was unequivocally stated by the U.S. Surgeon General in his official report on social networks and mental health.
Further, there is strong scientific consensus that digital devices in classrooms—whether used for educational or personal purposes—confer, at best, no benefit to learning. At worst, they actively impair it.
Of course, there will always be outlier studies, often of lesser methodological rigour, that proclaim the opposite—usually based on “non-significant” results, which, by definition, signify nothing. And there will always be those eager to seize upon such feeble findings to prolong the slow agony of EdTech’s foretold demise.
Take, for instance, a recent study published in a minor and recently founded journal from the Lancet group (not The Lancet, with its long and respected medical lineage dating back to 1823). This February, that journal published a weak and inconclusive study claiming to find « no significant » evidence that smartphone bans in schools correlate with improved adolescent mental health.
Despite its fragility and even with the biases openly acknowledged by its own authors, this study made headlines and was eagerly cited by those all too comfortable with the widespread presence of screens.
It is important to be aware of the study’s methodological shortcomings:
- The results rely solely on subjective, self-reported data from students. No objective measurement was used. The authors dismissed data directly collected from devices as implausible. Thus, students themselves (with what degree of candour?) provided information on both their screen time and their mental health.
- The authors admit to selection bias. Though 325 schools were invited, only 30 participated—and the characteristics between comparison groups differed markedly. Other variables may have distorted the outcomes.
- The study is purely observational. The authors themselves acknowledge that their chosen method—a cross-sectional design—is the least suited to drawing causal inferences. It’s Research 101: this methodology cannot determine which came first, the chicken or the egg.
With such a flimsy design, it’s hardly surprising that no associations were found. But let us be clear: failing to find evidence of causality is not the same as finding evidence of no causality. Absence of evidence is not evidence of absence. To claim equivalence between allowing and banning devices would require what is known as an “equivalence study”.
For years, pro-screen voices have insisted that correlation does not imply causation. And they are right. But to establish or refute causation, a different methodology is needed—randomised experimental trials, not mere observational studies. As we have noted—and as the U.S. Surgeon General affirms—such interventional studies already exist. They show clear causal links between technology use and the decline in young people’s mental health.
Let us not forget: tablets in the classroom often act as gateways to recreational usage, including social media.
In truth, the term “anti-screen movement” is a misnomer. What we are witnessing is not a reactionary backlash, but rather a growing concern for the mental wellbeing of young people, backed by a body of evidence demanding a public health response.
Likewise, it is disingenuous to speak of a technological “investment” in education. An investment presupposes a return. If there is no return, or positive impact, it was not an investment—it was a squandering.
The question that should concern and engage parents is this: If numerous experimental studies already demonstrate a causal link between technology use and declining mental health, why do some experts continue to ignore them—choosing instead to cite studies of questionable rigour that favour a pro-technology stance?
That is a question best posed to them.
Catherine L’Ecuyer, bestselling author of It looks better in 3D and The Wonder Approach
Miguel A. Martínez-González, Professor of Preventive Medicine and Public Health (MD, PhD, MPH) at the University of Navarra & Associate Professor of Nutrition at Harvard University.
