Jared Cooney Horvath is on a mission. In the wake of global campaigns for smartphone bans in schools and social media restrictions for under-16s, the neuroscientist wants to raise the alarm about educational technology in classrooms.

A former teacher, Horvath believes the use of screens and digital tools in schools is undermining how children learn and develop. “This might be one of the hardest truths our generation has to face,” he writes in his book, The Digital Delusion.

“Our children are less cognitively capable than we were at their age,” he says. “For nearly two centuries, the west experienced steady generational progress. Each new cohort of children grew up, on average, healthier, happier, and better educated than the last. Until now.”

Starting around the year 2000, something changed. “Across the west, IQ scores began to fall – even as time spent in school kept rising,” writes Horvath. Scores in international tests started to drop. Why? “The answer lies in the meteoric rise of educational technology.”

According to a recent Department for Education report, the UK educational technology – or edtech – market generated an annual turnover of about £6.5bn. In the US, Horvath says it is a $400bn (£295bn) mega-industry, woven into every aspect of schooling.

“We’ve been making some incredible strides on the screen-based childhood stuff which even two years ago, I did not think was going to happen as fast as it did,” he said. “But it’s not just about getting rid of screens for entertainment. It’s about reducing them as much as possible for academic learning as well if we want our kids to have deep transferrable knowledge in our heads.”

The uptake of laptops in schools – especially in the US where he lives – began in earnest in 2010-12, Horvath said. “It’s when Covid hit, that’s when every school had to pivot digital as a Band-Aid … rightly so. Better to have something than nothing.

“But when Covid finished you would assume they’d rip that Band-Aid off, but the vast majority of schools didn’t. They just stayed digital.” In the US 88% of school districts now had one-to-one computers, he said. In the UK, Covid had a similar impact.

Horvath has been studying how people learn for over 15 years and has concluded that “tech is not a very good tool for it”. He cites recent scores from the programme for international student assessment (Pisa) which takes place every three years and tracks the academic performance of 15-year-olds across dozens of countries.

In 2012, 2015 and 2018, Pisa asked students how much time they spent using digital devices during a typical school day. “The more time students spent on screens at school, the further their scores fell,” Horvath said. “On average, those who used computers for more than six hours per day scored 66 points lower than their peers who didn’t use them at all.”

Others working in the field are concerned about the risks of confusing correlation with causation. Rose Luckin is an emerita professor of learner-centred design at the UCL Knowledge Lab in London and a recognised expert on AI in education.

“[Horvath] does get certain things right,” Luckin said. “It’s true that a great deal of educational technology was sold on promises rather than proof. We did not have a huge amount of evidence. But that does not mean that all educational technology is problematic.

“In terms of that Pisa data, if you look at it on computer use and outcomes, actually moderate school device use is associated with better results than no school device use. It’s just that the heaviest daily use is the worst.”

Daisy Christodoulou, the director of education at No More Marking, an educational technology startup, agrees that society has been a “bit blase” about the impact of a lot of these new technologies.

“We are seeing across the board now a bit of a corrective, where people are realising that. But I would probably be a little bit more optimistic [than Horvath] about the potential for technology and AI in upper secondary,” she said. “Screens have not had as big an impact in classrooms in England as in the US. But I feel like there’s enough here that we should be thinking about it. I think it’s a bit blase to go, ‘nothing to see here’, move on please’.”

Dylan Wiliam, an emeritus professor of educational assessment at the UCL Institute of Education, said: “Technology may well be harming student achievement but the correlational studies that we currently have cannot support such causal claims.

“And there are many well-designed studies that show that technology can have a positive impact on student achievement. So the question, ‘Does edtech have a negative impact on learning?’ does not have a simple yes/no answer: sometimes it does, and sometimes it doesn’t.

“The question we need to be asking is, ‘when does edtech help learning?’ And the answer is, ‘it’s complicated’.”