Lukas Müller, the Würenlos school director, attributes the success of the ban to several factors. For one, the school board agreed way back in 2007 to keep phones out of classrooms. “But it led to students using them incessantly in the breaks or taking bathroom breaks to look at their phones,” remembers Müller, who has been at the school since 2004. “That was just at the start of the iPhone boom.” Studies show that requests to turn off their phones while students are allowed to keep the devices with them during class are rarely successful, and up to 97 percent of students can’t resist the temptation to check their emails or apps. So the board decided the following year to ban phone use in the entire school area. “The students are indeed less distracted,” Müller has observed. And because his K-12 school starts at kindergarten and teaches students all the way through senior year, students get used to being phoneless in school long before they become attached to Instagram or TikTok.

But the solution isn’t as simple as banning all digital devices. The problem isn’t the use of these devices per se, but excessive use and the kind of content students access. Students who spend one to five hours per day on digital devices for learning at school score significantly higher in their mathematics lessons than those who spend no time on such devices, the OECD concludes: “In contrast, students spending over one hour on digital devices for leisure at school score more than nine points lower in mathematics and report a lower sense of belonging at school than students who spend no time on leisure digital activities.”