Step into any college lecture hall and you are likely to find a sea of students typing away at open, glowing laptops as the professor speaks. But you won’t see that when I’m teaching.

Though I make a few exceptions, I generally ban electronics, including laptops, in my classes and research seminars.

That may seem extreme. After all, with laptops, students can, in some ways, absorb more from lectures than they can with just paper and pen. They can download course readings, look up unfamiliar concepts on the fly and create an accurate, well-organized record of the lecture material. All of that is good.

But a growing body of evidence shows that over all, college students learn less when they use computers or tablets during lectures. They also tend to earn worse grades. The research is unequivocal: Laptops distract from learning, both for users and for those around them. It’s not much of a leap to expect that electronics also undermine learning in high school classrooms or that they hurt productivity in meetings in all kinds of workplaces.