Joe Clement and Matt Miles teach social studies at Chantilly High School in Fairfax County. They know a teacher who spent six hours jazzing up a lesson on old political cartoons with a PowerPoint presentation. Students pulled laptops off a cart so they could follow and comment on the lesson online.

The class went well. But something unusual happened, part of a series of Clement and Miles discoveries that threaten the foundations of the high-tech classroom and are recounted in their new book "Screen Schooled: Two Veteran Teachers Expose How Technology Overuse Is Making Our Kids Dumber."

The teacher mentioned his successful lesson to another history teacher. She told him about her similar lesson, using not PowerPoint and laptops but printed copies of the cartoons affixed to large newsprint sheets. Students walked around the room and made lesson-related comments on the newsprint.

He decided to try it her way. The lesson took 15 minutes to prepare. What had been a good if quiet class earlier, with students staring at their screens, became a boisterous, involving discussion. Letting students interact energized the room, brought in more comments and added the physical movement that many teens crave.

“In short,” Clement and Miles concluded, “this lesson was superior in nearly every way compared to the more complex technology-enhanced lesson.”

Their book is so contrary to conventional wisdom I wonder what the magnates of ed-tech — the widely used shorthand for the educational technology movement — will do if the practices advocated by the authors gain momentum. I am deluged with education books, but this one was hard to put down.

Their idea began with musing over their best lessons, the ones they can't wait to teach every year, so engaging that their students are shocked and sad when the bell rings. They asked themselves how much advanced technology is involved in those lessons. Their answer, and the answer from the vast majority of teachers they surveyed, was little to none.

They have come up with three core principles of good teaching: “(1) deliver instruction in the simplest possible manner; (2) focus instruction on what students are able to do; and (3) foster face-to-face human interaction and opportunities for community building.”

They don’t want to dispose of iPads, YouTube, Prezis and Google Docs, they said, but “these tools in and of themselves do not make for better teaching. In fact, as we have seen, more use of technology — inside and outside the classroom — can make it more difficult for students to learn and teachers to teach. . . . The focus of the lesson often is method of instruction (how to turn on the iPad, or the twisting and turning of the Prezi) rather than on the content or skills being taught.”

Clement and Miles are not septuagenarian stegosauruses like me, dreaming of younger days. Clement, 48, was once a UNIX administrator. Miles, 33, was an IT major before a last-minute switch to education. They know the key fact about the new classroom technologies: There is no research showing they have significantly increased achievement.

The justification for screens in class is reasonable, at least on the surface. Clement and Miles said they are often told “that since so much of modern life is dependent on technology, schools must teach these technologies.”

“This might be an appealing idea, but it is folly,” they said. “Students need no help from schools developing their tablet, smartphone, or Twitter skills. They are doing this on their own. What they need help with is critical thinking, problem solving, and community building.”

They think teachers do better presenting instruction, face to face. Freed of a preplanned program, they can stop talking and answer spontaneous questions. They can backtrack if students seem lost. They can adapt their lessons from class to class. They can query students to make sure they get it.

Most important, they can develop social connections, so crucial with teenagers, to rescue them from the screen addictions that Clement and Miles describe in chilling detail. Next week, I will get into what they say can be done to turn back the acidic distractions of the tech revolution in our schools, and save just the stuff that works.