By Jonathan Zimmerman

Dear high school student:

Can we talk? It's about computers. No, not the Lower Merion laptops; we're all sick of that subject.

I'm talking about computers in general. And I've got some bad news for you: They make you dumber.

There, I said it. And so have numerous researchers from a wide array of fields. It's time to take them seriously.

The first problem with computers is that they distract you. Did you catch that, or were you checking Facebook?

If you were on Facebook or another site, we have strong data showing that you won't understand or remember what I wrote as well as you would if you were only reading my article. As Stanford professor Clifford Nass has shown, avid "multitaskers" perform worse on almost every measure of cognitive skill.

Nass expected to find the opposite, because multitaskers have suckered us all - and themselves. They told Nass they were better at different tasks while doing them simultaneously. "Look, I can study for calculus and iChat with my boyfriend and watch Glee, all at the same time!" Yes, and you do all of them less effectively than if you were doing them separately.

Are computers the only reason multitasking has spiked? Of course not. There's also this little gadget called a cell phone. And there's TV and radio and your annoying younger brother. But no serious person can doubt that computers have increased our propensity to do more than one thing at once. And that makes us do each thing worse.

Then there's the book problem. Remember books? Those relics of a long-lost time, with pages and bindings and covers? It turns out that the more time you spend on a computer, the less you read them for pleasure.

Here you might reply, "So what?" Well, the less you read, the worse you do on standardized reading tests. If you want to improve your SAT score, don't invest in a high-priced tutor. Just turn off your computer and open a book. It works.

And here you might reply, "I do read, but I read on a computer."

But as former Sun Microsystems engineer Jakob Nielsen has demonstrated, people read on screens differently - and, yes, worse - than in print. Using an eye-tracker, Nielsen found that screen readers jumped about and rarely absorbed a full article or even a paragraph. Why do that when there's something more interesting calling out, "Click on me!"? And if that's not to your liking, well, here's another link, and another.

Now, if you're really clever, you'll hit me with some good old-fashioned American techno-futurism. "See, Professor Zimmerman, you're from that '1.0 World,' where people actually digested full articles and books, and wrote linear texts like your boring op-ed pieces. But we're entering a Brave New '2.0 World,' my friend." In the soon-to-be-eclipsed age of books, students had to passively absorb whatever the text said. But now they interact, inquire, collaborate, innovate.

Please. Every time a new technology develops, there's an American telling us it's going to transform education. In 1922, Thomas Edison predicted that the motion-picture technology he invented would "revolutionize our educational system." In the 1930s, similar claims were made of radio. Ditto for television in the '50s and '60s, and now computers.

But education hasn't changed. And it won't. I teach college students, and the things I ask them to do - analyze, synthesize, critique - are exactly what I learned at their age. And computers don't make it any easier. To the contrary, they get in the way.

Back in the '80s, as the so-called war on drugs escalated, public-service announcements showed a guy with a frying pan and an egg. "This is your brain," he said, holding up the egg. Then he cracked it into the pan and said, "This is your brain on drugs." Camera back to the guy: "Any questions?"

This is your brain, the most remarkable, dynamic learning machine ever devised. This is your brain on computers, which make you learn less. Any questions?

Jonathan Zimmerman is a professor of education and history at New York University. He wrote a longer version of this for the Merionite, the school newspaper at Lower Merion High, where his two daughters are students. E-mail: jlzimm@aol.com.