Teens and young adults are more likely in their free time to check their Facebook page than read a book.

And they are dumber for it.

That is Mark Bauerlein's contention in "The Dumbest Generation: How the Digital Age Stupefies Young Americans and Jeopardizes Our Future (Or, Don't Trust Anyone Under 30)," recently released in paperback (Tarcher/Penguin, $24.95).

Bauerlein, an English professor at Emory University, says Generation Y, ages 16-29, has been shaped by exposure to computer technology since elementary school.

The cost, he says, outweighs the convenience. Kids are writing more than ever online or in text messages, but it's not the kind of narrative skill needed as adults, he says. "Those forms groove bad habits, so when it comes time to produce an academic paper ... or when they enter the workplace, their capacity breaks down."

Social networking sites can give young users "the sense of them being the center of the universe," Bauerlein says.

That gives them a distorted understanding of how the world works, he says. "If you go into a room of strangers, you don't know how to relate. You can't replicate your IM habits," he says. "It closes people off from a wider engagement with the world."

Parents must do more to pull their teens away from technology, including being role models in developing intellectual pursuits: "Talk with your kids. Kids can't do this by themselves."

But Gary Small, director of the Center of Aging at the University of California-Los Angeles and co-author of "iBrain: Surviving the Technological Alteration of the Modern Mind," says teens are just as smart as ever.

They're just smart in different ways, Small says. "In some ways (technology) is hindering, in some ways it's advancing" education, he says. "It teaches our brain a different way of processing things."