Educators have worried for years over the effects of too much television on young people. But how does that impact extend beyond television, and how is it influencing people of all ages? Those are questions posed by New York University professor Todd Gitlin in a book called Media Unlimited: How the Torrent of Images and Sounds Overwhelms Our Lives.

For many Americans, electronic sounds and images have become almost a constant companion whether they're watching a television news program, doing business by cell phone, talking to a friend over the Internet, or going out for the evening to see a movie.

Dan Brooks, 18, says he starts turning dials and pressing buttons as soon as he heads out the door for school each day.

"I listen to 'Elliot in the Morning' on the radio on the way over," he says. "When I get back I check my e-mail for work or pleasure. I talk to my friends online. Whenever I have time, I check my schedule on my palm pilot or my cell phone, my cell phone has my schedule on it. I take my cell phone with me wherever I go. And when I get home I maybe watch a video or watch something on TV."

Social and cultural critic Todd Gitlin has explored specific aspects of the media in earlier books and articles. In Media Unlimited, he wanted to take a broader look at how all kinds of electronic communication affect American life.

"In households with children in the United States, in a very good survey that was done about three years ago, the average child is in the presence of media about 6.75 hours a day," he says. "About two thirds of American children have in their bedroom a TV set, a radio, compact disc player, a tape player. The figures for the household in general [are] about 7 hours plus of television alone, and then several hours more of radio and recorded music and the rest of it. This has become the central way people live their lives, and I needed to understand it. So that's what I set out to do."

Todd Gitlin says those figures vary only slightly in other industrialized countries. And urban dwellers in developing nations are also watching TV, using cell phones and communicating on the Internet in greater numbers. Focusing his critique on American society, Todd Gitlin worries that the media's pervasive reach means attention spans are getting shorter.

"We are dragged from one crisis to another, whether it's the O.J. Simpson case or Princess Diana or Monica Lewinsky or whatever the media craze of the moment is. But then we're off on some other subject," he says. "And we're not very good at paying attention, and therefore we're not very good at governing ourselves and deliberating. I think that's one problem. A second problem is that there's a lot of evidence that insofar as people are spending their time involved with the media, they're not being involved in social organizations, in civil improvement efforts, in political action. They tend when they're on the Internet to connect to people who are more or less like themselves, which means that they're not so much challenging their views as reinforcing what they already think, which is of limited use if we're trying to get people actually thinking about policy."

Todd Gitlin also believes excessive media exposure can affect how children learn. An early introduction to fast-paced video games and television shows may make it harder to adjust to the slower pace of school.

"Teachers I think are rightly fearful that a generation that's dosed on these shows from age one, Teletubbies is aimed at one-year-olds, that a teacher is not going to be able to deliver a historical lesson or a grammatical lesson or a foreign language lesson with the same sort of bright lights and bells and whistles as a Teletubbies, show or Sesame Street, or whatever," he says.

Dan Brooks includes himself among those American young people who grew up with electronic technology. He got his first computer in first grade. Does he ever worry there's too much media in his life?

"My parents keep telling me that," he says. "There are times when you need to go outside and have fun and go on a bike. But there are times when it's a necessary evil."

Todd Gitlin says people respond to the media saturation in a variety of ways. Some become fans, obsessed with a particular celebrity. Or they try to become part of the process, launching their own web sites or trying to get on television themselves. Others make fun of what they see and hear, while still others reject the media altogether, refusing to buy a television, talk on a cell phone or use e-mail. But whatever the strategy, Todd Gitlin says the flood of images and sounds never really stops.

"Some of it is involuntary, whether it's in a waiting room in an airport, or a restaurant try to find a restaurant without a sound track - the billboards, etc.," he says. "So even those who try to control the choices they make in their living rooms are still at the receiving end of the efforts to get their attention."

And what to do about all these messages that seem to say hurry up, get what you want now, and if you're bored, change the channel?

Todd Gitlin says he doesn't pretend to offer any solutions in his book. He simply hopes readers will pause, examine their lives, and think about alternatives to the barrage of media messages that surround them.