San Francisco — You might call Herb Dordick one of the doubting Thomases of the information age. Thirty years ago, Mr. Dordick, a professor at the University of Southern California's Annenberg School of Communications, was a telecommunications champion: He wrote a number of studies predicting a marvelous future for cable TV. But years of studying how people do, and do not, use sources of information and communication technology have given him a more balanced view, one considerably at odds with the hyperbole that has become common recently.
Sitting on his porch in southern California, a cordless telephone within reach, Dordick drew on his considerable experience in an attempt to put recent developments like the home computer into perspective.
''I began thinking about this several years ago. During student-faculty consultations I had six students in a row who were studying videotext (systems to send the printed word over the television).
''This was so extraordinary, that finally I asked one student, 'How do you know videotext isn't just another Hula-Hoop?' The poor kid almost fainted,'' he recalls with a chuckle.
Shortly after this, he got a call from someone who had read his old papers on cable television. The person asked why his old predictions weren't happening, and he couldn't explain it.
As a result, Dordick began gathering statistics and studying the way people use various sources of information and communication. He has assembled a number of little-known facts that suggest that the nation will not be overrun by computer networks as rapidly as many are predicting:
* Libraries are used by only 10 percent of the residents within their service area.
* A third of the way down a news column, 50 percent of the readers quit; by half-way down, 80 percent have gone on to another part of a paper.
* Before-and-after studies of companies that have converted to electronic filing systems have shown that, although 80 percent of the professionals say they intend to use the system, only 10 percent use it more than once.
* Employees at one large company that went to an electronic mail system (sending messages by computer) were so enthusiastic that the system was soon saturated. But when the company offered a system that records and relays spoken messages, they virtually abandoned the electronic mail system.
For reasons such as this, ''I don't believe the computer will have the revolutionary impact that the automobile, the radio, the telephone, or the television have had,'' Dordick argues. The 10 percent of the people who use information sources heavily today will continue to do so, using the new technologies as they become available. But the vast majority of people will continue to rely on traditional sources of information: friends and acquaintances, newspapers, magazines, television, radio, and the telephone, he foresees.
''Most people's home computer will not be an Apple or an IBM, it will be a telephone with a computer terminal,'' Dordick says. This will allow people to tap into computerized information sources to a limited extent. But, as the electronic mail example above illustrates, people will probably prefer talking to telecommunicating.
Many people underestimate the importance of the telephone, which Dordick says is the ''least researched piece of telecommunications equipment.'' From research he has been involved in, it is clear that the telephone plays a major, and largely unrealized social role, he explains. For instance, he has found that teen-agers consider the telephone second only to face-to-face meetings as a source of entertainment: well ahead of television and radio.