Americans have as many taboos about discussing their dreams as any other tribe, according to a University of Rochester anthropologist.

Mary Dombeck says mores determine which dreams can be told to a group and which don't go beyond an intimate friend, spouse or therapist.Dreams that can be told are only a fraction of those that people have, Dombeck wrote in a doctoral dissertation that will be published in late spring. Most are thought of as private, to be shared only with closest family or friends - and usually a woman at that.

Dombeck interviewed 58 people for her study and found that "both males and females said they would be more likely to tell their dream to a woman rather than a man."

Dreams that are OK to share in most social situations are those that have comic features, often involving celebrities. No dreams, she says, are appropriate to share with one's boss or employees. Dreams unsuitable to tell co-workers include those with explicit sexual material, bizarre dreams or nightmares.

"Psychic" dreams - those which prefigure something that later happens in waking life - are seldom related though many people have them. Twenty of the people Dombeck studied for her dissertation, more than one-third, said either they had experienced such dreams or knew someone who had.

The idea that "psychic" dreams could be warnings or could foretell the future reaches back to the ancients. Dreams were understood by many prehistoric peoples to be messages from the gods - an idea represented in classical literature, as well as in Talmudic and Biblical texts. But today, psychic dreams spook people.

To Dombeck, who grew up in a Middle Eastern household where telling dreams was as common as talking about what would be on the table for dinner, the American taboos seem puzzling.

"It's regrettable," she says. "Dreams can be so fascinating."