Dr. Joyce Brothers is posing for a picture.

She modifies her make-up, adjusts the pale hair, withdraws the brown sunglasses, analyzes the polished smile, and rests her chin ever so lightly on her hand.

"After all this time on the air," she says in a pale voice, "I've learned by trial and error not to push my face around."

Sometimes Brothers is described as a psychologist, sometimes as a TV personality, and sometimes as a celebrity. Now she is asked how she would describe herself.

She smiles and smooths an invisible wrinkle from the pink silk dress. "Why not just say 'darling person?'" she says.

For over 20 years now, Brothers has been ministering to the national psyche in print and video, telling everyone what she thinks about everything and getting paid a bundle for it. Somewhere along the line she turned into Middle America's psychological sibyl and the question is how.

"I won't attempt to define myself," she says. But she will say that scarcely a day has gone by in two decades that she has not been on the air in some form or another dispensing advice, and that in the ever-shifting lexicon of teen-age slang the word for "psychologist' among some adolescents is "Joyce.' She ranks among the top 10 admired people on all sorts of polls, she notes, and believes that we have her pioneering efforts at mass-market counseling to thank for the televised advice, radio call-in programs and telephonic consulting services available these days.

Brothers, who lives in Fort Lee, N.J. during the week, and on her New York State farm on weekends, has a syndicated newspaper column seven days a week. And a daily radio show. And a monthly column in a woman's magazine. She does two pieces a week for a television station in Los Angeles and, every three months, a "mini-documentary" that runs five minutes a day for five days.

In March there will be available for syndication 65 half-hour television shows featuring Brothers discussing 65 different topics. And in New York, you can dial a special number courtesy of the telephone company and get 57 seconds of Brothers talking about how to quit smoking, lose weight or deal with impending pregnancy. At least 40,000 people a day dial the number, she says.

"There is a lot more searching for answers, these days," she says. "And a lot more answers, too. But we're missing friends and kinship roles. So you rent a friend. Like Dr. Joyce Brothers."

Or you read one of her books. Like "Ten Days to Successful Memory," or "Woman," or "The Brothers System for Liberated Love and Sexuality," or "Better Than Ever." Or her latest, "How To Get Whatever You Want Out of Life."

The daughter of two New York lawyers, Brothers went on to get her PhD in psychology from Columbia in 1953, and she started getting what she wanted out of life early. She got "the fame and fun and money of this new-to-me world of mass communications" by winning $125,000 on the TV game show, "The $64,000 Question" in 1955 by becoming an expert on boxing. Three years later she had her own television show and has never left the air.

She talks about "just everything. There's nothing that isn't grist for my mill." She talks about what makes men attractive to women and what's in a person's name. She talks about anxiety with the Denver Dental Association, and the psychology of color with a carpet company and American life styles with Armstrong Cork.

She travels with a "big bag on wheels" that is stuffed with all the reading material from which she gets her grist and has four college girls clipping, filing and cross-indexing it all back home in New York. And in over 20 years, she says, she has never "made a misstatement of fact."

And in between, she takes a look at America's id, ego and superego on the lecture circuit. "There is much more concern about the economy," she reports. "And yet people feel very satisfied with their lives."

She is concerned, however, about "the amount of selfishness in the 'Me Generation.' Everybody in the '60s wanted to change the world.

"But society was like an elephant," she says, "it just stood there and smiled and didn't budge. Now people are concentrating on themselves, they are worried about their own goals and how to achieve them."

This is not very healthy, Brothers says. But then again, she has just published a book with chapters like "The Manipulative Handbook" and subchapters like, "How to use fear to clinch a sale."

But how bad can it be if Dr. Joyce Brothers is out there telling her readers how to feed the old ego machine, and get rich and/or powerful no matter what it takes?

"Well," she says, "I do try to point out that some of the things people think they want aren't all they think they are, but if they want them anyway, there are certain psychological tools that will help them get them.

"You can't expect people to be altruistic all the time, and you can't live their life for them. Besides, I'm quite satisfied that getting what you want out of life doesn't mean hurting other people."

Brothers has her own ideas about what she would like to get out of life 10 years from now. "I'd like to run for Congress. Coming from a family of lawyers, [her sister is also a lawyer] I see how lawyers are needed to get people out of trouble. But that's a negative approach. I think Congress could use more humanists." Unfortunately there are liabilities in the vision. "Once you run for office, people can throw all the mud they want at you. It takes a lot of courage to put yourself up front like that."

But that is 10 years from now. Until then, Brothers has her work and her farm and her 24-year-old daughter, Lisa, a doctor, and her 29-year marriage to Milton Brothers, who is also a doctor. Speaking of years, Dr. Brothers is asked how old she is.

"I'm fine, thank you," she replies.