REAL LIFE-K-B Baronet West, K-B Cerberus.

The preamble to "Real Life" first states that the Public Broadcasting System filmed in 1973, a 12-part series on "a real family's life" called "An American Family." Then it quotes the late popular anthropologist Margaret Mead as calling the idea "as new and as significant as the invention of the drama or the novel - a new way in which people can learn to look at life by seeing the real life of others interpreted by the camera."

We were all to learn very quickly how "real" the Pat and Bill Loud family was, once it became conspicuous. In one ludicrous installment after another, reports outside the film itself informed us how "ordinary people" take to the silly life we consider ordinary for celebrities. The parents split up, the mother wrote a book, the son declared he was a homosexual and so no, all with Margaret Trudeau fanfare and faith in the importance of their little antics.

Perhaps that was all the satire that new and significant idea needed. But somebody had to settle the hash of Margaret Mead and othe practitioners of "behavioral science" for lending solemnity to such goings-on.

"Real Life," which does a band satire of "the people who came to film that family and the effect they had on each other," also, in a more gingerly fashion, goes after those who inspire this sort of thing with "the science of human behavior."

It's easy enough to impale a California-drenched moviemaker who keeps shouting "Be yourself" and assuring people that their worst blunders "maker you look good" because they are sincere - and who then cracks because they stop talking for a while. Albert Brooks' performance as a comedian named Albert Brooks, and his writing (with Monica Johnson and Harry Shearer) and direction alternate the subtle with the unsubtle.

The film is at its surest when going after filmmaking, with idiotic documentary narrations, the visual cliche of happiness being in slow motion, the dumb questions of television news interviewing. Charles Grodin and Frances Lee McCain perfectly represent real people as we know them from television commercials.

But the film's most delicious moments are when the Institute for Human Behavior is exposed. There are the "scientific tests" for finding out what family would make a good documentary subject. There is the professional manner of the psychologists as they desperately try to keep feeling superior to the filmmakers who are doing their work. Finally, there is their truly more sophisticated knowledge of how to protect themselves legally from their subjects.

Brooks seems to be trying to protect himself from full responsibility for this devastating attack by putting so much of the blame on the character he plays. J.A. Preston, as a black psychologist, has the only dignity in the whole film when he quits the project but the dramatic evidence is against him, since he agreed to participate in the first place, and his heroism is quickly deflated by having him write a quickie book about the experience.

And there's a nice final touch, when historians in the audience are offered a toll-free number to call for further information.

If not new and significant, it's at least a funny attempt to pull off the trick of holding a mirror to our hall of mirrors. CAPTION: Picture, ALBERT BROOKS AS ALBERT BROOKS, HEAD OF THE FILMMAKING GROUP IN "REAL LIFE"