Years ago, Michael Apted made a documentary, "7 Up," about British 7-year-olds from different walks of life. Later, he had the notion of catching up with them every seven years, to see what had become of them, and the (perhaps interim) result is "28 Up."

The concept, unfortunately, is less intriguing than it first seems. Some have had their dreams dashed, some have fulfilled them, some have exceeded them, and some have substituted new dreams for old ones (a would-be jockey now drives a cab and aspires to the stage). Some seem to be prisoners of their class and upbringing (the particular ax Apted is grinding), but not all.

All have gotten older.

That's said only partly in jest -- there's a kind of home-movie element to "28 Up," the fun of seeing people grow up before your eyes. And it's interesting to watch how, almost without exception, the subjects grow snotty, hostile and/or affected around the age of 21.

But the gimmick grows stale quickly, and what's left begins to resemble an uncomfortable cocktail party. The problem lies in the questions of the interviewer, which tend toward small talk: What was the greatest moment of your life, how (in the case of couples) did you meet, what attracted you to one another and so forth. "28 Up" only underscores what has always been puzzling about documentary films: why more journalists who are experienced in framing this kind of story don't make them.

It's hard to separate the cute from the vicious in children -- Truffaut from "Lord of the Flies" -- and the best parts of "28 Up" are the clips from Apted's original, black-and- white documentary, in which the children, without self-consciousness, reveal exactly the points about British society that Apted is trying to make. That may be the kindest way of saying that those points are, uh, childlike in their simplicity.

28 Up, now playing at the Inner Circle, is unrated and contains some mild profanity.