Feiffer's latest play: another dour one, yet sometimes vivid. A Think Piece. Play by Jules Feiffer. Directed by Caymichael Patten

Perhaps in response to his vision of the times, Jules Feiffer's most recent plays have been pessimistic and even morose. Jake, the disenchanted overachiever of last season's ''Grown Ups,'' alienated not only his family but audiences as well. It closed after a short Broadway run.

''A Think Piece,'' at the Circle Repertory Theater, is even more cheerless. Jake at least experienced the satisfactions of working for the New York Times and of having his first book published. By contrast, the forlornly unfulfilled Betty of ''A Think Piece'' enjoys no such comforting compensations. Betty (Debra Mooney) is a mother and homemaker - a role in which she encounters more frustrations than satisfactions.

Mr. Feiffer sympathizes with Betty and her vague creative yearnings, yet he never succeeds in making her particularly sympathetic. From an amusing first scene in which she vacuums and tidies the family living-dining-kitchen area to the upbeat accompaniment of Bach's Third Brandenburg Concerto, Betty's personal life begins coming apart. And so does ''A Think Piece.''

Mr. Feiffer and director Caymichael Patten use various tricks of theatrical illusion to explore Betty's external and internal world. These include freezing a scene while a spotlight focuses on an isolated conversation or odd moment of fantasizing. Although useful as a means of coordinating kaleidoscopic fragments, the device is not necessarily clarifying.

The play's linear action covers a two-year period and centers on the birthday parties Betty gives for her younger sister Pam (Katherine Cortez). The possibility that sister Mandy (Ann Sachs) may defy longstanding tradition by throwing the second party herself provides ''A Think Piece'' with its climactic crisis and aftermath.

Meanwhile, Mr. Feiffer devises exchanges and confrontations to throw light upon Betty's relations with her unmarried careerist sisters; long-suffering husband, Gordon (Andrew Duncan); pre-teen daughters, Ginny and Lulu (Tenney Walsh and Samantha Atkins); and the family's patiently amiable dog, Zero (Patches). Betty's desperation and sense of unimportance mount as crisis follows minor crisis.

Since Mr. Feiffer does not describe ''A Think Piece'' as a comedy, its low laughter quotient should probably be taken for granted. But notwithstanding the fact that his immediately recognizable characters are believably and even vividly protrayed by Miss Mooney and company, the new work offers little in the way of fresh insights or deepened understanding of Betty's matronly plight. Regrettably, ''A Think Piece'' is a dour play.

Scene designer Kert Lundell's attractive East Side Manhattan apartment setting was lighted by Dennis Parichy, with costumes by Denise Romano and sound by Chuck London and Stewart Werner.