ART : COMMENTARY : Two Artists and the Meaning of Identity : Bruce Nauman and Mike Kelley mix their media, neither relying on traditional painting or sculpture in their pursuit of artistic identity.

A principal convention of mod ern culture says that true art asserts individual identity, which is hidden behind a surface facade that is, in fact, a mere illusion. So, the artist’s job is to go beyond outward appearance to reveal that hidden self.

Two concurrent museum exhibitions not only make for an extraordinarily strong summer season in Los Angeles, they also demonstrate how this established convention has been broadly rejected in the work of two of the most highly regarded artists working today. For them, the idea of artistic identity isn’t what it used to be.

At the Museum of Contemporary Art, the retrospective exhibition “Bruce Nauman” rousingly confirms the widely held belief in the preeminent stature of the 52-year-old artist. Meanwhile, at the Los Angeles County Museum of Art, much the same response greets “Mike Kelley,” a witty and compelling survey exhibition of an artist 13 years Nauman’s junior. A sustained level of excitement and excellence marks the careers of both.

While differences between their specific artistic interests are considerable, important points of convergence between them can be identified. Nauman and Kelley both evince a strong interest in language and humor as engines for driving visual art, while neither relies on traditional painting and sculpture to do the job. Instead they mix their media, using whatever materials are appropriate.

Perhaps most noteworthy is the relationship of their work to the modern convention concerning individual identity. A pronounced feeling of free-floating emptiness lurks in both exhibitions--not an emptiness in the negative sense of an art without substance or weight, but one that denies the traditional distinction between a deceptive and shallow “outside” that’s been torn open to reveal a profound “inside” secreted deep within.

One way to think of the traditional distinction is to cite another specifically modern and related invention. Freud asserted that although an individual’s identity is socially constructed, not just naturally produced, the form it takes is conditioned by the inner psychological self. Peeling back encrusted outer layers will uncover true identity, rather the way the spiky leaves of an artichoke protect its tender innards.

Think of Surrealism. The idea that rational thought keeps us separate from productive sources deep within the subconscious mind led to a high regard for the creativity of children, primitive people and the insane, who supposedly aren’t disconnected from the deep well of spontaneity within.

This conception of identity--whether in Freudian psy chology or abstract art--is based on a belief that a powerful center guides and gives meaning to experience, which is more commonly known by its vague and amorphous periphery. By contrast, Nauman and Kelley make art that dismisses this entrenched Modern idea as false.

Rather than revere childhood, Kelley elevates to prominence the conflicted years of pimply adolescence, extolling the period when the supposed disconnections from inner harmony run amok. His celebrated sculptures made with soiled, tattered stuffed animals and plush toys refuse to idealize visions of childish purity. And a pair of comic drawings of a two-story outhouse makes wicked fun of Freud’s explanation for the youthful origins of creativity.

Nauman’s repeated use of fragmentary body parts, both human and animal, attacks holistic integration. Other sculptures, such as the funny concrete lump of “A Cast of the Space Under My Chair” and the sickly, glowing green “Neon Template of the Left Half of My Body Taken at Ten-Inch Intervals,” are designed to give form to emptiness or bodily absence.

In the four-part film, “Art Make-Up,” white, pink, green and black body make-up is applied sequentially to Nauman’s face and naked torso. His outward appearance is impassively altered, while the exposed artist’s anonymity is colorfully secured.

Nauman’s and Kelley’s work, like that of several other artists, plays against the idea that a substantive center shapes the illusive periphery. For them, the periphery is quite as deep and complex, and just as meaningful and real.

Nauman and Kelley are both Midwesterners. (Nauman was born in Ft. Wayne, Ind.; Kelley grew up in a suburb of Detroit). After college both came to the West Coast for graduate school and, when they finished, both made the fateful decision to stay in California.

Nauman worked in Los Angeles during the decade in which his precocious artistic voice matured into full resonance (1969 to 1979), before moving to rural New Mexico, where he lives today. Kelley has lived in Hollywood and Eagle Rock, ever since his 1979 graduation from CalArts.

For most of the 20th Century, and especially after World War II, the lure of New York has been strong for young artists. By the time Nauman and, a decade later, Kelley came along, it still was.

But their relationship to the center of the art world is revealing. Both recognized the significance of Manhattan as a powerful artistic milieu and as a major marketplace for contemporary art, and both began to show in commercial galleries there early in their respective careers. (Coincidentally, each was a youthful 26 when he had his first New York solo show.) However, neither artist saw any compelling reason to establish a studio there, as a base from which to live and make art.

The art of Nauman and Kelley has ended up a touchstone for their respective generations, both in the United States and Europe, because something about the decision to work in L.A. rather than New York fit seamlessly with the developing aesthetic position of their art. In renouncing the old idea of a split between a deep and meaningful center and a shallow and deceptive periphery--a split that has been undone by mass culture--they began to chart a slippery new terrain in which everyone, everywhere, resides.

* “Mike Kelley,” Los Angeles County Museum of Art, 5905 Wilshire Blvd. Hours: Wed.-Thurs., 10 a.m.-5 p.m.; Fri. 10 a.m.-9 p.m.; Sat.-Sun., 11 a.m.-6 p.m. (through Sept. 11). (213) 857-6000.

* “Bruce Nauman,” Museum of Contemporary Art 250 S. Grand Ave. Hours: Tues.-Sun., 11 a.m.-5 p.m.; Thur. 11 a.m.-8 p.m. (through Sept. 25). (213) 626-6222.