It’s a simple question without a simple answer: Why do we look at portraits and self-portraits of people we don’t know?

In fact, that question triggers others, more than it does an answer: Can we imagine a life from looking at a picture? And when we are intrigued by a face, do we make an effort to find out more about that person?

For some people, the pleasure of a portrait may be more basic: They just like to admire the skill of a painter who can depict someone well. Or is the ongoing fascination with portraiture an oblique form of narcissism?

For most viewers, it’s probably a mix of these interests, along with a few others. And when the work is a self-portrait, there is the added fascination with what the artist wants to reveal or say about him or herself.

If you visit the Lux Art Institute’s current exhibition, “Susan Hauptman,” questions and issues like this are to the point, since Hauptman is an artist for whom self-portraits are at the core of her work. You might find her androgynous image of herself unconventional and unsettling, but you are likely to be engaged nonetheless.

She does them all in charcoal and pastel, some on a large scale. And whether you take a favorable or unfavorable view, you can’t help but marvel at her skill. Hauptman combines a realism bordering on the photographic that is then softened considerably by her choice of medium. The clarity of detail in her face is acute, right down to a small crease near the mouth or a mole. But skin itself can look as soft as silk, in the way she lays down charcoal.

As with each exhibition at the Lux, the artist arrives along with the show, adding a work to it that is produced during the first weeks of its display. Hauptman, an acute perfectionist who produces about three to four finished works a year, brought a self-portrait in progress with her but decided, after some days, that it would never be completed; she erased it. In her second week on location — Hauptman lives in New York — she revised “Doll” (2001), one of her still lifes on view, shifting one object from gold to near white. Seeing the finished form, it seems like time well spent.

The still lifes are just as virtuosic as the self-portraits, more amiable and less edgy. Hauptman herself is a diminutive and gently charming woman. The Hauptman in her drawings — or it could be more accurate to say Hauptmans — are usually stern or somber, and have a more severe look with head shaved or hair cropped extremely short.

Within these parameters, Hauptman’s identity and look shifts considerably from picture to picture. So does her costuming. In the stately “Hair Self-Portrait With Dog” (2001), the largest selection at 94 inches tall and 40 1/2 inches wide, she wears a long dress with a pronounced geometric pattern. She faces the viewer, while a dog poses in profile. In the haunting “Self-Portrait (With Branch)” she wears a simple dress, its design suggestive of a girl or teenager, with a black bird on a black branch. In “Self Portrait,” she is more formal, wearing a kind of evening dress. In “Self Portrait (La Perla #1)” (2006), she wears a see-through baby doll nightgown.

These shifts in costume are dramatic, as if she were trying on different identities. This is a familiar conceit in the postmodernism that emerged the 1980s and 1990s, done most famously by Cindy Sherman in photographs in which she is artist and subject.

Sherman rarely looks like herself. She is costumed in wigs and radically different outfits; posed in wildly different settings. Hauptman, like Sherman, is picturing the notion of complex and fluid nature identity. But where Sherman pictures female archetypes in film, myth and other cultural sources, Hauptman is visualizing buried parts of the herself as much as enacting a costume drama.

At the same time, she is slyly toying with social conventions. In “Self-Portrait” (1995), in which she is dressed like a ballerina, we expect the artist to have long hair and perhaps a sweet expression; instead, we’re greeted by a pensive face and masculine or butch hairstyle. And just to complete the set of mixed visual messages, Hauptman lifts her arms in a sweet, feminine way, as if she is about to dance out of the field of the picture.

She seems to be different ages in different paintings, too, looking adolescent in Self-Portrait II” (2002), in which she sports a clown collar and little feathered cap, and closer to her age in “Hair Self-Portrait With Dog,” made when she was in her early 50s.

Props aren’t a big element in her self-portraits. Only “Hair Self-Portrait” has any: a pair of beach balls, one in color and one in black and white. But rendering objects is clearly as important to her vision of image-making as picturing herself.

The two bodies of work are most obviously linked by wonderful drawing. They are equally connected, though, by the intense attention to detail. The same remarkable eye for skin or cloth spills over to a picture like “Still Life (With Flowers)” (2004), in which a black anthurium (with a splash of red) floats high in the picture, along with a more rounded white flower. Below is a vase with a little courtly image of a couple on its surface. This could be a veiled sort of portrait of Hauptman and her husband. The anthurium has a phallic stamen and the white blossom is more feminine. And, the couple on the vase reinforces this theme. But, as with all successful still lifes, it’s the life of the objects in the picture that matters first; symbolism comes second.

Hauptman doesn’t need color to make them things thoroughly convincing. The grapes are perfectly executed in “Still Life (With Small Pitcher)” (2004) and “Still Life (With Plastic Concord Grapes)” (2005). So is the crystal or glass dish that holds them. In these pictures, mood more than meaning seems to be what she’s after. They have that wonderful tranquillity that some artists can achieve with the genre.

“Doll” (2001) is a bit different. It’s a mystery picture. Why is this aged doll keeping company with a bowling pin? The pin might be a surrogate for a human figure. The presence of the beautifully drawn doll makes that idea plausible. Still, interpretation here seems wide open.

In truth, you hardly care. The individual forms are so fully realized that you get lost in the quality of the image. That is something to savor.

And while seeing her show may not reveal new answers to essential questions about the appeal of portraiture, they affirm the enduring power of the drawn portrait. It won’t be disappearing anytime soon, no matter what new technologies emerge.