Probably it’s simplistic to think of a choreographer’s career as variations on a theme, but the splendid retrospective " Trisha Brown: Dance and Art in Dialogue 1961–2001, " which opened last weekend at the Addison Gallery of American Art in Andover, showed how important visibility is to this dancemaker. From her first perceptual experiments to her current explorations of stage space, Brown has probed the issues of seeing — how we see the dancer, how the dancer sees herself, what it means to see and be seen. The Addison show, plus several performance events last Saturday, opened up many of postmodernism’s old questions again, supplying a healthy jolt to the mind as we start out on a new season.

Curated by Hendel Teicher, the exhibition occupies the entire second floor of the Addison Gallery on the Phillips Academy campus — 10 separate spaces filled with graphics, objects, videos, sound, and installations that document Trisha Brown’s dance. Brown and company were on hand Saturday for a morning talk and an evening performance, and a group of students performed two of her early pieces during the afternoon. The show will run here until January 5, then move on to the co-sponsoring Tang Teaching Museum at Skidmore College and institutions in Houston, New York, and Seattle.

Despite its title, the show pretty much skips over the first decade of Trisha Brown’s career, beginning with her so-called equipment pieces around 1969. Before that she took part in the Happenings and was a mainstay of the Judson Dance Theater and Yvonne Rainer’s improvisational Grand Union collective. The cross-disciplinary events of the early-’60s avant-garde were highly visual, non-linear, hallucinatory, as dancers worked with artists, filmmakers, and poets to upend the fundamental assumptions of performance and invite new definitions.

There was no recognizable dance, but there was a lot to see: props, designs, film and graphic projections. Often the event took place in some non-theatrical environment or incorporated elaborate constructions that the performers had to grapple with. In some way, the outlandish sets and designs, the surrealistic costumes, the bizarre behavior forced the audience into either making up a rationale for what was clearly irrational or sitting back and enjoying it as spectacle.

Brown was interested in three things, I think, in those days: making demands on the performers that didn’t require conventional dance technique; creating formal structures, like little games or tasks, that would facilitate movement exploration; and proposing situations to the audience that would jar us out of our usual viewing habits. By the beginning of the ’70s, she was doing her most famous equipment pieces, Walking on the Wall, Man Walking Down the Side of a Building. These and less spectacular ones like the Leaning Duets — where partners connected by loops of rope leaned away from each other or against each other, trying to fall or not to fall — were shown at the Addison in photographs and generous film clips projected large in an empty room.

In the gallery devoted to the early work, one example from this series was performed live by three students. (Unfortunately, no program information was given about these young women, or about how they learned the piece.) Floor of the Forest (1969) takes place in a rope grid like a cargo net that is suspended about five feet off the floor. Pieces of clothing are threaded in the net, and the dancers move across it, wriggling in and out of the sweaters and shorts as they go. They have to twist into unusual shapes, balance and rebalance their weight, in order to negotiate the odd environment. I saw this piece in a gym at NYU in 1971, when the net was hung higher and a rummage sale was taking place underneath. The performers were like animals, silently moving above us in a jungle canopy. When the performers are at eye level, it’s an endless fascination to watch them pushing the limits of their own trust and flexibility.

Brown found simpler ways to elicit movement adaptations during this same period. In Roof Piece, dancers telegraphed a sequence of big gestural moves from one to another along half a mile of downtown New York rooftops. No spectator could see the whole piece, but when the sequence reached the end and was relayed back the other way, you could see how the shapes decayed as each person picked them up and copied them. In the Sticks series, they had to balance long bamboo poles with certain restrictions, like moving from sitting to lying down while touching the pole of another person. Some of Brown’s own drawings are included, and she sets up similar tasks for herself there. She draws her right hand with her left, her foot with the other foot.

Becoming more interested in pure movement, Brown worked variations on the device of Accumulation, building a dance one gesture at a time. With each addition, the dancer repeats the whole string of gestures until they add up to 30. Naturally, this results in a lot of repetition and the possibility of slippage — corners get cut here and there, little bits get speeded up, hesitations and tiny distractions break the continuous flow of the sequence. In a courtyard at the Addison Gallery, five young women lay on the ground and performed Group Primary Accumulation, doing the identical sequence but with minute individual differences of timing, phrasing and placement.

Around 1975 Brown, along with many of the postmoderns, started taking her experiments into the mainstream with a touring company. She developed a specialized dance technique and fully designed choreographic productions meant for the stage. The Addison show concentrates on five visual artists who’ve worked with her since that time as the company has expanded and prospered.

She met Robert Rauschenberg in the Judson Dance Theater days, and he’s contributed scenic elements to at least five of her dances. Most of his designs added or created some illusionistic problem: his big black-and-white photographs of clothes lines, boxcars, street lights, oranges, that cycled across four huge panels behind the dancers in Glacial Decoy (1979); the translucent costumes and side curtains for Set and Reset (1983); the lighting instruments and microphones mounted in steel frames that activated light and sound when the dancers passed through electronic-sensor beams in Astral Convertible (1989).

There was a room of Donald Judd’s austere but minutely varied minimalist boxes and woodcuts. He made the color-field backdrops for Son of Gone Fishin’ (1981) and Newark (1987). Nancy Graves’s squiggly, complicated, brightly colored " land forms " inhabited Lateral Pass (1985), and Fujiko Nakaya’s fog installation obscured the stage and became a screen for the dancers’ projected shadows in Opal Loop/Cloud Installation (1987).

In the evening concert, Brown’s solo If You Couldn’t See Me (1994), with music and costume by Rauschenberg, played another Brownish trick on the audience’s eyes. She danced the whole piece without showing her face in our direction. Her articulate back, her easy-swinging arms and legs, could belong to a much younger woman; she’s about 66 now. But I also started fantasizing about what the dance would look like if I were sitting at the back of the stage instead of the front. Well, what is back and front anyway, Brown might ask.

Terry Winters’s drawings in the gallery seemed to get denser the more I looked at them. Rhythmic swirls and tangles were laid down on forests of parallel lines or curves, and underneath or behind those were smaller, busier shapes, and even graph grids. Two drops for El Trilogy (2000), which was performed by nine company dancers, replicated these drawings, one in giant size and 24 of them in neat rows. Winters also contributed a tree of brass cymbals in gradually diminishing sizes top to bottom.

The dance, with modern-jazz-bebop music by Dave Douglas, was created in three big blocks over a couple of years and still looks like three separate dances, with two solo interludes performed while the crew changes scenery.

Since Brown began making stage pieces again — music appeared even more recently — her work has looked less organically conceived to me. If there’s a structural scheme, it’s less evident. She explains in the exhibition panels how scene designs prompted her to think about the movement in various pieces, and you can see in her dancers’ movement her fascination with illusion, transparency, layering, lightness, levitation, levity. Three men lift one another, blurring the moment of lifting and leaving the ground. There are unison duets where one dancer is directly upstage of the other instead of by her side. In a downstage-upstage line-up, movement proceeds through the group in a wave, like something in a Busby Berkeley movie.

But El Trilogy is a long dance to take in after the other provocations of the day. I lost my way in tracking it, through the stretches of flinging arms and soft pivotings and gesturing and line-ups. Finally the piece seemed like a perpetual-motion machine that was changing all the time and somehow at the same time not changing at all.

The Addison Gallery is issuing a handsome catalogue of the show, and there will be further performances. Trisha Brown’s career needs revisiting and more exploring, and it’s not done yet.