Perhaps because its architecture is so dramatic, Chicago's drama seems undramatic.

During the recent fifth annual meeting of the American Theatre Critics Association, the six new plays to which one was so hospitably welcomed seemed like shrunken littles toes after heady daylight hours, on shank's mare, exploring this city's fabulous buildings.

For here, especially along Michigan Ave. and the Loop, are buildings of unmistakable, individualistic character, some dating back nearly a century, reflecting Louis Henri Sullivan, Frank Lloyd Wright, Mies van der Rohe and others of what's been dubbed The Chicago School.

Around 5 p.m., for instance, office workers, mod from heels to hair, tumble out of an 11-story downtown building, the Rookery, designed by Burnham and Root in 1886, its street lobby remodeled in 1905 by Wright. What changes in dress this whimsical lobby has seen! It is a building whose vigor remains awesome in the late 20th century; and if classical drama seems not to even breath in Chicago, its architecture throbs with life.

The Adler and Sullivan Auditorium building of 1889, its renovation recently celebrated, is but one of scores, not one like another and all obviously above 50 years old, along Michigan Ave., rewarding the stroller's keenest scrutiny, a quickening way to approach, on the lake side, the splendors of the Art Institute of Chicago, now observing its 100th year.

The Institute also is the home of the Goodman Theater, a 1925 addition on the lake side of the 87-year-old building. Here the 50-odd attending critics gathered for the first event of their meeting.

This was the first of several "world premiers," and its author is the much admired David Mamet, whose "Sexual Perversity in Chicago" and "The Duck Variations" put him on the national map and whose "American Buffalo" and "A Life in the Theater" have won major awards.

Mamet's new work is "Lone Canoe" and concerns two British explorers, and John Fairfax and Frederick Van Brandt. The latter has returned to this northern outpost to discover what happened to his fellow explorer, Fairfax, who, it develops, has taken an Indian wife and is living happily with her small tribe.

Through lies, VanBandt prevails on Fairfax to return to England and clear his supposedly dishonored name. What appears to be a violent murder also appears to be symbolic, for the murdered Indian leader, or his symbolic clone, later turned up intact, a matter I had no trouble accepting as a symbol, for symbolism is a Mamet essence.

Staged by Gregory Mosher, who originally guided "American Buffalo" and "A Life in the Theater," the production is measured, as if by metronome, and also includes a mixed score by Alaric Jans, who darts from evoking the woodlands to a Gilbert and Sullivan jig. All this comes through as primitive mod, as though Grandma Moses and Geoffrey Beene had collaborated on a stage production.

Unlike Manet's previous works, "Lone Canoe" drew impatient audience and critical response, the first chuckling in quite the wrong places. Linda Winer, in the Tribune, and Rick Kogan, in the Sun-Times, the next morning expressed controlled dismay and grave disappointment. The play wright was so displeased by the reception that he cancelled a planned panel discussion with the visiting reviewers.

I cannot say I was disappointed, for Mamet always has seemed to me an over-rated dramatist, his scenes usually limited to two characters at a time, his narrative structure close to nil and his symbolic meanings preventious if not outrightly preverse.

The next afternoon, Chicago's noted Second City satirists commented on Mamet's debacle. Using the first line of his play, VanBrandt's "I am lost" and the Indian heroine's "I am alone," Second City showed that 15 years have not dulled its satiric essence. "Lone Canoe" veterans broke up.

A visit to Second City's 58th revue, "Freud Slipped Here," revealed that though the little theater has expanded into second companies, it remains a creative organization, playing its topical skits, some brief, some merely short, with alert dispatch.

Optioned for New York is William Alfred's "The Curse of an Aching Heart," presented by the St. Nicholas Theater Company. Author of the long running "Hogan's Goat," Alfred again uses old Brooklyn as his setting but for a far more mellow play.

To a score by Claibe Richardson, who provided music for "The Grass Harp" and "The Royal Family," Alfred uses the Irish strain of the New York borough for his tracing of two marriages to an Italian unsettled an Irish girl's sole family tie, an old man's stubborn pride providing the heart-tug of his three-part, no-interval work.Firmer focus may help.

A fragile mood is the work's desiderata, so far but partially achieved. Should a more expansive staging occur, an achieved mood may quicken this novelty.

Less hopeful is Richard France's "Station J," at the Body Politic, a company, as its name implies, dedicated to influencing our minds. But this over long, scattered work about internment of Japanese-Americans during World War II is far too inclusive and disoriented, alerting only the desire for it to be over and done, a sadly desultory experience.

Inspired by newspaper columns of Chicago's Bob Greene and Paul Galloway, "Bagtime" has been moved to the lavish Drury Lane Theater at Water Tower Place after a sold-out run at the modest Wisdom Bridge Theater. It's a musical about one Mike Holliday, a supermarket "bagboy," the fellow who fits groceries into paper bags.

Mike is an odd sort of hero, youthful, divorced, innocently appealing, who becomes a Chicago personality by unintentionally recounting his sexual adventures on TV.Within a few days he appears to have bedded four, or possibly only three, females, one of whom is the mother of another.

Alan Rosen's book, Thom Bishop's lyrics and Louis Rosen's music are carefully crafted for Chicago, using personalities, locales, the White Sox and the Bears. This local appeal works well enough on the home turf, but it will hardly bear transplanting. Seating 1,152 in the height of Belle Watling decor, the Drury Lane and its present tenant seem a cheerful spot for Chicagoans.

Intensity of performance is the mark of the Organic Theater, where "The Little Sister" has been a view, a spoof on one of Raymond Chandler's Philip Marlowe detective yarns. The attraction is adapter-actress Carolyn Purdy-Gordon in three quick-change roles, but one departs musing on the hold that old movies seem to have on today's theater people, a recurring, too-cute pervasiveness.

At the larger, commercial theaters are Hume Cronyn and Jessica Tandy, selling out again in "The Gin Game," and Broadway's touring "Dancin'," about to make way for "On the Twentieth Century," with Rock Hudson as Imogene Coca's new costar.

An association of theater critics is, to be sure, an invitation to chaos, for critics by their nature believe those with opposing viewpoints, however minute, to be idiots, illiterates, insane or so hopeless wayward as to make serious discussion futile.

Thus, a smiling panel of nine Chicago theater people struck one as trained seals facing what looked to them like unleased lions but were actually cautious, harmless cats.

The seals remarked that each of their theaters has its distinctive personality, then elaborated on "commitment," "women's theater," - all with such uniformity of words and images that for this listener each theater seemed identical to every other one. Why are theater directors such untheatrical speakers?

It seemed revealing that when a noted professional actor in the audience, John Hoyt, mentioned that he was performing in the Chicago suburbs, he was treated, by panel and audience alike, as if he had a fatal disease. Len Alexander, general manager for the Loop's two Shubert houses, both hosting larger audiences than all the other theaters combined, also was received in that silence that suggests misfortune beyond mention. Must theaters all be non-profit and make-shift to command respect?

Genial humor from tamed lions prevailed under association president Lawrence DeVine, of the Detroit Free Press, whose task may have been eased by the absence of three-quarters of the 200 members.

Besides the announcement that this year's Tony to a regional theater, an annual recommendation of the group, would go to San Francisco's ACT - American Conservatory Theater - there was another professional action. Through nomination by the Philadelphia Bulletin's Ernest Schier, the group's first "Distinguished Criticism Award" was accepted by Claudia Cassidy, the singular and celebrated critic of the Chicago Tribune. Introduced by her successor, Linda Winer, the perky 78-year-old mentor of Chicago culture heard a reading by the Boston Herald American's Eliot Norton of her prescient, beautifully phrased first review of "The Glass Menagerie."

Cassidy's 1944 championing of the Tennessee Williams drama at a time it seemed about to expire in Chicago became the highlight of the three-day meeting, reflecting how, at the right time, in the right place, a sensitive critic can be of vital value, the silent, common aspiration of perceptive critics whatever their disavowals of power. CAPTION: Picture, Norman Snow as Sir John Fairfax in "Lone Canoe" at Chicago's Goodman Theatre: A primitive existence.