Rapid changes in American society during the 20th century have led to the current lack of direction in modern architecture. Ada Louise Huxtable, architectural critic for The New York Times, told a capacity audience of about 300 at Longfellow Hall yesterday.

In the first annual lecture of a new series established by the Radcliffe Chapter of Phi Beta Kappa, Huxtable, here for a two-day visit, said architects today no longer believe they can improve society through better housing. "We're addressing the failure of a moral vision," she added.

Earlier in the century, she said, architects attempted to create the ideal home design which would resist the trends of fashion. When they found that their designs failed to take into account the nature of economy, which is based on built-in obsolescence, most turned to the production of "a set of aesthetic exercises," she added.

Huxtable, who won the 1971 Pultizer Prize for criticism, said that today architecture has no motivating vision and so there are no great architects. "The age of masters is finished," she said, adding that novelty is more important to the present generation than form and function.

Architecture, however, has not died, she said. In fact, the current period of questioning may lead the field to "a greater range of richness," she added.

On a more local note, Huxtable said she had seen some of Richard Stirling's plans for the Fogg Museum's new wing, and that Stirling is "doing a brilliant job of compressing numerous and diverse functions into a small space."