Joan Acocella: The New Dance Group, at the 92nd Street Y: The New Yorker For a number of reasons - notably, Fascism and Communism - much of the best art of the nineteen-thirties was political art. This was especially true in American modern dance, because it was young (new arts are more sensitive to new trends) and because the field all but defined itself, from the start, as anti-establishment. The best example is the New Dance Group, founded in New York in 1932 and devoted to creating dances about the plight of the proletariat. The N.D.G. charged ten cents a class, which covered an hour of studio work, an hour of improvisation on a political subject, and an hour of discussion of social issues - a considerable bargain. Some dances produced by the group were no doubt thudding agitprop. The photographs show earnest young women marching around with flags. But in the pieces I've seen, the genre's simplicities are often joined with a bracing energy. On Feb. 1, at noon, the 92nd Street Y will give a concert of remounted N.D.G. dances, including works by Anna Sokolow, Sophie Maslow, Jane Dudley, Charles Weidman, and others. The program will include a panel and an archival film, and it's free. ♦