Passage: It was only after World War II, however, that the U.S. became the focal point of new artistic movements. The 1950s and 1960s saw the emergence of Abstract Expressionism, Color field painting, Conceptual artists of Art & Language, Pop art, Op art, Hard-edge painting, Minimal art, Lyrical Abstraction, Fluxus, Happening, Video art, Postminimalism, Photorealism and various other movements. In the late 1960s and the 1970s, Land art, Performance art, Conceptual art, and other new art forms had attracted the attention of curators and critics, at the expense of more traditional media. Larger installations and performances became widespread.

Question: What decades saw an increase in type of art?
1950s and 1960s