In the 1950s, as the cool style became popular in fashion, literature, and lifestyle around the West Coast of the United States, jazz began to change along with this cool style. The word cool here does not mean 'cool', but 'cynical'.

In the 1940s, jazz, not dance hall music, was popularized by musicians.[20] An experiment to improve the perfection of the music itself begins.

In the 1930s, the center of jazz moved to New York, and big band swing jazz, a style in which big bands played and danced happily (swing dance, Charleston dance, etc.), gained great popularity.