The most noticeable addition to music during this era stemmed from the Negro spirituals that were sung in previous centuries. These spirituals which were a racial characteristic would begin to evolve into a more formalized type of music, Jazz. This form of music showed deceptive simplicity and would continue to remain a large part of American culture into the present era. Jazz is played on the theory that an infinite amount of melodies could fit the chord progression of any composition.
Jazz is an improvisational skill by the performed and the instrumentalist.
The performed repeats the chord progression of a composition, while the instrumentalist imitates the black vocal styles and tonal effects. Thus, two formal patterns of improvisation were brought about. The second pattern has roots deep in African American folk music. It is in the blues form and has a fairly standard chord progression. Jazz music is idiosyncratic by nature where the performer creates the rhythm.