Two theoretical orientations to cultural production are presented: the mass society and group action theories. It is argued that the two theories provide alternative, but not mutually exclusive, explanations for changes in cultural content and that the case of stylistic change in jazz between 1920 and 1940 presents an appropriate empirical test. Examining data on black jazz, its musicians and audiences in Detroit, it is found that a group action explanation has more power than a mass society explanation. Only one of the three stylistic changes isolated in a musicological analysis is causally related to the integration of jazz into the system of popular music production, whereas the other two changes are best accounted for by the purposive action of musicians as a group. Implications are drawn for the sociology of jazz as well as the study of cultural production.