The rise of mass communication in the 1920s demonstrated the comprehensive in?uence of the emerging psychology at the time on social science. French group psychology, German psychoanalysis and Watson's behavioristic psychology had a profound impact on communication, despite their different perspectives. They injected the elements of the mass society, the irrational cognition of group psychology, and the scientifc measurement methods of individual psychology into the ?edgling communication studies through the main founders of American communication, such as Lippmann, Lasswell, Lazarsfeld, etc. As a result, the mass psychology paradigm of communication research formed. In the period of World War II and the Cold War, communication continued to strengthen the mass psychology paradigm because of the need of psychological warfare. The latter deprived the various possible development directions of communication and shaped it into knowledge tool for internal social control and external defense of the Cold War. Therefore, there has never been a real mass communication but only real mass psychology. After the end of the Cold War, faced with the great changes in the political and economic framework, the problems faced by the United States also changed fundamentally. The mainstream paradigm of communication lost its continuous resource support. However, due to habitus, communication scholars still insisted on using mass psychology to understand the communication phenomenon. Thus, the imagination of American communication studies was exhausted.