sage content. If one’s friends respond to an antismoking or a dental hygiene message with anger or derision, the context may be converted into one of resistance rather than careful processing and possible acceptance of the message content. Theories of media effects provide a framework for understanding how mass communication messages ultimately influence beliefs and behavior.

In this chapter, we first consider behavioral theories and their implementation. We then consider theories of communication and persuasion, and theories of media effects. Rather than summarizing and describing the various theories in each of these areas, our focus is on identifying the critical concepts in these theories and on their theoretical integration. Many good reviews of theories have been conducted (e.g., Glanz, Lewis, and Rimer, 1997), but far fewer attempts have been made to synthesize constructs and achieve integration among behavioral theories or between behavioral and communication theories. Finally, we consider the implications of these theories for developing health messages for diverse audiences. “Good” theories not only recognize the role of diversity, but, when implemented properly, are specific to both the behavior of interest and to the population involved.

This volume shows that health disparities may reflect variations in biological risk factors, differences in access to diagnostic or treatment facilities, or behavioral differences. These latter differences (in health behaviors) are amenable to change via communication interventions. In order to develop health communication messages to eliminate or reduce the behavioral differences, it is essential to understand factors influencing the performance (or nonperformance) of a given health behavior. There are many theories of behavioral prediction, including:

• Theory of Planned Behavior (e.g., Ajzen, 1985, 1991; Ajzen and Madden, 1986);