Perhaps the most critical determinant of whether a person does or does not perform a given behavior is the person’s beliefs about performing that behavior. Thus, behavioral theory, when properly applied, allows one to identify the beliefs that should be changed or reinforced to influence a given behavior change in a given population. Changing a person’s beliefs can be a precursor to changing a person’s behavior. Thus, behavior change can be said to be mediated by belief change. By recognizing that the critical beliefs in one population may be different from those in another population, behavioral theory helps in understanding the importance of diversity in developing effective health communications. However, knowing which beliefs to address does not tell us how to go about designing messages or interventions that can effectively reinforce or change those beliefs. Theories of communication and persuasion guide the selection of communication sources and channels and the preparation of the content of messages. For example, data about women’s beliefs regarding the value of mammography are important in creating interventions to enhance mammography use. However, finding out that many women in a given population do not believe that getting a mammogram will lead to early detection of breast cancer does not reveal how to design messages to convince them otherwise, or how to achieve social and environmental changes to influence this belief and therefore influence behavior change. By recognizing that different sources, channels, and message executions may be necessary for different populations, communication theories also point to the importance of considering diversity in developing effective health communication interventions.
We also recognize that communication interventions influence beliefs (and behavior) in different ways. Sometimes people exposed to a message learn the information that it contains, and this knowledge has a “direct” effect on their beliefs. But the context in which one receives the message also may influence how the message is received. For example, if a person is exposed to a message in the company of friends, their reactions to the message may strongly influence whether the person learns or accepts the mes-