The study of health communication really emerged in the late 1950s and early 1960s with a focus on health promotion. In other words, the prominent question to emerge was: how can we use the media to encourage people to engage in positive health behaviors? There were two distinct theoretical developments that occurred during this time period: diffusion of innovations and the health belief model. The health belief model set the stage for research on fear appeals, such as the extended parallel process model. Research on health communication has also focused on models of the attitude-behavior relationship, such as the theory of reasoned action and its derivatives. This makes sense, because many health campaigns specifically focus on changing people’s attitudes as a way to decrease unhealthy behaviors or to increase healthy behaviors.