Designing messages to reduce meat consumption: a test of the extended parallel process model

The purpose of this study was to examine the utility of the Extended Parallel Process Model (EPPM) in guiding message design for a new health context, reducing meat consumption. The experiment was a posttest only design with a comparison and a control group. Message design was informed by the EPPM and contained threat and efficacy components. Participants (Americans ages 25-44 who eat meat approximately once a day) were randomly assigned to view a high threat/ high efficacy video, a high threat/ low efficacy video, or to be in a control group. Dependent variables were danger control outcomes (i.e., attitudes, intentions, and behavior) and fear control outcomes (i.e., perceived manipulative intent, message derogation, and defensive avoidance). Outcomes were assessed at an immediate posttest (Time 1) and at a one-week follow up (Time 2). There were 373 participants at Time 1 and 153 participants at Time 2. The data did not fully fit either the EPPM or the additive model; both videos were equally persuasive and resulted in greater message acceptance (attitude change, behavioral intention, and behavior) than the control group. Because the high threat/ low efficacy group was more persuasive than the control group, the data more closely fit the additive model. Fear control outcomes did not differ between the two video groups. Overall, the study demonstrated the effectiveness of using the EPPM to guide video message design in a new health context, reducing meat consumption. The results supported the EPPM prediction that a high-threat high-efficacy message would result in message acceptance, but support was not found for the necessity of an efficacy component for message acceptance. These findings can be used to guide new or existing health campaigns that seek to improve public health outcomes, including reducing the incidence of heart disease, cancer, diabetes, and obesity.