Background: Extended Parallel Process Model, behavioral model, and empathetic approach proposed different theoretical assumptions in explaining why people take vaccines. Yet no single reviewed empirical study tried to compare their theoretical effectiveness in motivating people to join the vaccination campaign. This study therefore tried to fill this gap via examining the persuasiveness of different promotion materials to the participants in a hypothetical vaccination campaign, while controlling a number of personal factors and writing styles of the materials.
Methods: A total of 216 adult participants were recruited for this questionnaire-based study. All participants were firstly introduced to a hypothetical scenario and then randomly assigned into 4 different groups. They were asked to read corresponding promotion materials before deciding their likeness to receive a vaccination.
Results: All promotion materials were effective in enhancing the likeliness of taking the vaccination, compared with the control condition. After controlling participants' age, their vaccination records, and health efficacy, participants were more likely to join the vaccination campaign after reading the promotion materials related with efficacies and caring for others, than reading the materials about positive reinforcements, regardless of the writing styles.
Conclusion: These exploratory findings provide empirical evidence in further understanding the ways of delivering the important messages in public communication. The current research suggests that the feasibility of the effective resources and empathetic gestures to the needy should be prominently emphasized in the promotion of vaccination campaigns, whereas participants might feel a diminution of their prosocial behaviors when money rewards were associated. Limitation of the research design is also discussed.
Keywords: Extended Parallel Process Model; empathy; motivation; reinforcement; vaccination.