Building comprehension to enhance vaccination intentions: Evidence from the United States and Italy

Building on Cognitive Load Theory and the Elaboration Likelihood Model of Persuasion this study attempts to deepen our understanding of how health information campaigns related to vaccination work. We predict that including statistical information in health information campaigns will serve as a distraction that suppresses comprehension that renders the campaign less effective at persuading the public to vaccinate. Results from a survey experiment conducted on samples of US (n = 605) and Italian parents (n = 505) show support for the hypothesized relationship depends upon the form of comprehension (comprehension of how vaccines work versus comprehension of potential adverse effects of vaccinating). Specifically, both US and Italian parents show including statistical information reduces comprehension of how vaccines work, in turn reducing parents’ intentions to vaccinate themselves and their children. We find no support for the hypothesized mechanism when comprehension of potential adverse effects of vaccinating acts as the process variable.