Getting ahead of illness: using metaphors to influence medical decision making.

BACKGROUND Metaphors influence judgments and decisions in nonmedical contexts. OBJECTIVE First, to investigate whether describing the flu metaphorically increases an individual's willingness and interest in getting a flu vaccination, and second, to explore possible mediators and moderators of the effect that metaphors might have on vaccination intentions. MATERIALS AND METHODS Three studies, each using a between-subjects manipulation in which the flu was described literally (as a virus) or metaphorically (as a beast, riot, army, or weed), were conducted. A total of 167 psychology undergraduates (study 1) and 300 and 301 online participants (studies 2 and 3, respectively) were included. Studies 1 through 3 examined vaccination behavioral intentions, absolute risk, comparative risk, perceived flu severity, and recent flu and flu vaccination experience. Studies 2 and 3 assessed vaccination e-mail reminder requests and global affect. Study 3 evaluated affective reactions, personal control, and understanding of the flu. RESULTS Describing the flu metaphorically increased individuals' willingness to get vaccinated (studies 1-3), while the impact of metaphors on requests to receive an e-mail reminder to get vaccinated was unclear (studies 2 and 3). These results were moderated by vaccination frequency in study 2, such that the effects were found among individuals who occasionally receive flu vaccinations but not among individuals who never or always receive flu vaccinations. Metaphor use did not significantly impact any of the hypothesized mediators: perceived absolute risk, comparative risk, flu severity, affect, personal control, or understanding of the flu. Limitations include convenience samples and measuring behavioral intentions but not actual vaccination behavior. CONCLUSIONS Describing the flu virus metaphorically in decision aids or information campaigns could be a simple, cost-effective way to increase vaccinations against the flu.