This study explores the effect of negative exemplars on two-sided message recall and risk perception, as mediated by negative affect. In an experiment, participants were randomly assigned to an article presenting conflicting risk arguments about vaccination that included a photograph exemplifying one argument side (receiving a vaccine is risky), a photograph exemplifying the other argument side (not receiving a vaccine is risky), or no photograph (control condition). Exemplifying the risks associated with vaccination influenced uneven recall and risk perception. Negative affect, rather than perceived argument strength, mediated these effects and was a stronger predictor of risk perception than risk argument recall, lending support to the affect heuristic. However, exemplifying the risk of not vaccinating produced null effects on affect, risk perception, and recall, despite using the same photograph. A follow-up study suggests that motivated reasoning played a role in this null finding, providing direction for future research.