Antidotes for Anthrax Anecdotes: The Role of Rationality and Base-Rate Data in Assuaging Apprehension

Two experiments, conducted approximately 6 weeks apart, examined the conjoint effects of participant rationality, as assessed by the Rational- Experiential Inventory, and base-rate information on apprehension about a threat. Experiment 1 predicted and found that high-rationality individuals who first received context-expanding information about a relatively likely hazard (traffic deaths) manifested less apprehension in response to a subsequent news story about a less likely threat (anthrax death) than did highs who read only the anthrax-death story. It was further predicted and found that among low-rationality individuals this relationship was reversed. Experiment 1 was conducted when the anthrax threat was perceived to be quite serious. The interaction was not found in Experiment 2, after national attention to anthrax decreased. Findings are discussed in terms of how high- and low- rationality individuals process threat-related information and how they respond to changes in the perceived seriousness of threat.