From chance to choice: the use of a verbal analogy in the communication of risk

In risk communication to patients, Medical Doctors frequently use analogies attempting to enhance the otherwise poor comprehension of small probabilities by laypeople. Two experiments examined the effects of the verbal analogy (asking patients to figure out the probability of an outcome by imagining the chance to draw a winning ball from a jar) on individuals' probability perception by means of seven-point Likert scales. Study 1 showed that the employment of the verbal analogy reduced the perceived likelihood of the hypothetical event under judgment both in the positive (winning a 1 million Euro lottery) and in the negative domain (contracting malaria travelling to Africa). In Study 2, two possible versions of the verbal analogy (forced vs. weak) were tested on the perceived risk of contracting hepatitis A travelling to Africa. Results indicated that individuals' risk perception was decreased by the analogy only in the forced condition. The authors discuss possible explanations for this effect.