Health Risk Appraisal and Optimistic Bias

The judgments people make about health and safety hazards can influence their decisions and their behavior. Just as hazards are multidimensional, so are appraisals of these hazards. These appraisals often depart from the perceptions of experts, partially explaining why people fail to take recommended precautions. One reason for expert–layperson disagreements is the public's difficulty in understanding numerical presentations of probabilities and odds. Another reason is an optimistic bias about personal risk, a tendency to believe that one's own vulnerability is less than the vulnerability of one's peers. Depending on the context, underestimation of risk may be harmful or beneficial.