Patients who are unrealistically optimistic about their personal health risks are more likely to take preventive action when confronted with news that is worse than expected, while unrealistic pessimists are less likely to change their behavior after receiving feedback that is better than expected, according to researchers at the University of California, Riverside and Grand Valley State University in Allendale, Mich.

This poses a serious dilemma for health care professionals, said study authors Kate Sweeny, assistant professor of psychology at UC Riverside, and co-author Amanda Dillard, assistant professor of psychology at Grand Valley State University: Should they withhold accurate risk information from unrealistic pessimists to avoid undermining their perceptions of the severity of their potential consequences and ultimately their motivation for preventive behavior?

"The question reveals a tension between the goals of health-behavior promotion and informed patient decision-making that has plagued researchers in several health domains, most notably with regard to women's often overly pessimistic perceptions of their breast cancer risk," Sweeny and Dillard wrote in "The Effects of Expectation Disconfirmation on Appraisal, Affect, and Behavioral Intentions," published this month in the online edition of Risk Analysis: An International Journal. The journal is an official publication of the Society for Risk Analysis, a multidisciplinary, interdisciplinary, scholarly, international society based in McLean, Va.

"Our findings cannot resolve this tension, but rather point to the need for further consideration of the potential consequences of risk communication," the researchers said.

Sweeny and Dillard are the first to demonstrate that how an individual reacts and responds to objective risk feedback may depend on initial expectations prior to the feedback.

The psychologists conducted a series of experiments in which participants were told they would be tested for exposure to toxins found in everyday products. The researchers found that people who received risk feedback that was worse than expected expressed stronger intentions to prevent the threat in the future than did people who received risk feedback that was better than expected. All study participants received the same health feedback; only the expectations of the participants differed.

"Our findings add critical pieces to the previously incomplete picture of the consequences of expectation disconfirmation," they wrote. "Ours is the first experimental investigation of the relationship between expectation disconfirmation and behavioral intentions in the context of personal risk perceptions, and the first study to examine the process by which intentions might rise or fall in response to unexpected risk feedback."

Contrary to findings in other recent studies, Sweeny and Dillard determined that when people are faced with objective feedback that differs from their perceptions of health risks, they may adapt their behavior to fit the new risk information.

"In our studies, participants who learned that their risk was higher than they expected ... formed relative strong intentions to take preventive action," they said. They also found that people who learned that their risk was lower than expected felt relatively good in the face of feedback and formed relatively weak intentions to take preventive action. All of the study participants received the same health risk feedback.

"Our findings point to an important tradeoff people face when managing their expectations as they await feedback: maintaining optimism leaves people open to disappointment, but bracing for the worst may undermine future motivation to improve," they said. "... It seems that people find the emotional consequences of being caught off-guard more compelling than the potential for elation to undermine their motivation to change their behavior in response to feedback."