DECISION MAKING BIASES IN JUDGMENTS ABOUT VASCULAR RISK FACTORS

 

Purpose: We investigate effects of psychological biases (i.e., overconfidence, framing and anchoring) on health-related judgments to test if biases can be integrated into the promotion of health-protective behaviors, specifically for lowering vascular risk factors.

Methods: To measure, if and how decisions on vascular risks are affected by the biases, we used self-administered questionnaires for data collection. Four different versions of the questionnaires were randomly given out to subjects. Manipulations were balanced between versions. We additionally asked for self-reports on the already performed health behavior, smoking status, as well as body weight. The questionnaire was completed by 187 healthy adults (86 women, 96 men, 5 missing values) with a mean age of 24.6 years (SD_age = 4.59).

Results: First, we found a general effect of overconfidence. On average, individual risks for diabetes, heart attack, and stroke were estimated to be significantly lower than that of a person with the same age, gender, and level of education. Similarly, the own life expectancy was estimated as “above average”. Second, as suggested by prospect theory, we found significant effects of framing. Subjects judged the intention to lose weight with different importance, when this information was presented in relation to people being thicker or thinner than themselves. If informed that 65% of the population weighed less, subjects were more concerned about controlling their weight than if informed that 35% of the population weigh more. Third, hypertension prevalence was estimated higher after presentation of a high than a low irrelevant anchor (Figure 1). Fourth, subjects from the high anchor group perceived blood pressure monitoring as less beneficial.    

Conclusions: We showed that judgments and behavioral motivation related to vascular risk factors are psychologically biased. In our study individuals are (i) overconfident about their vascular risks, (ii) easily biased in estimation of risk factors frequencies and (iii) lose concern for vascular risk factors if these are perceived to be frequent through the setting of different anchors. Beside a deeper understanding of why people often behave problematically in health related decision making our findings show that different contents in communication instruments can influence patients' perception and decision making in the field of vascular risks. We suggest that health-care providers should take into account the existence and relevance of those biases when conceptualizing communication instruments.