Motivation Influences the Underestimation of Cumulative Risk

Past research has shown that people typically underestimate the cumulative risk of events. This effect has mainly been interpreted as resulting from the use of cognitive heuristics and judgment strategies, such as availability or anchoring and adjustment. The authors suggest that motivational processes can be an additional force in the generation of cumulative risk estimates. Using an experimental design, Study 1 shows that people underestimate the cumulative risk of infection with sexually transmitted diseases of appealing prospective sexual partners by using risk-irrelevant information for their judgment. Using a correlational design, Study 2 demonstrates that people underestimate the cumulative risk of being infected with a sexually transmitted disease and that commitment to the present partner is directly related to a low cumulative risk estimate as well as indirectly through its effect on the perceived risk of the present partner. Together, the two studies demonstrate that motivation influences the underestimation of cumulative risk.