Spurious consensus and opinion revision: why might people be more confident in their less accurate judgments?

In the interest of improving their decision making, individuals revise their opinions on the basis of samples of opinions obtained from others. However, such a revision process may lead decision makers to experience greater confidence in their less accurate judgments. The authors theorize that people tend to underestimate the informative value of independently drawn opinions, if these appear to conflict with one another, yet place some confidence even in the spurious consensus, which may arise when opinions are sampled interdependently. The experimental task involved people's revision of their opinions (caloric estimates of foods) on the basis of advice. The method of sampling the advisory opinions (independent or interdependent) was the main factor. The results reveal a dissociation between confidence and accuracy. A theoretical underlying mechanism is suggested whereby people attend to consensus (consistency) cues at the expense of information on interdependence. Implications for belief updating and for individual and group decisions are discussed.