ABSTRACT
This chapter illustrates that even the smartest people can be subject to irrational conclusions, by noting how cognitive psychologists themselves have ignored a valid statistical relationship when no story justifies it. Specifically, it analyzes the irrational belief, first proposed and subsequently endorsed by many cognitive psychologists themselves, termed the social false-consensus effect. According to this effect, people suffer from an egoistic bias to exaggerate the degree to which others are like them. In fact, sometimes people do suffer from such a bias, but the criterion for determining its existence is an irrational one. Nevertheless, this criterion was proposed and accepted for ten years by social and behavioral decision-making psychologists. The analysis of sample unbiased estimate of overall population values indicates the deficiency of the specification that led to a belief in the falsity of consensus reasoning. Unbiased estimates do vary across samples. Each estimate that is constructed has as its expectation the true value it estimates.
