Illusion of confirmation from exposure to another's hypothesis

We examine the influence of exposure to an advisor's hypothesis, in the form of a point estimate of an uncertain quantity, on subsequent point estimates and confidence judgments made by advisees. In three experiments, a group of unexposed advisees produced their own estimates before being presented with that of the advisor, while a group of exposed advisees were presented with the advisor's estimate before making their own. Not surprisingly, exposed advisees deliberately incorporated the information conveyed by the advisor's estimate in producing their own estimates. But the exposure manipulation also had a contaminating influence that shifted what the advisees viewed as their own, independent estimates toward those of the advisor. Seemingly unaware of this influence, exposed advisees were subject to an illusion of confirmation in which they expressed greater confidence in the accuracy of the advisor's estimate than did unexposed advisees. Copyright © 2006 John Wiley & Sons, Ltd.