The alternative-outcomes effect.

Distributions of possible scenario outcomes were manipulated without changing the probabilities of focal outcomes (e.g., you hold 3 raffle tickets and 7 other people each hold 1 vs. you hold 3 and another person holds 7 ). Participants' probability estimates confirmed that beliefs about the objective likelihood of the focal outcomes were largely unaffected by the manipulations. As expected, however, nonnumeric certainty estimates (Studies 1-3), feelings of concern (Study 4), and choice behaviors (Study 5) revealed that the manipulations did affect subjective certainty. The consistent direction of this alternative-outcomes effect and findings from Study 6 suggest that comparisons between the focal outcome and the strongest alternative have an important influence on subjective certainty. A potential function for these comparison processes is described, and their similarities with social comparison and social judgment processes are discussed.