Automatic optimism: Biased use of base rate information for positive and negative events Academic Article uri icon


  • People generally judge that positive events will occur in their lives and negative events will not, even when both events have the same objective likelihood to occur. In four studies, we examined the possibility that this optimistic bias is the result of people's automatic affective reactions to future events. Studies 1 and 2 demonstrate, in two different contexts, that people are consistently optimistic in their predictions, despite identical base rates for positive and negative events. In Study 2, optimistic bias was not influenced by incentives for motivated reasoning or rewards for accuracy, suggesting that bias was the result of automatic processes. Studies 3 and 4 showed that optimistic bias was more pronounced when predictions were speeded and when participants made predictions after exposure to affectively valenced words. Together, these findings suggest that people optimistically interpret base rates and that this optimism is due to an effortless affective process. 2007 Elsevier Inc. All rights reserved.

published proceedings


author list (cited authors)

  • Lench, H. C., & Ditto, P. H.

citation count

  • 53

complete list of authors

  • Lench, Heather C||Ditto, Peter H

publication date

  • May 2008