A Disconfirmation Bias in the Evaluation of Arguments

Two experiments provided evidence for a disconfirmation bias in argument evaluation such that arguments incompatible with prior beliefs are scrutinized longer, subjected to more extensive refutational analyses, and consequently are judged to be weaker than arguments compatible with prior beliefs. The idea that people are unable to evaluate evidence independently of prior beliefs has been documented elsewhere, including in the classic study by C. G. Lord, L. Ross, and M. R. Lepper (1979) . The present findings contribute to this literature by specifying the processes by which prior beliefs affect the evaluation of evidence. The authors compare the disconfirmation model to several other models of how prior beliefs influence current judgments and present data that provide support for the disconfirmation model. Results indicate that whether a person's prior belief is accompanied by emotional conviction affects the magnitude and form of the disconfirmation bias.