Reducing people's judgment bias about their level of knowledge

Two experiments were conducted to replicate and extend previous findings wh ich indicated that judgment bias about the extent of one's own knowledge ca n be decreased by a de-biasing technique called counterfactual reasoning, t hat is, having people consider why their answers to questions may be wrong. The results of the two experiments confirm the effectiveness of this techn ique to decrease bias, by statistically controlling for important variables . The results extend previous findings about its effectiveness, by showing that counterfactual reasoning (a) reduced bias on knowledge questions about a specific subject area and (b) reduced bias on both hard and easy test qu estions. In addition, the two experiments establish that bias and test perf ormance are inversely related, and a theoretical connection between this re lationship and the ubiquitous hard/easy effect in bias research is offered. The results are discussed in terms of decision-making processes and the po tentially detrimental effects of bias on test performance and learning in g eneral.