A note on the failure to use negative information

Abstract

The failure of humans to search for and use negative information is investigated through repeated variations of Wason's card selection task, using four independent samples. The results confirm earlier findings that there is a strong ‘confirmation bias’. In line with our hypothesis, the results further suggest that there are two effects improving people's ability to search for and use negative information: concreteness-as-such and the activation of an applicable decision rule. It is also found that activation of an inadequate decision rule affects perception of the problem at hand. The results are inconclusive as regards whether or not the activation of an inadequate decision rule is detrimental to performance. It is argued that ‘confirmation bias’ can have both negative and positive economic and societal consequences.