An explanation of the hard-easy effect in studies of realism of confidence in one's general knowledge

Recent ecological approaches to realism of confidence in general knowledge (Gigerenzer, Hoffrage & Kleinbolting, 1991; Juslin, in press) argue that people are well-calibrated to their natural environments. Both the overconfidence phenomenon and the hard-easy effect are explained as consequences of informal experimenter-guided selection of almanac items, selection that changes the validity of the cues used by the subjects for selection of answers to the items. The paper presents the ecological approach and reports an experiment showing that: (1) when the objects of judgement are selected randomly from a natural environment, people are well-calibrated; (2) when more and less difficult item samples are created by selecting items with more and less familiar contents, i.e. in a way that does not affect the validity of the cues, no hard-easy effect is observed, and people are well-calibrated both for hard and easy item samples. These results, predicted by the ecological approach, provide further support for the ecological approach to realism of confidence.