Eyewitness confidence : the relation between accuracy and confidence in episodic memory

Abstract

Many decisions in the legal system are based on eyewitness evidence. It seems to be a matter of common sense that the level of confidence expressed by a witness can be used as a diagnostic tool to discriminate between accurate and inaccurate memories. Contrary to this general belief, the bulk of empirical evidence collected in laboratory and field experiments over the past 25 years indicates that the relationship between confidence and accuracy is far from perfect. The central focus of this dissertation is on the accuracy of eyewitness memory, and especially on the relationship between accuracy and confidence (i.e., the subjective judgment of accuracy). To enhance the ecological validity of the laboratory studies, we used a method that allowed us to determine accuracy and confidence scores for the recall of details of complex naturalistic events. The first three chapters are experiments from the laboratory testing the effect of repeated retrieval, retention interval and repeated misleading questioning. The fourth chapter is a case study in which real live witnesses of a robbery on a supermarket were interviewed. Our findings show a clear and consistent relationship between confidence judgements and the actual accuracy of memories. With some caution, confidence may be used as a partial indicator of accuracy, especially during the early stages of an investigation. Unfortunately, however, there always remain incorrect items that are given the maximum confidence score. That is the reason why no single witness statement can be accepted as certainly correct, based on confidence alone.</p