Barbara Spellman

Calibration Trumps Confidence as a Basis for Witness Credibility

CO-AUTHORS Elizabeth R. Tenney, Robert J. MacCoun, and Reid Hastie
Psychological Science

UVA Law Faculty Affiliations

Barbara A. Spellman


In the courtroom and in laboratory studies, confident witnesses are viewed as more credible, and thus have more influence on judgments and verdicts, than unconfident witnesses. In two experiments (with college student subjects) we demonstrate that erroneous testimony may damage the credibility of a high-confidence witness more than a low-confidence one. We show that listeners rely on a source's calibration - whether the source's confidence is appropriate to the level of knowledge - rather than confidence when evaluating testimony.


Reid Hastie et al., Calibration Trumps Confidence as a Basis for Witness Credibility, 18 Psychological Science 46 (2007).

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