Postdictive confidence (but not predictive confidence) predicts eyewitness memory accuracy

If testing conditions are uncontaminated, confidence at test reliably predicts eyewitness memory accuracy. Unfortunately, information about eyewitness postdictive confidence (at the time of the identification test) is frequently unavailable or not well documented. In cases where postdictive confidence is unavailable, a useful indicator of eyewitness accuracy might be an eyewitness’s predictive confidence made shortly after the event. How do the accuracy of predictive and postdictive confidence judgments compare; and do variables reported to affect memory (e.g. exposure duration, face race) affect the reliability of the confidence-accuracy relationship for predictive and postdictive judgments? In two experiments, we tested the accuracy of memory predictions (immediate and delayed judgments of learning [JOLs]) and postdictions (confidence) for same- and cross-race faces. Although delayed high JOLs were indicative of higher recognition memory accuracy than delayed low JOLs for both same- and cross-race faces, the accuracy of even high predictive JOLs was objectively low. Postdictive confidence was a far stronger indicator of memory accuracy than predictive JOLs; high postdictive confidence was indicative of high accuracy; and this was true for both same- and cross-race recognition memory. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s41235-018-0125-4) contains supplementary material, which is available to authorized users.