Abstract
Post-decision confidence from witnesses who make a positive identification decision can serve as a valuable indicator of identification accuracy under certain conditions. International best-practice guidelines therefore recommend asking witnesses to indicate their confidence following a selection from a lineup. Three experiments that used Dutch identification protocols, however, reported no significant post-decision confidence-accuracy association. To examine this conflict between the international and the Dutch literature, we tested the strength of the post-decision confidence-accuracy relationship for lineups that followed Dutch protocol in two ways: we conducted an experiment and re-analyzed two experiments that implemented Dutch lineup protocols. As expected, the post-decision confidence-accuracy relationship was strong for positive identifications and weak for negative identification decisions in our experiment. The re-analysis of the pre-existing data showed a strong effect for positive identification decisions of participants up to the age of 40 years. For exploratory purposes, we also tested the confidence-accuracy relationship between lineup administrators' perception of witnesses' confidence and eyewitness identification accuracy. In our experiment, the relationship was strong for choosers and weak for nonchoosers. The re-analysis of pre-existing data showed no correlation between confidence and accuracy, unless we excluded adults over 40 of age. We recommend adapting the Dutch identification guidelines to reflect the current and previous findings on the post-decision confidence-accuracy relationship.