How Lineup Type and Memory Quality Affect Decision Accuracy and the Confidence-Accuracy Relationship

Abstract

The purpose of the current study was to gain a more informed understanding of the estimator and systematic variables which may predict decision accuracy in lineups. An estimated 75% of wrongfully convicted suspects who were later exonerated by DNA evidence through the Innocence project (The Innocence Project, 2009), were victims of incorrect identification errors. A mixed design study was conducted on 98 participants, which manipulated lineup type (simultaneous and sequential) and memory quality (poor, moderate and good). The participants viewed a video-taped crime on a computer screen and were later asked to view two lineups: one contained a guilty suspect and one did not. Our findings allow us to conclude that neither lineup type nor memory quality had a significant effect on accuracy. Lineup type and memory quality did not have a significant effect on confidence when the target was not present. Analysis of the confidence-accuracy calibration shows that confidence informed accuracy in both target-absent (TA)and target-present (TP) conditions.