Eyewitness metamemory predicts identification performance in biased and unbiased lineups

Distinguishing accurate from inaccurate identifications is a challenging issue in the criminal justice system, especially for biased police lineups. That is because biased lineups undermine the diagnostic value of accuracy postdictors such as confidence and decision time. Here, we aimed to test general and eyewitness-specific self-ratings of memory capacity as potential estimators of identification performance that are unaffected by lineup bias. Participants (N = 744) completed a metamemory assessment consisting of the Multifactorial Metamemory Questionnaire and the Eyewitness Metamemory Scale and took part in a standard eyewitness paradigm. Following the presentation of a mock-crime video, they viewed either biased or unbiased lineups. Self-ratings of discontentment with eyewitness memory ability were indicative of identification accuracy for both biased and unbiased lineups. Participants who scored low on eyewitness metamemory factors also displayed a stronger confidence-accuracy calibration than those who scored high. These results suggest a promising role for self-ratings of memory capacity in the evaluation of eyewitness identifications, while also advancing theory on self-assessments for different memory systems.