The repeated-suspect effect: What is the effect of repeated identification attempts on eyewitness accuracy and the original memory for the culprit?

Police routinely give eyewitnesses multiple opportunities to identify the same suspect, and numerous exoneration cases demonstrate that this practice can contribute to wrongful convictions. Empirical research addressing this practice shows it can lead to the repeated-suspect effect, which is a significant increase in suspect identifications after the same suspect has been presented in a previous showup or lineup (Steblay & Dysart, 2016). Procedures that tend to increase the chance of innocent suspect identifications are considered suggestive and produce unreliable eyewitness decisions. Thus, the use of multiple identification opportunities is considered suggestive and are discouraged by researchers (Wells et al., 2020). Despite this, eyewitness testimony obtained using suggestive procedures is frequently used at trial anyway because it is still admissible in court if other criteria are met indicating the identification was “nevertheless reliable” (Manson v. Brathwaite, 1977; Wells & Quinlivan, 2009). This dissertation builds on past research in this area by examining the effect of more the one intervening lineup and biased intervening lineups containing the same innocent suspect in two experiments, and how these different intervening lineup manipulations impact identification outcomes, confidence, and mechanism-related questions. Participants in both experiments watched a crime video, completed an intervening task phase, then evaluated a final, fair lineup. For Experiment 1, the intervening tasks were a fair lineup, a biased lineup, or a reading comprehension control task, and the final lineup contained either an innocent suspect, repeated from the intervening lineup, or the true culprit embedded among five fillers. For both studies, a repeated-suspect effect occurred such that a fair intervening lineup containing the innocent suspect resulted in more misidentifications of that same innocent suspect in the final lineup, consistent with past research. Furthermore, when