Biased lineups and additional repetitions exacerbate the repeated-suspect effect

When an eyewitness is presented with multiple lineups, each containing the same suspect but entirely new fillers, this increases the risk that an eyewitness will identify the suspect-whether that suspect is innocent or guilty (called the repeated-suspect effect). There are several mechanisms that can lead to repeated-suspect effects, some based in memory processes and others based in social influence processes. Across two in-person experiments, we examined conditions that might exacerbate the repeated-suspect effect. In Experiment 1 (N = 316, collected in 2019), we showed that a previous lineup that is biased toward the innocent suspect exacerbates the repeated-suspect effect but found no evidence that participants' memory for the true culprit was affected. In Experiment 2 (N = 303, collected in 2020), additional intervening lineups increased the risk to innocent suspects. Experiment 2 also highlighted the role of social influence in eyewitness errors. We found that the physical presence of the experimenter during the task influenced their choice to identify the repeated person, especially after a biased lineup. Thus, we show evidence for the role of memory and social influence mechanisms in repeated-suspect effects as well as dramatic increases in the risk to innocent suspects when intervening lineup procedures make the suspect more salient to the viewer. (PsycInfo Database Record (c) 2026 APA, all rights reserved).