Choosing lineup order vs knowing which lineup corresponds to which suspect: accuracy implications in multiple perpetrator identification

Abstract

Although many crimes involve multiple perpetrators, most eyewitness studies examine identification accuracy within the context of a single perpetrator. Prior research has indicated that stronger memory traces and lower cognitive load result in more accurate perpetrator identifications. In this study, 180 participants were shown a video of a simulated theft that involved two perpetrators. Afterwards, participants were randomly shown two lineups, each with a six-person simultaneous lineup. In one group (n = 60), the participant selected which lineup to view first; in the other groups, the administrator selected which lineup to view first. When the administrator chose the viewing order, half of the participants (n = 60) were aware of which lineup corresponded to which perpetrator and half (n = 60) were not. The participants who selected which lineup to view first correctly rejected target-absent lineups more often (65%) than those who did not know which lineup corresponded to which perpetrator (45%). There were no differences between the participants who selected which lineup to view first and those who could not choose the order but were aware which lineup corresponded to which perpetrator. In conclusion, being aware of which lineup corresponds to which perpetrator seems to be an important factor associated with eyewitnesses’ cognitive load.

Keywords

• eyewitness identification
• multiple perpetrators
• simultaneous lineups
• memory trace strength
• cognitive load.