Fair Forensic-Object Lineups Are Superior to Forensic-Object Showups

Abstract

When presenting a suspect to a witness for an identification attempt, fair lineups are superior to one-person showups. Relative to showups, fair lineups decrease innocent-suspect identifications to a greater extent than culprit identifications ( Steblay et al., 2003 ). We examined whether the lineup advantage extends from facial identification to forensic-object identification. Participants (N = 1906) watched a short video of a car theft and then completed two culprit-present or culprit-absent showups or lineups. Participants first attempted to identify the culprit from the video and then attempted to identify the vehicle from the video. Forensic-object lineups were superior to forensic-object showups to the extent that the cost of an innocent-suspect identification exceeded the cost of a missed culprit identification or to the extent that the base rate of culprit presence was low. Importantly, we are referring to actual costs and base rates in the real world rather than to methods of manipulating witness decision criteria (see Clark, 2012 for a similar approach). Finally, confidence discriminated between accurate and inaccurate suspect identifications for forensic-object lineups, but not for forensic-object showups.