Abstract
Because real-world eyewitness memory performance has potentially life-changing consequences, researchers work to optimize lineup conditions to maximize the number of correct identifications while simultaneously minimizing the number of false identifications. A typical police lineup involves the simultaneous or sequential presentation of six photographs (one suspect and five similar fillers), and a witness either identifies one of the photographs (the suspect or a filler) as matching the perpetrator in memory or rejects the lineup completely. Sometimes, the police instead use a “showup” procedure in which a single photo of the suspect is shown without other lineup photographs present. Showups yield lower discriminability than lineups, but they maximize information about the suspect because every confidence statement applies specifically to the suspect (unlike in a lineup, where a filler might be identified with some degree of confidence). In an effort to have the best of both procedures, recent research suggests that a rate-them-all (RTA) lineup may improve upon the standard simultaneous lineup. In this RTA approach, witnesses watch a mock crime video then individually evaluate each lineup photograph by providing a confidence rating that the person is the criminal from a video. In terms of discriminability, we find that performance in the RTA lineup is diagnostically inferior to both the standard simultaneous lineup and the already-known-to-be diagnostically inferior showup. Theoretically, this result may indicate that each explicit recognition decision (one decision for both a standard simultaneous lineup and a showup but many decisions for the RTA procedure) introduces random error (noise), thereby lowering discriminability.