The application of multiple lineups in a field study

Abstract

The usefulness of multiple lineups was tested in a field experiment with nine different targets. Six hundred and forty-eight passers-by were asked for directions in the pedestrian zone of a university town. Subsequently, they were approached by a different person and asked to identify the target from portrait, body, and profile lineups. Additionally, participants were asked to identify a shopping bag that the target had carried. Two of the lineups were target-present, and two target-absent. Diagnosticity ratios (DRs) were computed for target/suspect choices, lineup rejections and foil choices. Compared to foil choices and rejections, target/suspect choices were most diagnostic of guilt. Here, the combination of lineups was superior over individual lineups. Lineup rejections showed some capability of establishing innocence, but with lower DRs than target/suspect choices. Here, combinations did not increase diagnosticity. The diagnosticity of multiple foil choices was acceptable for portrait face lineups but limited for all other lineups or combinations.