Skip to content

The single lineup paradigm: a new way to manipulate target presence in eyewitness identification experiments

Research output: Contribution to journalArticle

The suspect in eyewitness lineups may be guilty or innocent. These possibilities are traditionally simulated in eyewitness identification studies using a dual-lineup paradigm: all witnesses observe the same perpetrator and then receive one of two lineups. In this paradigm, the suspect’s guilt is manipulated by including the perpetrator in one lineup and an innocent suspect in the other. The lineup is then filled with people matched to either the suspect (resulting in different fillers in perpetrator-present and perpetrator-absent lineups) or to the perpetrator (resulting in the same fillers in each lineup). An inescapable feature of the dual-lineup paradigm is that the perpetrator-present and perpetrator-absent lineups differ not only in the suspect’s guilt, but also in their composition. Here, we describe a single-lineup paradigm: subjects observe one of two perpetrators and then receive the same lineup containing one of the perpetrators. This alternative paradigm allows manipulation of the suspect’s guilt without changing the lineup’s composition. In three experiments, we applied the single-lineup paradigm to explore suspect-filler similarity and consistently found that increasing similarity reduced perpetrator identifications but did little to prevent innocent suspect misidentifications. Conversely, when fillers were matched to the perpetrator using a dual-lineup paradigm, increasing similarity reduced identification of perpetrators and innocent suspects. This finding suggests that the effect of filler similarity may depend on the person to whom the fillers are matched. We suggest that the single-lineup paradigm is a more ecologically-valid and better-controlled approach to creating suspect-matched lineups in laboratory investigations of eyewitness memory than existing procedures.
Original languageEnglish
Number of pages12
JournalLaw and Human Behavior
Issue number1
StatePublished - 1 Feb 2018


  • Oriet Fitz LHB postprint

    Rights statement: © American Psychological Association, 2017. This paper is not the copy of record and may not exactly replicate the authoritative document published in the APA journal. Please do not copy or cite without author's permission. The final article is available, upon publication, at doi: 10.1037/lhb0000272.

    Accepted author manuscript (Post-print), 377 KB, PDF-document

Related information

Relations Get citation (various referencing formats)

ID: 8077660