Eyewitness Identification: A Systematic Investigation of Lineup Composition and Fairness

The authors of this study sought to replicate the advantage of fair photo arrays over biased photo arrays and showups as well as to test Diagnostic Feature Detection (DFD) theory with photo arrays of different levels of fairness (based on filler similarity). The major objective of this project was to investigate photo array composition in order to improve eyewitness identification (ID) procedures. The authors investigated these ID procedures while manipulating other important eyewitness variables. Photo array composition involves the fillers, or known-innocent individuals that police add to a photo array so that the suspect does not stand out. An unbiased, or fair, photo array contains fillers that match the description of the perpetrator provided by one or more eyewitnesses. In contrast, in a biased photo array the suspect stands out from the fillers. Another popular ID procedure used by police is the showup, when the suspect is presented without any fillers. This project involved all three of these ID procedures. Several issues were unclear in the eyewitness ID literature regarding the ID procedure and how it interacts with other eyewitness variables, and this project addressed many of them.