The Effect of Filler Selection Methods on Lineup Fairness and Eyewitness Identification

Document Type


Degree Name

Doctor of Philosophy (Ph.D)


Psychology and Special Education

Date of Award

Summer 2021


Eyewitness identification researchers consider procedures utilized by police as system variables, which is due to the criminal justice system being capable of controlling which procedures are recommended as optimal for gathering eyewitness evidence. Lineups are commonly used to facilitate an eyewitness identification decision pertaining to a suspect. The method with which a lineup is constructed is an important system variable to investigate, considering lineup composition has been shown to affect eyewitness identification performance. Fair lineups are recommended, and produce the best eyewitness identification accuracy (Wells, 1993; Wetmore et al., 2015, 2016). However, which method for creating fair lineups that best enhance eyewitness identification performance remains unclear. Filler selection methods may lead to differences in eyewitness ability to differentiate between innocent and guilty suspects, and are in need of further investigation, as some evidence has supported an advantage for matching fillers to the description of the suspect over matching them to the suspect’s appearance (e.g., Carlson et al., 2019; Wells, Rydell, & Seelau, 1993). In the current study, I investigated the effects of filler selection method on eyewitness identification, and I sought to determine whetherfiller selection methods produce differing estimates of lineup fairness. Participants took part in a multi-block face recognition paradigm consisting of multiple targets presented during encoding followed by various target-present and target-absent lineup tasks created using differing filler selection methods. Target-matched lineups were compared to four description-matched lineups differing in description quality: (a) a vague description using general characteristics, (b) with additional internal facial features, (c) with additional external facial features, or (d) with a mixture of both internal and external facial features. I hypothesized an increase in discriminability for description-matched compared to target-matched lineups regardless of the quality of description (Carlson et al., 2019; Wells et al., 1993; Wixted & Mickes, 2014), but I failed to find a difference between these two filler-selection methods. Matching fillers to internal and external features increased discriminability relative to matching fillers to no internal information. I also found that lineups with the best discriminability produced the lowest lineup fairness estimates. Further research is needed to determine the effect of filler-selection, feature type, and lineup fairness on eyewitness ID performance.


Curt A. Carlson

Subject Categories

Education | Educational Psychology