Suspect filler similarity in eyewitness lineups: A literature review and a novel methodology.

Abstract

Eyewitness lineups typically contain a suspect (guilty or innocent) and fillers (known innocents). The degree to which fillers should resemble the suspect is a complex issue that has yet to be resolved. Previously, researchers have voiced concern that eyewitnesses would be unable to identify their target from a lineup containing highly similar fillers; however, our literature review suggests highly similar fillers have only rarely been shown to have this effect. To further examine the effect of highly similar fillers on lineup responses, we used morphing software to create fillers of moderately high and very high similarity to the suspect. When the culprit was in the lineup, a higher correct identification rate was observed in moderately high similarity lineups than in very high similarity lineups. When the culprit was absent, similarity did not yield a significant effect on innocent suspect misidentification rates. However, the correct rejection rate in the moderately high similarity lineup was 20% higher than in the very high similarity lineup. When choosing rates were controlled by calculating identification probabilities for only those who made a selection from the lineup, culprit identification rates as well as innocent suspect misidentification rates were significantly higher in the moderately high similarity lineup than in the very high similarity lineup. Thus, very high similarity fillers yielded costs and benefits. Although our research suggests that selecting the most similar fillers available may adversely affect correct identification rates, we recommend additional research using fillers obtained from police databases to corroborate our findings.

Metacognitive Control and Lineup Instructions: Asking eyewitnesses to recollect reduces false identification

“…Further, Malmberg and Xu (2007) found that when associative recognition tests feature both high-and low-similarity fillers, participants made less use of recollection than when target-filler similarity was uniformly high. Typically, target-filler similarity is not uniform across lineup members and reviews of lineup similarity effects (e.g., Fitzgerald et al, 2015) and empirical tests of the 'dud effect' (Charman, Wells, & Joy, 2011) demonstrate patterns like those found in associative recognition. That is, when simultaneous lineups include some fillers with relatively lower similarity to the offender, eyewitnesses mistakenly anticipate that distinguishing a guilty suspect will be relatively easy and are more likely to mistakenly identify an innocent suspect who closely resembles the offender than when targetfiller similarity is uniformly high.…”

Examining Lineup Identification as a Function of Foil Similarity and Lineup Procedure

“…Additionally, relative risk ratios were calculated to compare the diagnosticity of the lineup procedures to determine if they were significantly different from each other. Fitzgerald and Price (2015) suggest that the relative risk ratios are beneficial, as they have known sampling distributions and established methods of computing confidence intervals. The risk ratio was calculated in a similar way to the DR whereby the number of suspect identifications was divided by the total number of identifications (divided by 6, as there was no designated innocent suspect).…”

“…One major challenge that has appeared within the foil similarity literature is that researchers seem to be having difficulty conceptualizing what constitutes as high, moderate, and low similarity. It is possible that this challenge is occurring because researchers are trying to take a concept that is measured on a continuum and attempting to break it down into distinct categories (i.e., low vs. high; Fitzgerald et al, 2015). For example, in the current study and in Fitzgerald et al (2015) the photograph ratings used for the construction of the high similarity lineups had mean similarity ratings around the mid-point of the similarity scale (current study: M = 4.49 on a scale of 1 to 10).…”

“…It is possible that this challenge is occurring because researchers are trying to take a concept that is measured on a continuum and attempting to break it down into distinct categories (i.e., low vs. high; Fitzgerald et al, 2015). For example, in the current study and in Fitzgerald et al (2015) the photograph ratings used for the construction of the high similarity lineups had mean similarity ratings around the mid-point of the similarity scale (current study: M = 4.49 on a scale of 1 to 10). So while the high similarity lineup was indeed higher similarity in contrast to the low similarity lineup that was used (current study: M = 2.03), in the broader scope of this type of research it may not have been as highly similar as is necessary to observe any substantial effects.…”

“…While research regarding eyewitness identification has been of great interest for many years, much of the past 30 years has focused on differences across lineup procedures (e.g., Pozzulo, Reed, Pettalia, & Dempsey, 2015;Wells, Steblay, Dysart, 2015). However, one aspect of the lineup procedure literature that has been largely understudied relates to lineup construction, more specifically, foil similarity (Fitzgerald, Oriet, & Price, 2015).…”