Testing encoding specificity and the diagnostic feature-detection theory of eyewitness identification, with implications for showups, lineups, and partially disguised perpetrators

Abstract

The diagnostic feature-detection theory (DFT) of eyewitness identification is based on facial information that is diagnostic versus non-diagnostic of suspect guilt. It primarily has been tested by discounting non-diagnostic information at retrieval, typically by surrounding a single suspect showup with good fillers to create a lineup. We tested additional DFT predictions by manipulating the presence of facial information (i.e., the exterior region of the face) at both encoding and retrieval with a large between-subjects factorial design (N = 19,414). In support of DFT and in replication of the literature, lineups yielded higher discriminability than showups. In support of encoding specificity, conditions that matched information between encoding and retrieval were generally superior to mismatch conditions. More importantly, we supported several DFT and encoding specificity predictions not previously tested, including that (a) adding non-diagnostic information will reduce discriminability for showups more so than lineups, and (b) removing diagnostic information will lower discriminability for both showups and lineups. These results have implications for police deciding whether to conduct a showup or a lineup, and when dealing with partially disguised perpetrators (e.g., wearing a hoodie).

One perpetrator, two perpetrators: The effect of multiple perpetrators on eyewitness identification

“…In line with current recommendations (Gronlund et al, 2014; National Research Council, 2014; Wixted & Mickes, 2012) and recent eyewitness ID research (Carlson et al, 2019a, 2019b; Carlson et al, 2021; Wooten et al, 2020), we used receiver operating characteristic (ROC) analysis to investigate how encoding one versus two targets impacts eyewitness accuracy. The application of ROC analysis to eyewitness data is an improvement over widely used probative value measures—such as the diagnosticity ratio (DR)—because while the DR confounds discriminability with response bias, ROC analysis separates these two parameters (Gronlund et al, 2014; Rotello & Chen, 2016).…”

Perpetrator pose reinstatement during a lineup test increases discrimination accuracy

“…Neurophysiological studies also indicate pose-sensitivity in cortical regions 12 . In the context of police lineups, overlapping cues at learning and test, such as the quantity of facial information available at encoding versus test (i.e., internal portion of faces versus full faces) 13 , clothing 14 , and disguises 15 boost discrimination accuracy. Context reinstatement 16 and alcohol state-dependent learning 17 effects have also been reported in the eyewitness literature.…”

Improving face identification of mask-wearing individuals

“…One of the most readily observable changes is the widespread usage of face coverings, which has serious implications for face recognition and eyewitness identification. Despite the extensive literature on both domains, few studies have examined the influence of face coverings on identification (Carlson et al, 2021 ; Davies & Flin, 1984 ; Freud et al, 2020 ; Mansour et al, 2012 ; Righi et al, 2012 ), and even fewer were designed to address this challenge (Manley et al, 2019 ). Consequently, there are currently no evidence-based recommendations for how to administer a lineup for crimes involving a masked perpetrator.…”

“…Face identification based on memory (i.e., recognition) and perception (i.e., face matching) is impaired by mask-wearing (Carlson et al, 2021 ; Carragher & Hancock, 2020 ; Davies & Flin, 1984 ; Mansour et al, 2012 ) or disguises in general (Noyes & Jenkins, 2019 ; Shapiro & Penrod, 1986 ). Researchers have generally treated masking-wearing as an estimator variable (Cutler et al, 1987a , 1987b ; Mansour et al, 2012 ; Shapiro & Penrod, 1986 ), because whether or not someone wears a mask when committing a crime is not under the control of the criminal justice system (Wells, 1978 ).…”