Culprit-absent Lineups Research Articles

Experimental validation of a multinomial processing tree model for analyzing eyewitness identification decisions

To improve police protocols for lineup procedures, it is helpful to understand the processes underlying eyewitness identification performance. The two-high threshold (2-HT) eyewitness identification model is a multinomial processing tree model that measures four latent cognitive processes on which eyewitness identification decisions are based: two detection-based processes (the detection of culprit presence and absence) and two non-detection-based processes (biased and guessing-based selection). The model takes into account the full 2 × 3 data structure of lineup procedures, that is, suspect identifications, filler identifications and rejections in both culprit-present and culprit-absent lineups. Here the model is introduced and the results of four large validation experiments are reported, one for each of the processes specified by the model. The validation experiments served to test whether the model’s parameters sensitively reflect manipulations of the processes they were designed to measure. The results show that manipulations of exposure duration of the culprit’s face at encoding, lineup fairness, pre-lineup instructions and ease of rejection of culprit-absent lineups were sensitively reflected in the parameters representing culprit-presence detection, biased suspect selection, guessing-based selection and culprit-absence detection, respectively. The results of the experiments thus validate the interpretations of the parameters of the 2-HT eyewitness identification model.

A validation of the two-high threshold eyewitness identification model by reanalyzing published data

The two-high threshold (2-HT) eyewitness identification model serves as a new measurement tool to measure the latent cognitive processes underlying eyewitness identification performance. By simultaneously taking into account correct culprit identifications, false innocent-suspect identifications, false filler identifications in culprit-present and culprit-absent lineups as well as correct and false lineup rejections, the model capitalizes on the full range of data categories that are observed when measuring eyewitness identification performance. Thereby, the model is able to shed light on detection-based and non-detection-based processes underlying eyewitness identification performance. Specifically, the model incorporates parameters for the detection of culprit presence and absence, biased selection of the suspect and guessing-based selection among the lineup members. Here, we provide evidence of the validity of each of the four model parameters by applying the model to eight published data sets. The data sets come from studies with experimental manipulations that target one of the underlying processes specified by the model. Manipulations of encoding difficulty, lineup fairness and pre-lineup instructions were sensitively reflected in the parameters reflecting culprit-presence detection, biased selection and guessing-based selection, respectively. Manipulations designed to facilitate the rejection of culprit-absent lineups affected the parameter for culprit-absence detection. The reanalyses of published results thus suggest that the parameters sensitively reflect the manipulations of the processes they were designed to measure, providing support of the validity of the 2-HT eyewitness identification model.

Evidence strength (insufficiently) affects police officers' decisions to place a suspect in a lineup.

We examined whether variations in the strength of the evidentiary connection between a suspect and the crime under investigation affected officers' decisions to place suspects into an identification procedure and whether education about the problems associated with base-rate neglect sensitized officers to variations in evidentiary connection. Police officers (N = 279; age range = 24-70; 86% male) read a hypothetical crime scenario, adopting the role of the lead investigator. The scenarios varied in how closely the suspect was connected to the crime (evidentiary connection: weak vs. strong). Before reading the crime scenarios, half of the participants received education about the relationship between the base rate of guilt among suspects placed in lineups and the prevalence of mistaken identifications (education: present vs. absent). Officers indicated whether they would conduct an identification procedure with a witness based on the evidence they currently had against the suspect. We expected that participants would better distinguish between the strong and weak evidentiary connection conditions when education was present than when it was absent. Education did not sensitize officers to the strength of the evidence connecting the suspect to the crime under investigation, but officers were sensitive to variations in evidentiary connection without benefit of the educational intervention. However, a majority of officers were willing to subject a suspect to an identification procedure even when there was no evidence connecting the suspect to the crime. Officers' decisions about placing suspects in lineups reflect some level of base-rate neglect that remained even after education about the importance of increasing the ratio of culprit-present to culprit-absent lineups for decreasing mistaken identifications. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Eyewitness identifications of multiple culprits: Disconfirming feedback following one lineup decision impairs identification of another culprit.

Eyewitnesses to multiple-culprit crimes are often asked to try to identify the culprits from different lineups during a police investigation. In 2 experiments (N = 557), we show that disconfirming feedback after an identification attempt for 1 culprit can impair identification performance on a subsequent lineup for a different culprit. In each experiment, witnesses viewed a simulated, 2-culprit crime, followed by 2 police lineups: A culprit-absent lineup for 1 culprit and either a culprit-present or culprit-absent lineup for the second culprit. Following the first lineup, witnesses received disconfirming feedback or no feedback. For witnesses who correctly rejected the first lineup, disconfirming feedback impaired identification performance on the subsequent lineup. For witnesses who incorrectly chose someone from the first lineup, disconfirming feedback impaired subsequent performance when the feedback unambiguously implied poor ability to identify the culprit in the first identification test (Experiment 2) but not when it could have been interpreted as implying poor criterion setting (Experiment 1). Across both experiments, disconfirming feedback also reduced the difference in confidence between correct and incorrect identifications. These results add to evidence that postidentification feedback can affect subsequent identification performance by influencing witnesses’ beliefs about their ability to identify a culprit. Current policy recommendations state that postidentification feedback should be withheld from witnesses until confidence has been documented. These should be updated to recommend withholding feedback for longer if the witness may be asked to view additional lineups, and to ensure that lineup administrators are blind to the results of any previous lineups.

Eyewitnesses' free-report verbal confidence statements are diagnostic of accuracy.

We assessed recent policy recommendations to collect eyewitnesses' confidence statements in witnesses' own words as opposed to numerically. We conducted an experiment to test whether eyewitnesses' free-report verbal confidence statements are as diagnostic of eyewitness accuracy as their numeric confidence statements and whether the diagnostic utility of eyewitnesses' verbal and numeric confidence statements varies across witnessing conditions. We hypothesized that eyewitnesses' verbal and numeric confidence statements are both significantly associated with identification accuracy among choosers and that their diagnostic utility holds across varying witnessing conditions. In the first phase of the experiment, eyewitnesses (N = 4,795 MTurkers; 48.8% female; 50.8% male; .3% other; age M = 36.9) viewed a videotaped mock-crime and made an identification decision from a culprit-present or culprit-absent lineup. We manipulated witnessing conditions at encoding and retrieval to obtain varied levels of memory performance. In the second phase of the experiment, evaluators (N = 456 MTurkers; 35.5% female; 62.7% male .4% other; age M = 36.5) translated witnesses' verbal confidence statements to a numeric estimate and we used calibration and confidence-accuracy characteristic analyses to compare the diagnosticity of witnesses' verbal and numeric confidence statements across the two levels of memory performance. Witnesses' verbal and numeric confidence statements were significantly and nondifferentially diagnostic of eyewitness accuracy for both choosers and nonchoosers, and their diagnostic utility held across variations in witnessing conditions. These findings suggest the applied utility of collecting either verbal or numeric confidence statements from eyewitnesses immediately following an identification decision. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

The importance of decision bias for predicting eyewitness lineup choices: toward a Lineup Skills Test

ᅟWe report on research on individual-difference measures that could be used to assess the validity of eyewitness identification decisions.BackgroundThe predictive utility of face recognition tasks for eyewitness identification has received some attention from psychologists, but the previous research focused primarily on witnesses’ likelihood of correctly choosing the culprit when present in a lineup. Far less discussed has been individual differences in witnesses’ proclivity to choose from a lineup that does not contain the culprit. We designed a two-alternative non-forced-choice face recognition task (consisting of mini-lineup test pairs, half old/new and half new/new) to predict witnesses’ proclivity to choose for a set of culprit-absent lineups associated with earlier-viewed crime videos.ResultsIn two studies involving a total of 402 participants, proclivity to choose on new/new pairs predicted mistaken identifications on culprit-absent lineups, with r values averaging .43. The likelihood of choosing correctly on old/new pairs (a measure of face recognition skill) was only weakly predictive of correct identifications in culprit-present lineups (mean r of .22).ConclusionsOur findings could be the basis for further research aimed at developing a standardized measure of proclivity to choose that could be used, along with other measures, to weigh eyewitnesses’ lineup identification decisions.

Eyewitness identification across the life span: A meta-analysis of age differences.

Lineup identifications are often a critical component of criminal investigations. Over the past 35 years, researchers have been conducting empirical studies to assess the impact of witness age on identification accuracy. A previous meta-analysis indicated that children are less likely than adults to correctly reject a lineup that does not contain the culprit, but children 5 years and older are as likely as adults to make a correct identification if the culprit is in the lineup (Pozzulo & Lindsay, 1998). We report an updated meta-analysis of age differences in eyewitness identification, summarizing data from 20,244 participants across 91 studies. Contrary to extant reviews, we adopt a life span approach and examine witnesses from early childhood to late adulthood. Children's increased tendency to erroneously select a culprit-absent lineup member was replicated. Children were also less likely than young adults to correctly identify the culprit. Group data from culprit-absent and culprit-present lineups were used to produce signal detection measures, which indicated young adults were better able than children to discriminate between guilty and innocent suspects. A strikingly similar pattern emerged for older adults, who had even stronger deficits in discriminability than children, relative to adults. Although identifications by young adults were the most reliable, identifications by all witnesses had probative value.

Seventy-two tests of the sequential lineup superiority effect: A meta-analysis and policy discussion.

A decade ago, a meta-analysis showed that identification of a suspect from a sequential lineup versus a simultaneous lineup was more diagnostic of guilt (Steblay, Dysart, Fulero, & Lindsay, 2001). Since then, controversy and debate regarding sequential superiority has emerged. We report the results of a new meta-analysis involving 72 tests of simultaneous and sequential lineups from 23 different labs involving 13,143 participant-witnesses. The results are very similar to the 2001 results in showing that the sequential lineup is less likely to result in an identification of the suspect, but also more diagnostic of guilt than is the simultaneous lineup. An examination of the full diagnostic design dataset (27 tests that used the full simultaneous/sequential culprit-present/culprit-absent design) showed that the average gap in correct identifications favoring the simultaneous lineup over the sequential lineup—8%—is smaller than the 15% figure obtained from the 2001 meta-analysis (and from the current full 72-test dataset). The lower error rate incurred for culprit-absent lineups with use of a sequential format remains consistent across the years, with 22% fewer errors than simultaneous lineups. A Bayesian analysis shows that the posterior probability of guilt following an identification of the suspect is higher for the sequential lineup across the entire base rate for culprit presence/absence. New ways to think about policy issues are discussed.

Do strict rules and moving images increase the reliability of sequential identification procedures?

AbstractLive identification procedures in England and Wales have been replaced by use of video, which provides a sequential presentation of facial images. Sequential presentation of photographs provides some protection to innocent suspects from mistaken identification when used with strict instructions designed to prevent relative judgements (Lindsay, Lea, & Fulford, 1991). However, the current procedure in England and Wales is incompatible with these strict instructions. The reported research investigated whether strict instructions would enhance the reliability of identification from video. The effect of using moving rather than still video clips was also investigated. Participants witnessed a live staged incident, and attempted to identify the culprit later from police video lineups, which were run double blind. Strict instructions produced a significantly lower rate of correct identifications in culprit present lineups, but did not significantly reduce the rate of mistaken identification in culprit absent lineups. Moving images yielded fewer mistaken identifications in culprit absent lineups. Copyright © 2006 John Wiley & Sons, Ltd.

An analysis of multiple choices in MSL lineups, and a comparison with simultaneous and sequential ones

Simultaneous lineups allow witnesses to compare lineup members, causing excessive mistaken identifications. Levi (1998b) has tested MSL lineups: they are sequential, larger, and allow multiple choices. [The MSL lineup was originally termed a Modified Sequential Lineup (Levi, 1998b). However, there are other modified sequential lineups.] Each factor decreases mistaken identifications. However, witnesses make fewer single choices of culprits. Sometimes witnesses choose suspects more confidently than any foil. This analysis examines such multiple choices in four experiments. They account for half of multiple choices with culprits. Few foils are chosen, and such responses are rare in culprit-absent lineups, no more than single choices. They are therefore identifications too. An experiment comparing simultaneous, sequential, and MSL lineups is also reported. The culprit was identified more in simultaneous lineups than in sequential ones. The simultaneous lineup had more mistaken choices than sequential and MSL lineups, whose results were identical. The simultaneous and sequential lineups were equally diagnostic, while the MSL lineup, four times larger, was more than four times more reliable.

Distorted retrospective eyewitness reports as functions of feedback and delay.

Participant-witnesses viewed a crime video and attempted to identify the culprit from a culprit-absent lineup. The 253 mistaken-identification eyewitnesses were randomly given confirming, disconfirming, or no feedback regarding their identifications. Feedback was immediate or delayed 48 hr, and measures were immediate or delayed 48 hr. Confirming, but not disconfirming, feedback led to distortions of eyewitnesses' recalled confidence, amount of attention paid during witnessing, goodness of view, ability to make out facial details, length of time to identification, and other measures related to the witnessing experience. Unexpectedly, neither delaying the measures nor delaying feedback for 48 hr moderated these effects. The results underscore the need for double-blind lineups and neutral assessments of eyewitnesses' certainty and other judgments prior to feedback.

Protecting innocent defendants, nailing the guilty: a modified sequential lineup

Can the traditional lineup procedure be modified in such a way as to still secure positive identifications of guilty persons while minimizing the risk of misidentifications? Witnesses interacted with a ‘culprit’ who they were later called upon to identify from a 20-person sequential video lineup. Both culprit-present and culprit-absent lineups were employed and witnesses could choose more than one suspect. In 61 culprit-present lineups 43% chose only the suspect, while in 93 culprit-absent lineups no-one did. In culprit-present lineups 25% chose him along with foils, while 5% did so in culprit-absent lineups. Larger lineup size, and the ability to make multiple choices, helped lower the probability of choosing only an innocent suspect. Using Baysian analysis, the probability that a chosen defendant was innocent, based on the lineup alone, equalled 0.03, compared to 0.258 in traditional lineups. © 1998 John Wiley & Sons, Ltd.