Eyewitness decisions in simultaneous and sequential lineups: A dual-process signal detection theory analysis

Many eyewitness researchers have argued for the application of a sequential alternative to the traditional simultaneous lineup, given its role in decreasing false identifications of innocent suspects (sequential superiority effect). However, Ebbesen and Flowe (2002) have recently noted that sequential lineups may merely bring about a shift in response criterion, having no effect on discrimination accuracy. We explored this claim, using a method that allows signal detection theory measures to be collected from eyewitnesses. In three experiments, lineup type was factorially combined with conditions expected to influence response criterion and/or discrimination accuracy. Results were consistent with signal detection theory predictions, including that of a conservative criterion shift with the sequential presentation of lineups. In a fourth experiment, we explored the phenomenological basis for the criterion shift, using the remember-know-guess procedure. In accord with previous research, the criterion shift in sequential lineups was associated with a reduction in familiarity-based responding. It is proposed that the relative similarity between lineup members may create a context in which fluency-based processing is facilitated to a greater extent when lineup members are presented simultaneously.     

Configural and component processing in simultaneous and sequential lineup procedures

Configural processing supports accurate face recognition, yet it has never been examined within the context of criminal identification lineups. We tested, using the inversion paradigm, the role of configural processing in lineups. Recent research has found that face discrimination accuracy in lineups is better in a simultaneous compared to a sequential lineup procedure. Therefore, we compared configural processing in simultaneous and sequential lineups to examine whether there are differences. We had participants view a crime video, and then they attempted to identify the perpetrator from a simultaneous or sequential lineup. The test faces were presented either upright or inverted, as previous research has shown that inverting test faces disrupts configural processing. The size of the inversion effect for faces was the same across lineup procedures, indicating that configural processing underlies face recognition in both procedures. Discrimination accuracy was comparable across lineup procedures in both the upright and inversion condition. Theoretical implications of the results are discussed.     

Eyewitness identification in simultaneous and sequential lineups: an investigation of position effects using receiver operating characteristics

For decades, sequential lineups have been considered superior to simultaneous lineups in the context of eyewitness identification. However, most of the research leading to this conclusion was based on the analysis of diagnosticity ratios that do not control for the respondent’s response criterion. Recent research based on the analysis of ROC curves has found either equal discriminability for sequential and simultaneous lineups, or higher discriminability for simultaneous lineups. Some evidence for potential position effects and for criterion shifts in sequential lineups has also been reported. Using ROC curve analysis, we investigated the effects of the suspect’s position on discriminability and response criteria in both simultaneous and sequential lineups. We found that sequential lineups suffered from an unwanted position effect. Respondents employed a strict criterion for the earliest lineup positions, and shifted to a more liberal criterion for later positions. No position effects and no criterion shifts were observed in simultaneous lineups. This result suggests that sequential lineups are not superior to simultaneous lineups, and may give rise to unwanted position effects that have to be considered when conducting police lineups.     

Enhancing lineup identification accuracy: two codes are better than one

Ways of improving identification accuracy were explored by comparing the conventional visual lineup with an auditory/visual lineup, one that paired color photographs with voice recordings. This bimodal lineup necessitated sequential presentation of lineup members; Experiment 1 showed that performance in sequential lineups was better than performance in traditional simultaneous lineups. In Experiments 2A and 2B unimodal and bimodal lineups were compared by using a multiple-lineup paradigm: Ss viewed 3 videotaped episodes depicting standard police procedures and were tested in 4 sequential lineups. Bimodal lineups were more diagnostic than either visual or auditory lineups alone. The bimodal lineup led to a 126% improvement in number of correct identifications over the conventional visual lineup, with no concomitant increase in number of false identifications. These results imply strongly that bimodal procedures should be adopted in real-world lineups. The nature of memorial processes underlying this bimodal advantage is discussed.     

Unravelling the effects of sequential presentation in culprit‐present lineups

It is well established that sequential presentation of faces in an eyewitness situation can reduce false identification rates. The effect of a sequential presentation on the probability of accurately identifying a culprit when present in a lineup is less clear. The current study examined the efficacy of the sequential procedure in culprit present lineups approximating the real life condition where a person's appearance has changed between the time they were seen and the identification. Young (17–33 years) and older (58–80 years) witnesses viewed a video of a crime and then engaged in some filler tasks. Later they viewed a culprit‐present lineup presented in a simultaneous or sequential format. Some witnesses viewed lineups in which target appearance (hairstyle) had changed and some where it had not. Sequential testing was associated with fewer choices (hits and foil choices) as compared to simultaneous testing. A change of appearance lowered hit rates in sequential test conditions among young adults. Finally, participants in sequential conditions were more likely to report that they expected the target to be present in the lineup. We advise policy makers not to advocate sequential testing until we have a full understanding of the conditions under which the sequential‐superiority effect may be observed. Copyright © 2003 John Wiley & Sons, Ltd.     

Showups versus lineups: An evaluation using ROC analysis

Showups (a one-person identification) were compared to both simultaneous and sequential lineups that varied in lineup fairness and the position of the suspect in the lineup. We reanalyzed data from a study by Gronlund, Carlson, Dailey, and Goodsell (2009), which included simultaneous and sequential lineups, and using the same stimuli and procedures, collected new data using showup identifications. Performance was compared using ROC analysis, which is superior to traditional measures such as correct and false identification rates, and probative value measures. ROC analysis showed that simultaneous lineups consistently produced more accurate identification evidence than showups, but sequential lineups were sometimes no more accurate than showups, and were never more accurate than simultaneous lineups. These results supported prior suppositions regarding the suggestiveness of showups, revealed a misconception about the superiority of sequential lineups, and demonstrated why eyewitness identification procedures need to be evaluated using ROC analyses.     

The Effect of Backloading Instructions on Eyewitness Identification from Simultaneous and Sequential Lineups

The sequential lineup is multifaceted, including serial presentation of faces, multiple decisions, and often backloading (indicating to an eyewitness that a lineup contains more photos than there actually are). We evaluated the effect of backloading instructions on response bias and sensitivity with an eyewitness identification paradigm. Importantly, we included an ‘undisclosed’ condition that provided no information to participants about the number of lineup members to expect. Experiment 1 (N = 780) tested sequential lineups; Experiment 2 (N = 532) tested simultaneous lineups. As predicted, signal detection analysis showed that backloading induced participants to be more conservative in choosing from both lineup types, but did not affect d′. We conclude that the criminal justice system should be mindful of this shift in response bias, as it has implications for both guilty and innocent suspect identifications. Copyright © 2016 John Wiley & Sons, Ltd.     

A position of influence: Variation in offender identification rates by location in a lineup

Researchers have identified several threats to the validity of the use of the lineup as a test of true recognition. One concern is related to the structure of the simultaneous lineup. It is argued here that a simultaneous presentation of an array nonetheless requires the viewer to undertake sequential processing of the items in the array. This sequential pattern is unlikely to be random and therefore the position of a culprit in a lineup may have a significant effect on the accuracy of witness selection. A simulated crime (snatching of a handbag) was shown to a convenience sample of 84 undergraduates aged between 18–23 years. In 84 subsequent live lineups, the offender was placed with four foils. He was positioned on the far left (position 1) in 42 cases (50%), and in 14 cases respectively in positions 3 (centre), 4 (centre right) and 5 (extreme right). A very strong association was found between position and correct identification with position 1 placement leading to a significantly lower proportion of correct identification (7.1%) compared to position 3 (50.0%), position 4 (64.3%), and position 5 (21.4%). Steps to remedy possible positional biases are considered. Copyright © 2009 John Wiley & Sons, Ltd.     

Simultaneous and sequential lineups: decision processes of accurate and inaccurate eyewitnesses

The cognitive processes and decision‐making strategies of eyewitnesses were tested for their predictive qualities in determining the accuracy of identifications from lineups. The sequential lineup presentation was compared with the traditionally employed simultaneous lineup under culprit (target) present and culprit absent conditions. Consistent with previous research the sequential presentation resulted in an equivalent number of correct identifications compared to the simultaneous lineup but reduced false identification rates. Although sequential lineups were found to be associated with the use of absolute strategies, those shown a simultaneous lineup reported the use of both relative and absolute strategies. Accurate identifications and rejections were found to be associated with the use of absolute strategies, irrespective of lineup presentation or presence of target. Also accurate identifications, at least with a sequential lineup, were generally made faster than inaccurate identifications. These results are compared to previous studies with respect to the effect that mode of processing (relative versus absolute judgements) has on a witness's decision making and identification accuracy. Copyright © 2001 John Wiley & Sons, Ltd.     

An evaluation of lineup presentation,weapon presence,and a distinctive feature using ROC analysis

We conducted an experiment (N = 2675) including both laboratory and online participants to test hypotheses regarding important system and estimator variables for eyewitness identification. Simultaneous lineups were compared to sequential lineups with the suspect presented early versus late because there is evidence that suspect position could be an important factor determining a simultaneous versus sequential advantage in guilty-innocent suspect discriminability. We also manipulated whether or not the perpetrator held a weapon or had a distinctive feature on his face, to re-evaluate recent evidence that these factors interact. Overall, the simultaneous lineup yielded higher discriminability than the sequential lineup, and there was no effect of sequential position. Discriminability was higher when the perpetrator had no weapon, but only when no distinctive feature was present. We conclude with a discussion of the importance of exploring interactions between system and estimator variables using Receiver Operating Characteristic (ROC) analysis.     

The not‐sure response option in sequential lineup practice

Field implementation of double‐blind sequential lineups has prompted a question about the impact on eyewitness decisions of an explicit not‐sure response option. In this laboratory study, a video crime was viewed by 378 participants who then attempted to identify the culprit from a six‐person sequential or simultaneous‐format lineup that either included or did not include the culprit. Witnesses were provided either dichotomous forced‐choice (FC) response categories (yes/no) or a not‐sure option as one of three response categories (yes/no/not‐sure). The not‐sure option (NSO) significantly decreased witness choosing compared to the FC condition but only for sequential lineups. Both correct identifications and false alarms decreased. Diagnosticity was greatest for a sequential lineup with a NSO. The results suggest a criterion decision shift for witnesses who view a sequential lineup with a not‐sure response option. Copyright © 2010 John Wiley & Sons, Ltd.     

Lineup composition, suspect position, and the sequential lineup advantage

N. M. Steblay, J. Dysart, S. Fulero, and R. C. L. Lindsay (2001) argued that sequential lineups reduce the likelihood of mistaken eyewitness identification. Experiment 1 replicated the design of R. C. L. Lindsay and G. L. Wells (1985), the first study to show the sequential lineup advantage. However, the innocent suspect was chosen at a lower rate in the simultaneous lineup, and no sequential lineup advantage was found. This led the authors to hypothesize that protection from a sequential lineup might emerge only when an innocent suspect stands out from the other lineup members. In Experiment 2, participants viewed a simultaneous or sequential lineup with either the guilty suspect or 1 of 3 innocent suspects. Lineup fairness was varied to influence the degree to which a suspect stood out. A sequential lineup advantage was found only for the unfair lineups. Additional analyses of suspect position in the sequential lineups showed an increase in the diagnosticity of suspect identifications as the suspect was placed later in the sequential lineup. These results suggest that the sequential lineup advantage is dependent on lineup composition and suspect position.     

Double Exposure: The Effects of Repeated Identification Lineups on Eyewitness Accuracy

Eyewitnesses may be asked to identify the same suspect from a lineup on successive occasions. This study explored the effects on eyewitness decisions of repeated same‐suspect lineups, within a 2 × 2 × 2 mixed‐model factorial design. Witnesses to a video crime attempted to identify the culprit from two same‐format lineups (simultaneous or sequential) separated by a 2‐week retention interval (Lineup1, Lineup2) in which a suspect (guilty or innocent) was common to the lineups. We predicted two components of a posited repeated lineup effect: that positive identification errors made at the first lineup would be carried forward rather than corrected at the second lineup and that the number of false identifications of the innocent suspect would rise from first to second lineup. Predictions were supported, with a stronger negative impact of repeated lineups for simultaneous than sequential lineups. Additionally, witnesses who made selections of the guilty suspect and of the innocent suspect at Lineup2 were equally confident and were significantly more confident than witnesses who declined to pick. The results underscore concerns about possible negative outcomes from repeated lineups. Copyright © 2013 John Wiley & Sons, Ltd.     

Non‐blind lineup administration biases administrators' interpretations of ambiguous witness statements and their perceptions of the witness

Administering lineups “blind”—whereby the administrator does not know the identity of the suspect—is considered part of best practices for lineups. The current study tests whether non‐blind lineup administrators would evaluate ambiguous eyewitness statements, and the witness himself or herself, in a manner consistent with their beliefs. College students (n = 219) were told the identity of the suspect or not before administering a lineup to a confederate‐witness who made an ambiguous response (e.g., “it could be #3 but I'm not sure”). When ambiguous witness statements matched administrators' beliefs regarding the suspect (compared with when they mismatched administrators' beliefs, or administrators had no belief), administrators (a) were significantly more likely to record the statement as an identification (as opposed to a “not sure” response); (b) were significantly less likely to make statements that might lead the witness away from the suspect; and (c) evaluated the witness's viewing conditions significantly more positively.     

Sequential lineups: shift in criterion or decision strategy?

R. C. L. Lindsay and G. L. Wells (1985) argued that a sequential lineup enhanced discriminability because it elicited use of an absolute decision strategy. E. B. Ebbesen and H. D. Flowe (2002) argued that a sequential lineup led witnesses to adopt a more conservative response criterion, thereby affecting bias, not discriminability. Height was encoded as absolute (e.g., 6 ft [1.83 m] tall) or relative (e.g., taller than). If a sequential lineup elicited an absolute decision strategy, the principle of transfer-appropriate processing predicted that performance should be best when height was encoded absolutely. Conversely, if a simultaneous lineup elicited a relative decision strategy, performance should be best when height was encoded relatively. The predicted interaction was observed, providing direct evidence for the decision strategies explanation of what happens when witnesses view a sequential lineup.     

A comparison of presentation methods of video identification parades

Researchers have demonstrated that sequential lineup presentation reduces false identifications from perpetrator absent lineups. In England and Wales police identification parades are shown on video in a sequential manner. However, police sequential presentation varies from the strict sequential presentation advocated by researchers. In addition, after police have shown the sequential presentation they also have the option to show witnesses a matrix of the parade where witnesses can see all members of the parade simultaneously. The research reported investigated the effect of strict sequential presentation, police sequential presentation and police sequential presentation plus matrix on mock witnesses' performance on perpetrator present and absent video identification parades. Strict sequential presentation led to fewer correct identifications of the perpetrator than police sequential and police sequential plus matrix, with no difference in performance between either of the police conditions. For perpetrator absent lineups there was no effect of lineup presentation condition on lineup performance. Copyright © 2010 John Wiley & Sons, Ltd.     

Divergent viewpoints about lineups: What policy for the identification of criminals?

IntroductionA fair lineup is needed to maximize the likelihood of correct identification of the criminal and minimize the likelihood of mistaken identification. Fairness depends on distractor plausibility and the lineup method (i.e., simultaneous or sequential).ObjectiveThis paper aims to evaluate the advantages and the limits of distractor plausibility and the presentation of the lineup members, and thus show the best method to ensure correct identification.MethodOur conclusions are based on the major experiments published in the field and on recent debates in the scientific community.Results and conclusionIn addition to distractor plausibility, our conclusions, which are based on previous work by Malpass (2006), suggest that sequential and simultaneous lineups are complementary rather than opposed. The paper argues that two tools specifically designed for and adapted to particular situations are better than one.     

Identification accuracy of a single culprit in a multiple-perpetrator mock crime

IntroductionEyewitness identification research has mainly examined the identification accuracy of a single perpetrator but many actual crimes involve not one but several perpetrators.ObjectiveThe aim of the study was to examine the identification accuracy if only one lineup for one of the two perpetrators is presented in a multiple perpetrator crime.MethodThe sample consisted of 180 participants who saw a theft video followed by distraction tasks. One group of participants saw lineups for both of the perpetrators (one target present and one target-absent) whereas the other saw only a single lineup (either target-present or target-absent) for one of the two perpetrators.ResultsParticipants who saw a single lineup did not make more inaccurate identification decisions then participants who saw two lineups. Decision accuracy in the first lineup was not associated with the decision accuracy in the second lineup.ConclusionThe results are discussed in terms of the number of perpetrators and line-up presentation types.