On the Diagnosticity of Multiple-Witness Identifications

It is not uncommon for there to be multiple eyewitnesses to a crime, each of whom is later shown a lineup. How is the probative value, or diagnosticity, of such multiple-witness identifications to be evaluated? Previous treatments have focused on the diagnosticity of a single eyewitness’s response to a lineup (Wells and Lindsay, Psychol. Bull. 3 (1980) 776); however, the results of eyewitness identification experiments indicate that the responses of multiple independent witnesses may often be inconsistent. The present paper calculates response diagnosticity for multiple witnesses and shows how diagnostic probabilities change across various combinations of consistent and inconsistent witness responses. Multiple-witness diagnosticity is examined across variation in the conditions of observation, lineup composition, and lineup presentation. In general, the diagnostic probabilities of guilt were shown to increase with the addition of suspect identifications and decrease with the addition of nonidentifications. Foil identification results were more complicated-diagnostic of innocence in many cases, but nondiagnostic or diagnostic of innocence in biased lineups. These analyses illustrate the importance of securing clear records of all witness responses, rather than myopically focusing on the witness who identified the suspect while ignoring those witnesses who did not.     

Does Lineup Size Matter with Child Witnesses

Children’s (N = 89) identification accuracy was examined as a function of lineup size. Participants (8–13 years) viewed a videotaped staged event, described what was witnessed and then were presented with either a target-present or—absent lineup containing 6 versus 12 lineup members. The elimination lineup procedure (Pozzulo and Lindsay J Appl Psychol 38: 2195–2209 1999) was used to present lineups. No significant differences in correct identification rates were found across the target-present sized lineups. In addition, the target was likely to “survive” at a comparable rate regardless of lineup size. Moreover, there was no significant difference in correct rejection rate as a function of lineup size. The non significance of these data are critical given that most research with child witnesses uses 6-person lineups whereas in many real world contexts larger sized lineups are used (e.g., 12-person in Canada).     

Sequential Lineup Laps and Eyewitness Accuracy

Police practice of double-blind sequential lineups prompts a question about the efficacy of repeated viewings (laps) of the sequential lineup. Two laboratory experiments confirmed the presence of a sequential lap effect: an increase in witness lineup picks from first to second lap, when the culprit was a stranger. The second lap produced more errors than correct identifications. In Experiment 2, lineup diagnosticity was significantly higher for sequential lineup procedures that employed a single versus double laps. Witnesses who elected to view a second lap made significantly more errors than witnesses who chose to stop after one lap or those who were required to view two laps. Witnesses with prior exposure to the culprit did not exhibit a sequential lap effect.     

Eyewitness Accuracy Rates in Sequential and Simultaneous Lineup Presentations: A Meta-Analytic Comparison

Most police lineups use a simultaneous presentation technique in which eyewitnesses view all lineup members at the same time. Lindsay and Wells (R. C. L. Lindsay & G. L. Wells, 1985) devised an alternative procedure, the sequential lineup, in which witnesses view one lineup member at a time and decide whether or not that person is the perpetrator prior to viewing the next lineup member. The present work uses the technique of meta-analysis to compare the accuracy rates of these presentation styles. Twenty-three papers were located (9 published and 14 unpublished), providing 30 tests of the hypothesis and including 4,145 participants. Results showed that identification of perpetrators from target-present lineups occurs at a higher rate from simultaneous than from sequential lineups. However, this difference largely disappears when moderator variables approximating real world conditions are considered. Also, correct rejection rates were significantly higher for sequential than simultaneous lineups and this difference is maintained or increased by greater approximation to real world conditions. Implications of these findings are discussed.     

Exploring the Sequential Lineup Advantage Using WITNESS

Advocates claim that the sequential lineup is an improvement over simultaneous lineup procedures, but no formal (quantitatively specified) explanation exists for why it is better. The computational model WITNESS (Clark, Appl Cogn Psychol 17:629–654, 2003) was used to develop theoretical explanations for the sequential lineup advantage. In its current form, WITNESS produced a sequential advantage only by pairing conservative sequential choosing with liberal simultaneous choosing. However, this combination failed to approximate four extant experiments that exhibited large sequential advantages. Two of these experiments became the focus of our efforts because the data were uncontaminated by likely suspect position effects. Decision-based and memory-based modifications to WITNESS approximated the data and produced a sequential advantage. The next step is to evaluate the proposed explanations and modify public policy recommendations accordingly.     

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

Abstract

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.     

The information gained from witnesses' responses to an initial "blank" lineup

Wells ("The psychology of lineup identifications," Journal of Applied Social Psychology, 1984, 14, 89-103) proposed that a blank lineup (an initial lineup of known-to-be-innocent foils) can be used to screen eyewitnesses; witnesses who chose from a blank lineup (initial choosers) were more likely to make an error on a second lineup that contained a suspect than were witnesses who rejected a blank lineup (initial nonchoosers). Recent technological advances (e.g., computer-administered lineups) may overcome many of the practical difficulties cited as a barrier to the use of blank lineups. Our research extended knowledge about the blank lineup procedure by investigating the underlying causes of the difference in identification performance between initial choosers and initial nonchoosers. Studies 1a and 1b (total, N = 303) demonstrated that initial choosers were more likely to reject a second lineup than initial nonchoosers and witnesses who did not view a blank lineup, implying that cognitive biases (e.g., confirmation bias and commitment effects) influenced initial choosers' identification decisions. In Study 2 (N = 200), responses on a forced-choice identification test provided evidence that initial choosers have, on average, poorer memories for the culprit than do initial nonchoosers. We also investigated the usefulness of blank lineups for interpreting identification evidence. Diagnosticity ratios suggested that suspect identifications made by initial nonchoosers (cf. initial choosers) should have a greater impact on estimates of the likely guilt of the suspect. Furthermore, for initial nonchoosers, higher confidence in blank lineup rejections was associated with higher diagnosticity for subsequent suspect identifications. These results have implications for policy to guide the collection and interpretation of identification evidence. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

What We Know Now: The Evanston Illinois Field Lineups

A Freedom of Information Act lawsuit secured 100 eyewitness identification reports from Evanston, Illinois, one of three cities of the Illinois Pilot Program. The files provide empirical evidence regarding three methodological aspects of the Program’s comparison of non-blind simultaneous to double-blind sequential lineups. (1) A-priori differences existed between lineup conditions. For example, the simultaneous non-blind lineup condition was more likely to involve witnesses who had already identified the suspect in a previous lineup or who knew the offender (non-stranger identifications), and this condition also entailed shorter delays between event and lineup. (2) Verbatim eyewitness comments were recorded more often in double-blind sequential than in non-blind simultaneous lineup reports (83% vs. 39%). (3) Effective lineup structure was used equally in the two lineup conditions.     

PC_Eyewitness and the Sequential Superiority Effect: Computer-Based Lineup Administration

Computer technology has become an increasingly important tool for conducting eyewitness identifications. In the area of lineup identifications, computerized administration offers several advantages for researchers and law enforcement. PC_Eyewitness is designed specifically to administer lineups. To assess this new lineup technology, two studies were conducted in order to replicate the results of previous studies comparing simultaneous and sequential lineups. One hundred twenty university students participated in each experiment. Experiment 1 used traditional paper-and-pencil lineup administration methods to compare simultaneous to sequential lineups. Experiment 2 used PC_Eyewitness to administer simultaneous and sequential lineups. The results of these studies were compared to the meta-analytic results reported by N. Steblay, J. Dysart, S. Fulero, and R. C. L. Lindsay (2001). No differences were found between paper-and-pencil and PC_Eyewitness lineup administration methods. The core findings of the N. Steblay et al. (2001) meta-analysis were replicated by both administration procedures. These results show that computerized lineup administration using PC_Eyewitness is an effective means for gathering eyewitness identification data.     

Non-biased lineup instructions do matter – a problem for older witnesses

Abstract

From the limited literature on older witnesses’ identification performance it is known that they are less accurate on lineups compared to younger witnesses. What is less certain is why they show this age deficit and what can be done to aid their performance. Witnesses forgot being given non-biased lineup instructions informing witnesses that the perpetrator may or may not be present. More older witnesses than younger witnesses forgot and witnesses who failed to report remembering these instructions were significantly less accurate on the lineups. In addition, the current study investigated the use of sequential lineup presentation and stringent decision criteria to aid the performance of older witnesses. Sequential presentation was beneficial to both younger and older adults when the lineup was target absent (TA) but was detrimental when the lineup was target present (TP). Stringent decision criteria had no significant beneficial effect. Future directions for aiding older witnesses’ performance are discussed.     

Much better than the sequential lineup: a 120-person lineup

Abstract

Large lineups may be more reliable than small ones. However, research has found greatly reduced identifications in 40-person lineups of photos shown sequentially one at a time. The task may be more difficult than necessary. Grouping photos may provide an easier one. Three studies had compared seven-page lineups (42, 84, or 168 members) with lineups of about 20. In the first two studies identification and mistaken choice rates were identical in the large and smaller lineup. Identifications in the 168-person lineup were much less. This study tested a 10-page 120-person lineup, and added a 12-person lineup. No difference was found between the 120- and 24-person lineups, and an interaction in 12-person lineups was found between graduate lab student witnesses and others. False identifications, and the probability that the suspect is innocent when ‘identified’, is much less in 120-person lineups than the 24- or 12-person lineups, or the sequential lineup.     

Instruction Bias and Lineup Presentation Moderate the Effects of Administrator Knowledge on Eyewitness Identification

Pairs (N = 234) of witnesses and lineup administrators completed an identification task in which administrator knowledge, lineup presentation, instruction bias, and target presence were manipulated. Administrator knowledge had the greatest effect on identifications of the suspect for simultaneous photospreads paired with biased instructions, with single-blind administrations increasing identifications of the suspect. When biased instructions were given, single-blind administrations produced fewer foil identifications than double-blind administrations. Administrators exhibited a greater proportion of biasing behaviors during single-blind administrations than during double-blind administrations. The diagnosticity of identifications of the suspect in double-blind administrations was double their diagnosticity in single-blind administrations. These results suggest that when biasing factors are present to increase a witness’s propensity to guess, single-blind administrator behavior influences witnesses to identify the suspect.     

Response to Lindsay,Mansour, Beaudry,Leach and Bertrand's Sequential lineup presentation: Patterns and policy

This paper is a response to the earlier paper by Lindsay, Mansour, Beaudry, Leach and Bertrand (2009). We argue that eyewitness research is an important public good and that high‐quality in research and policy formulations offered to the public interest is required to maintain our standing of trust. We argue that even though sequential lineups have been successfully codified in some jurisdictions as the exclusive eyewitness identification procedure, the claim of sequential superiority is built upon errors in the research process and that the evidence of reduced false identification with sequential lineups is completely offset by reductions in correct identifications. We reject the idea that the loss of correct identifications can be dismissed as guessing on the basis that this is speculative and that there is no published empirical support for the idea. We reject the idea that false identifications are necessarily more valuable for society to reduce than are correct identifications to achieve. Improvements in eyewitness identification are important, and interesting lines of investigation are available. It is questionable whether the sequential lineup is important among them.     

A Preidentification Questioning Effect: Serendipitously Increasing Correct Rejections

A study designed to test the effects of delay between crime and lineup on identification accuracy produced an unusually high rate of correct rejection from target-absent, simultaneous lineups (J. E. Dysart, 1999). Examining the procedures indicated that one question included in a preidentification questionnaire differed from those used previously. The question asked witnesses if they believed they would be able to correctly reject a target-absent lineup. An experiment (N = 138) was conducted to explore the impact of preidentification questions, including this new question, on witness accuracy. Results revealed that asking witnesses these questions, prior to viewing the lineup, significantly increased correct rejections of target-absent simultaneous lineups.     

Lineup Administrators' Expectations: Their Impact on Eyewitness Confidence

This research focuses on how lineup a administrators influence eyewitnesses' postidentification confidence. What happens to witness confidence when a witness makes an identification that confirms the lineup administrator's expectations; what happens when this expectation is not confirmed? In Experiment 1, participant interviewers (n = 52) administered target-absent photo lineups to participant witnesses (n = 52). The interviewers did not view the simulated crime, but were told the thief's position in the lineup. In every instance this information was false (we used a target-absent lineup). A one-way ANOVA revealed that eyewitness identification confidence was malleable as a function of interviewers' beliefs about the thief's identity. In Experiment 2, participant jurors (n = 80) viewed 40 testimonies of Experiment 1 witnesses (2 participants viewed each testimony). Participant jurors judged all participant witnesses as equally credible despite their varying levels of postidentification confidence.

     

Probative Value of Absolute and Relative Judgments in Eyewitness Identification

It is well-accepted that eyewitness identification decisions based on relative judgments are less accurate than identification decisions based on absolute judgments. However, the theoretical foundation for this view has not been established. In this study relative and absolute judgments were compared through simulations of the WITNESS model (Clark, Appl Cogn Psychol 17:629–654, 2003) to address the question: Do suspect identifications based on absolute judgments have higher probative value than suspect identifications based on relative judgments? Simulations of the WITNESS model showed a consistent advantage for absolute judgments over relative judgments for suspect-matched lineups. However, simulations of same-foils lineups showed a complex interaction based on the accuracy of memory and the similarity relationships among lineup members.     

Predictors of eyewitness identification decisions from video lineups in England: A field study

Eyewitness identification decisions from 1,039 real lineups in England were analysed. Identification procedures have undergone dramatic change in the United Kingdom over recent years. Video lineups are now standard procedure, in which each lineup member is seen sequentially. The whole lineup is seen twice before the witness can make a decision, and the witness can request additional viewings of the lineup. A key aim of this paper was to investigate the association between repeated viewing and eyewitness decisions. Repeated viewing was strongly associated with increased filler identification rates, suggesting that witnesses who requested additional viewings were more willing to guess. In addition, several other factors were associated with lineup outcomes, including the age difference between the suspect and the witness, the type of crime committed, and delay. Overall, the suspect identification rate was 39%, the filler identification rate was 26% and the lineup rejection rate was 35%. (PsycINFO Database Record (c) 2012 APA, all rights reserved).