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The identification of criminal perpetrators by eyewitnesses is a staple form of evidence in courts of law. In the 1970s psychological scientists began a systematic study of eyewitness identification using controlled experiments, and much has been learned through thousands of lab studies about factors that put the reliability of eyewitness evidence at risk. Laboratory science has soundly established that the rate of mistaken identification varies as a function of conditions during the witnessed event, the retention interval, and the method of conducting an identification procedure. A useful distinction has been made between two types of factors that influence eyewitness accuracy: system and estimator variables. System variables are those that are (or could be) controlled to improve the accuracy of eyewitness reports, particularly through science-informed police procedures such as non-leading interview protocols, fair lineup structure, and double-blind lineups. Estimator variables influence eyewitness memory and accuracy but are not under the control of the criminal justice system, such as conditions during the crime event (e.g., lighting, distance, obstacles to view), aspects of the criminal (e.g., number of perpetrators, facial disguise), and characteristics of the witness (e.g., visual acuity, stress). One estimator variable—referred to as the weapon focus effect—describes the phenomenon in which the presence of a weapon at the scene of a crime impairs the witness’s memory for the perpetrator and other details of the crime. The basic idea is that the weapon captures the visual attention of the witness and thereby distracts witness attention from other important features of the visual scene such as the face of the perpetrator. The eyewitness is simply less able to adequately encode and subsequently recall details peripheral to the weapon. The weapon focus effect has garnered attention in labs and courtrooms over the more than forty years of eyewitness research. The cumulative body of weapon focus research provides support for the claim that the presence of a weapon draws the attention of an eyewitness. In doing so, this weapon focus can diminish the ability of the eyewitness to later recognize and describe the culprit.

An eyewitness to a crime may make a series of identification decisions about the same suspect as evidence is gathered and presented at trial. These repeated decisions may involve show-ups, mugshots, photo arrays, lineups, and in-court identifications. Repeated identification procedures increase suspect identifications but do not increase the likelihood that the identified person is guilty. Eyewitness memory can be irreparably compromised, with significant risk incurred for an innocent suspect. The first identification procedure influences a witness’ subsequent decisions and confidence, in violation of the legal expectation that an identification reflects witness memory for the crime only. The research supports two recommendations. (1) Repeated identification procedures using the same suspect should be avoided. (2) Identifications made from repeated procedures—beyond the first identification procedure—should not be considered reliable eyewitness evidence. The first eyewitness identification attempt is the one that counts and must have been conducted with a fair and unbiased procedure.

Objective Our objective was to assess Amendola and Wixted’s (Journal of Experimental Criminology, 2015b, this issue) response to our critique of their conclusions regarding simultaneous and sequential lineups.

Objective Our objective was to examine how Amendola and Wixted (A&W, 2014) arrived at their conclusion that eyewitness identifications of suspects from simultaneous lineups were supported better by corroborating evidence than were identifications from sequential lineups. Their cases came from a randomized field experiment by Wells et al. (2014).

Eyewitnesses (494) to actual crimes in 4 police jurisdictions were randomly assigned to view simultaneous or sequential photo lineups using laptop computers and double-blind administration. The sequential procedure used in the field experiment mimicked how it is conducted in actual practice (e.g., using a continuation rule, witness does not know how many photos are to be viewed, witnesses resolve any multiple identifications), which is not how most lab experiments have tested the sequential lineup. No significant differences emerged in rates of identifying lineup suspects (25% overall) but the sequential procedure produced a significantly lower rate (11%) of identifying known-innocent lineup fillers than did the simultaneous procedure (18%). The simultaneous/sequential pattern did not significantly interact with estimator variables and no lineup-position effects were observed for either the simultaneous or sequential procedures. Rates of nonidentification were not significantly different for simultaneous and sequential but nonidentifiers from the sequential procedure were more likely to use the "not sure" response option than were nonidentifiers from the simultaneous procedure. Among witnesses who made an identification, 36% (41% of simultaneous and 32% of sequential) identified a known-innocent filler rather than a suspect, indicating that eyewitness performance overall was very poor. The results suggest that the sequential procedure that is used in the field reduces the identification of known-innocent fillers, but the differences are relatively small.

Eyewitnesses' retrospective reports of certainty, view, attention, and other judgments constitute central variables used by courts to assess the credibility of eyewitness identification evidence. Recently, important state Supreme Court decisions (e.g., New Jersey v. Henderson, 2011; Oregon v. Lawson, 2012) have relied on psychological research regarding the post-identification feedback effect to revamp their assumptions about when witness retrospective self-reports can be trusted. The post-identification feedback effect, originally demonstrated by Wells and Bradfield (1998), refers to the way in which witness self-reports are distorted by feedback to the witnesses that suggests that their identifications were accurate or mistaken. We present a meta-analysis of the post-identification effect involving 7,000 participants from the United States, Canada, Europe, and Australia. The results show that confirming feedback robustly inflates eyewitnesses' retrospective judgments across experimental manipulations and laboratory settings with large effect sizes. We describe the policy implications of the feedback effect with regard to the need for double-blind lineup procedures. Moreover, we propose that testimony-relevant witness judgments should be collected and documented, preferably with videotape, before feedback can occur. We use moderator analyses to examine the current explanation of the feedback effect and delineate new research questions that could help develop a more complete theoretical understanding of the processes giving rise to the effect.

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.

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.

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.

Schacter et al. (2007, this issue) address the controversy surrounding an Illinois pilot project that attempted to compare sequential versus simultaneous police lineup formats. The statement by these experts will guide the design and execution of future field lineup experiments. This commentary discusses three aspects of field studies that pose challenges as lineup experiments are interpreted: the imprecise meaning of the dependent measure (eyewitness decisions), the limitations of single studies, and the necessity to devise public policy from incomplete knowledge. A combination of laboratory and field information provides the means to determine best practices in eyewitness identification procedures.

Research-based reforms for collecting eyewitness identification evidence (e.g., unbiased pre-lineup instructions, double-blind administration) have been proposed by psychologists and adopted in increasing numbers of jurisdictions across the United States. It is well known that reducing rates of mistaken identifications can also reduce accurate identification rates ( hits). But the reforms are largely designed to reduce the suggestiveness of the procedures they are meant to replace. Accordingly, we argue that it is misleading to label any hits obtained because of suggestive procedures as “hits” and then saddle reforms with the charge that they reduce the rate of these illegitimate hits. Eyewitness identification evidence should be based solely on the independent memory of the witness, not aided by biased instructions, cues from lineup administrators, or the use of lineup fillers who make the suspect stand out. Failure to call out these hits as being illegitimate can give solace to those who are motivated to preserve the status quo.

The effect on juror verdicts of judicial instructions to disregard inadmissible evidence was evaluated using meta-analysis. One hundred seventy-five hypothesis tests from 48 studies with a combined 8,474 participants were examined. Results revealed that inadmissible evidence (IE) has a reliable effect on verdicts consistent with the content of the IE. Judicial instruction to ignore the inadmissible evidence does not effectively eliminate IE impact. However, if judges provide a rationale for a ruling of inadmissibility, juror compliance may be increased. Contested evidence ruled admissible accentuates that information, resulting in a significant impact on verdicts. Suggestions for how the courts may mitigate the impact of inadmissible evidence more effectively are discussed.

Feedback administered to eyewitnesses after they make a line-up identification dramatically distorts a wide range of retrospective judgements (e.g. G. L. Wells & A. L. Bradfield, 1998 Journal of Applied Psychology, 83(3), 360–376.). This paper presents a meta-analysis of extant research on post-identification feedback, including 20 experimental tests with over 2400 participant-witnesses. The effect of confirming feedback (i.e. ‘Good, you identified the suspect’) was robust. Large effect sizes were obtained for most dependent measures, including the key measures of retrospective certainty, view and attention. Smaller effect sizes were obtained for so-called objective measures (e.g. length of time the culprit was in view) and comparisons between disconfirming feedback and control conditions. This meta-analysis demonstrates the reliability and robustness of the post-identification feedback effect. It reinforces recommendations for double-blind testing, recording of eyewitness reports immediately after an identification is made, and reconsideration by court systems of variables currently recommended for consideration in eyewitness evaluations. Copyright © 2006 John Wiley & Sons, Ltd.

Meta-analysis is used to compare identification accuracy rates in showups and lineups. Eight papers were located, providing 12 tests of the hypothesis and including 3013 participants. Results indicate that showups generate lower choosing rates than lineups. In target present conditions, showups and lineups yield approximately equal hit rates, and in target absent conditions, showups produce a significantly higher level of correct rejections. False identification rates are approximately equal in showups and lineups when lineup foil choices are excluded from analysis. Dangerous false identifications are more numerous for showups when an innocent suspect resembles the perpetrator. Function of lineup foils, assessment strategies for false identifications, and the potential impact of biases in lineup practice are suggested as additional considerations in evaluation of showup versus lineup efficacy.

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.

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.