Effective size and defendant bias in eyewitness identification lineups

Two aspects of fairness in eyewitness identification lineups are discussed: the effective size of a lineup, and the degree of bias towards or away from the defendant. Procedures are proposed for measuring both aspects of lineup fairness and a range of hypothetical examples is given. An appendix discusses and explains procedural and computational details, and provides a table of critical ranges of identification proportions for lineups of varying sizes and for different numbers of observers.     

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).     

Accuracy of eyewitness identifications in showups and lineups

Experiment 1 tested one-person and six-person photographic lineup identifications in field situations either immediately, or 30 minutes, or 2 hours, or 24 hours after a 15-second ordinary encounter with a target. Accuracy of performance was superior in six-person lineups than in showups over time. False identifications of a lookalike innocent suspect were significantly greater in showups than in six-person lineups, especially when the suspect wore the same clothing as the culprit. Experiment 2 followed the same research design as Experiment 1, except that only live showup identifications were tested and, in addition, a physically dissimilar innocent suspect was shown to witnesses. The dissimilar innocent suspect was consistently and correctly rejected in the target-absent showup. Hit rates for live suspects were relatively low over the 24-h retention interval. Correct rejections significantly exceeded false identifications only on the immediate test. The lookalike innocent suspect was readily rejected when different clothing was worn at the test. No significant differences were found in hit scores or in confidence-accuracy scores between live and photographic targets. Confidence-accuracy correlations were significant but low across experimental conditions.     

Realism and eyewitness identification research

The importance of realism in eyewitness identification research is examined as the basis for both the credibility and utility of the information it provides. Without knowledge of how laboratory eyewitnesses behave differently from real eyewitnesses, the relevance and external validity of identification studies may be questioned. Factors differentiating these identification contexts are discussed. Witnesses in identification studies are in social decision-making contexts similar to those of real eyewitnesses when their decision to choose someone or to reject the lineup may have a significant impact on others' lives. Two studies are reported which preserve aspects of realism. Both presented witnesses with a realistic vandalism. The second maintained realism through the identification situation. The first study demonstrated effects of biased instructions on witnesses' willingness to make a lineup choice and on identification errors (with the offender present and absent). The second study showed an unexpected preference of witnesses for making an identification when the supposed consequences for the suspect were to be severe. To evaluate the generalizability and utility of laboratory studies it is important to determine whether their results and related theoretical analyses survive the transposition to more realistic contexts. Realistic studies should serve as benchmarks against which simulations are compared and their generalizability evaluated.     

Improving eyewitness identification accuracy by screening out those who say they don't know

Improving eyewitness identification evidence remains a key priority for research. Basic laboratory research has consistently demonstrated that allowing participants to withhold answers about which they are unsure leads to improved accuracy. Surprisingly, this approach has not been the subject of comprehensive investigation in the eyewitness identification literature. In this article, we explored the utility of allowing uncertain witnesses to opt out of an identification decision, by providing an explicit don't know option. Further, we contrasted the rate of use of this explicit option with the frequency that participants spontaneously withheld a decision when asked to respond in their own words. Four hundred and twenty participants witnessed a mock crime video before being presented with a showup of the perpetrator or an innocent suspect. Participants were tested either immediately or after a 3-week delay, with one of the three report options: Participants either made their choice in their own words (spontaneous report), chose between identifying and rejecting the showup (forced-report), or chose between identification, rejection and don't know (free-report). Only 2.2% of witnesses spontaneously used a don't know response, compared to 19.3% who used it when the option was explicit. Compared with the forced-report decisions, free-report decisions were more accurate, more diagnostic of the suspect's guilt or innocence, and came at no cost to the number of correct decisions rendered. These data suggest that utilisation of an explicit don't know option may be of practical value.     

Children's eyewitness identification performance: Effects of a Not Sure response option and accuracy motivation

Purpose. Children who witness crimes are sometimes asked to view a photospread lineup to see if they can identify the culprit. Here, we examined the effectiveness of two manipulations designed to assist in overcoming the tendency of child eyewitnesses to choose from lineups, a tendency that manifests in false identifications from target‐absent lineups. Methods. Children aged around 12 years (N = 432) were randomly assigned to control, Not Sure, or accuracy motivation conditions in order to examine both target‐absent and ‐present identification test performance across multiple sets of stimulus materials. Results. The Not Sure option did not affect false alarms or hit rates, but the combination of accuracy motivating conditions and the Not Sure option reduced guessing, with overall rates of false identifications falling by 12.2%. The latter effect was much stronger under some stimulus conditions but not detectable under others, indicating that the manipulations could improve but not impair performance. While there were beneficial effects at the group level, the manipulation did not produce a general change in individual children's decision strategies. Conclusions. Eyewitness identification test manipulations that reliably reduce false alarms, without lowering hits, by child witnesses have not yet been identified. Here, we showed how a simple‐to‐implement accuracy motivation manipulation reduces false alarms under some conditions, while also highlighting the importance of evaluating the efficacy of interventions across varied encoding and test conditions. However, developing a procedure that can produce a generalized improvement in decision making at the individual level remains a major challenge for eyewitness researchers.     

The reliability of eyewitness identification

This study examines the effects of 14 estimator variables (e.g., disguise of robber, exposure time, weapon visibility) and system variables (e.g., lineup instructions, exposure to mugshots) on a number of measures of eyewitness performance: identification accuracy, choosing rates, confidence in lineup choice, relation between confidence and identification accuracy, memory for peripheral details, memory for physical characteristics of target, and time estimates. Subjects viewed a videotaped reenactment of an armed robbery and later attempted an identification. Characteristics of the videotape and lineup task were manipulated. Prominent findings were as follows: identification accuracy was affected by both estimator and system variables including disguise of robber, weapon visibility, elaboration instructions, and lineup instructions. Memory for peripheral details was positively correlated with choosing on the identification task but negatively correlated with identification accuracy.     

Influence of confidence inflation and explanations for changes in confidence on evaluations of eyewitness identification accuracy

Guidelines for conducting police line‐ups typically recommend immediate assessment of eyewitness confidence following identification. This confidence level can presumably be used to estimate accuracy even in the presence of subsequently inflated confidence. In this experiment, we examined students' perceptions of immediate and inflated confidence and whether their reliance on confidence varies as a function of the explanations given by the eyewitness for her inflated confidence. Each of 126 university students viewed one of five versions of a videotaped officer–eyewitness interaction depicting an eyewitness identification and follow‐up interview in which the eyewitness gave a (1) high or (2) moderate level of confidence or inflated her confidence and gave a (3) confidence epiphany, (4) memory contamination, or (5) no explanation for the inflation. The memory contamination and confidence epiphany explanations led to lower ratings of identification accuracy as compared to the high‐confidence control condition, supporting the immediate confidence recommendation but in some ways contradicting previous research on this issue. The results suggest the need for further research to understand the conditions under which confidence inflation influences juror evaluations of eyewitness identification.     

Expert testimony about eyewitness identification

Recent research concerning eyewitness identification is surveyed with respect to its adequacy (reliability and validity) to support expert testimony. The conclusion is that the scientific basis is generally inadequate and that the more we have learned about various aspects of eyewitness identification, the most inadequate it appears. The argument is made that presentation in policy settings requires greater circumspection than would be required in presentation to scientific audiences. Prudential rules are suggested. They would have the effect of sharply reducing participation in the adversarial system.     

Uses and abuses of eyewitness identification confidence

When attempting to identify an offender whom they saw commit a crime, eyewitnesses are frequently asked to indicate their confidence in their memories. Confidence judgments may be expressed prior to seeing a line‐up, after making an identification decision or in the courtroom. Such judgments can exert an important influence on decision making within the criminal justice system. Here, I examine theory and evidence that bear on the likely usefulness of such confidence judgments for diagnosing the accuracy of the associated identification. Contrary to often expressed views, I argue that confidence recorded immediately after the identification test is informative about the identity of the offender. Confidence expressions obtained at other times are likely to be misleading. Important directions for future confidence research are identified.     

Juror sensitivity to eyewitness identification evidence

A mock-jury study was conducted to examine juror sensitivity to eyewitness identification evidence. Subjects were 129 eligible and experienced jurors from Dane County, Wisconsin, who viewed a videotaped trial that involved an eyewitness identification. Ten factors associated with the crime and the identification (e.g., disguise of the perpetrator, retention interval, confidence of the witness) were manipulated. The results of this mock-jury study were combined with those of a previous study using the same experimental stimuli and procedures, but using undergraduates as subjects. This analysis showed that the confidence of the eyewitness was the most powerful predictor of verdicts (p<.05) and that differences between undergraduates and eligible jurors in their sensitivity to eyewitness evidence were negligible.     

Children's and adults' eyewitness identification accuracy when a culprit changes his appearance: Comparing simultaneous and elimination lineup procedures

Adults' (N = 239) and children's (N = 177, age range 8–13 years) identification abilities were examined when a culprit underwent a change in appearance following the commission of a crime. Simultaneous and elimination lineup procedures were compared to determine the reliability of each under ‘change in appearance’ conditions. Participants viewed a staged, videotaped theft and then examined a target‐present or ‐absent lineup. Correct identifications (target‐present lineups) decreased following a change in appearance regardless of age of witness and lineup procedure. Children's correct rejection rates (target‐absent lineups) were lower than those of adults. The elimination procedure compared with the simultaneous procedure was more effective at increasing correct rejections when the lineup members matched the culprit's appearance for children and adults. When lineup members did not match the culprit's appearance, correct rejection rates were similar across the two identification procedures for both aged groups.     

Change blindness can cause mistaken eyewitness identification

The current study investigated the effects of change blindness and crime severity on eyewitness identification accuracy. This research, involving 717 subjects, examined change blindness during a simulated criminal act and its effects on subjects' accuracy for identifying the perpetrator in a photospread. Subjects who viewed videos designed to induce change blindness were more likely to falsely identify the innocent actor relative to those who viewed control videos. Crime severity did not influence detection of change; however, it did have an effect on eyewitness accuracy. Subjects who viewed a more severe crime ($500 theft) made fewer errors in perpetrator identification than those who viewed a less severe crime ($5 theft). This research has theoretical implications for our understanding of change blindness and practical implications for the real‐world problem of faulty eyewitness testimony.     

Juror decision making in eyewitness identification cases

The lay-person's knowledge of the factors that influence eyewitness memory was examined by evaluating the manner in which mock jurors integrated eyewitness evidence to draw inferences about defendant culpability and the likelihood that an identification was correct. Three hundred and twenty-one undergraduates viewed a videotaped trial within which ten witness and identification factors were manipulated between trials. Manipulation checks showed that subjects demonstrated superior memory for the evidence and the manipulated variables had their intended impact on appropriate rating scales. However, only one variable, witness confidence, had reliable effects on subjects' perceptions of culpability, on the perceived likelihood that the identification was correct, and on several other relevant dependent variables. Eight variables that have been shown to affect identification accuracy in the empirical literature had trivial effects on mock jurors' inferences. It was concluded that lay-people are insensitive to the factors that influence eyewitness memory.     

Influence of expert testimony regarding eyewitness accuracy on jury decisions

To determine the influence of expert testimony regarding the general unreliability of eyewitnesses, a two-phase study was conducted. In the first phase, 24 community residents served as jurors on four six-person juries. A burglary case was tried in 120 District Court. El Paso, Texas. Two juries heard all the evidence including the expert testimony of a psychologist and the other two heard all of the testimony except that of the psychologist. During the second phase, 24 student jurors constituting four six-person juries viewed a videotape of the trial. Two of these juries saw the entire proceeding from the first phase including the expert testimony and the remaining two saw all but the expert testimony. All juries acquitted the defendant; however, those who heard the expert testimony significantly lowered their judgments of the accuracy and reliability of eyewitness identification as well as its overall importance to the trial. Further, those juries that heard the expert testimony spent a significantly longer time discussing eyewitness identification as well as other relevant evidence. No differences between community residents and college student juries were obtained.The authors wish to thank Judge Brunson Moore, Mr. David Jeans, Mr. Ricky Glenn Smith, Detective James Christianson, D. Steven Cooper, Rachel Hanna, Daniel Torres, and Patricia Tetreault. All of these people participated in the trial and without them this research could not have been conducted. This research was supported by Gift Funds of the Department of Psychology, University of Texas at El Paso.     

Courtroom testimony by psychologists on eyewitness identification issues

This article makes two major points in regard to expert psychological testimony on eyewitness identification. First, the attention devoted by psychologists to eyewitness identification issues is far out of proportion to the incidence of trials involving eyewitness identifications of criminal defendants; furthermore, the often-expressed concern over wrongful convictions is probably misplaced. Second, the experimental methods used in studies of eyewitness performance are fundamentally unsuited for drawing conclusions about actual witnesses. Hence, there is not an adequate scientific foundation for expert psychological testimony on eyewitness identification. Archival research is perhaps the most promising approach to the study of the criminal justice system.