Eyewitness Performance Research Articles

Mock jurors’ evaluations of eyewitness identification evidence based on appearance change and associated instructions

ABSTRACT It is common for a perpetrator’s appearance to change between committing the crime and later appearing in an identification procedure. The present study investigated how such appearance change (AC) would be evaluated by potential jurors, as well as tested mock jurors’ evaluations of the appearance change instruction (ACI) utilized by police. Recent research indicates that the ACI harms eyewitness identification accuracy and limits the predictive nature of confidence, but would mock jurors’ estimates of suspect guilt reflect this? In Experiment 1, AC reduced suspect guilt estimates, but the ACI eliminated this effect, indicating that potential jurors may not discount an identification if made after ACI. Experiment 2 introduced a hypothetical eyewitness expert who informs participants about the research that both AC and the ACI harm eyewitness performance. We also compared two types of expert instructions based on recent mock jury research: simple versus reason-based. Both types served to reduce suspect guilt estimates associated with AC. Participants still trusted the ACI even with expert instructions, but not as much as when there was no expert. Lastly, we also manipulated eyewitness confidence level, supporting recent research that manipulations have no effect on suspect guilt estimates when confidence is low (i.e. uncertainty trumps).

Double misinformation and eyewitness performance: An experimental replication

AbstractEyewitnesses may be exposed to multiple pieces of misinformation concerning the same original detail. The two misleading details contradicting each other enable detecting a discrepancy between them, which, given that only one of them can be true, should reduce credibility of the misinformation source(s) and improve reporting. This, however, can only happen at sufficiently high levels of misinformation availability (i.e., encoding of misinformation and its subsequent accessibility): with low misinformation availability, double misinformation should instead increase the misinformation effect, providing multiple chances of yielding to misinformation. To test these predictions, we experimentally manipulated misinformation availability (high vs. low) and presented double or single misinformation. However, double versus single misinformation presentation did not affect performance or interact with misinformation availability and participants frequently reported misinformation while fully detecting discrepancies between items. Therefore, discrepancy detection alone may not be sufficient in reducing the misinformation effect, with various decision‐making processes involved in reporting.

How to measure lineup fairness: concurrent and predictive validity of lineup-fairness measures

ABSTRACT The current study examined the concurrent and predictive validity of four families of lineup-fairness measures – mock-witness measures, perceptual ratings, face-similarity algorithms, and resultant assessments (assessments based on eyewitness participants’ responses) – with 40 mock crime/lineup sets. A correlation analysis demonstrated weak or non-significant correlations between the mock-witness measures and the algorithms, but the perceptual ratings correlated significantly with both the mock-witness measures and the algorithms. These findings may reflect different task characteristics – pairwise similarity ratings of two faces versus overall similarity ratings for multiple faces – and suggest how to use algorithms in future eyewitness research. The resultant assessments did not correlate with the other families, but a multilevel analysis showed that only the resultant assessments – which are based on actual eyewitness choices – predicted eyewitness performance reliably. Lineup fairness, as measured using actual eyewitnesses, differs from lineup fairness as measured using the three other approaches.

Evaluating the impact of first-yes-counts instructions on eyewitness performance using the two-high threshold eyewitness identification model

In eyewitness research, multiple identification decisions in sequential lineups are typically prevented by telling participants that only their first identification decision counts. These first-yes-counts instructions are incompatible with standard police protocols prescribing that witnesses shall see the entire lineup. Horry et al. were the first to experimentally test how this discrepancy between eyewitness research and standard police protocols affects eyewitness identification decisions. Here, the two-high threshold eyewitness identification model was used to disentangle the effect of the first-yes-counts instructions on the detection and guessing processes underlying eyewitness identification decisions. We report both a reanalysis of Horry et al.’s data and a conceptual replication. Both the reanalysis and the results of the conceptual replication confirm that first-yes-counts instructions do not affect the detection of the culprit but decrease the probability of guessing-based selections. To improve the ecological validity, research on sequential lineups should avoid first-yes-counts instructions.

Non-linear effects of stress on eyewitness memory

The effect of stress on face identification is not yet clear, with recent experiments finding positive, negative and null results. Here we report the results of two experiments examining the effect of stress on eyewitness performance in line-up face recognition tasks. Both experiments use a stress manipulation and live mock crime paradigm to examine the relationship between stress at encoding and subsequent line-up performance. Experiment 1 replicated an experiment by Sauerland et al. (Behav Sci Law. 2016;34(4):580–594) which induced stress using the Maastricht Acute Stress Test. The replication found the same null result as the original experiment. Experiment 2 aimed to address a limitation of many laboratory experiments which dichotomise stress into low and high groups for comparison. As the Yerkes-Dodson law (1908) suggests that a non-linear relationship exists between stress and performance, it was hypothesised that using a low, medium and high stress manipulation might show clearer results than a dichotomous paradigm. The results of Experiment 2 show a non-linear relationship, with no difference between the low and high stress groups but better performance by the middle stress group. The results suggest that a different approach is required in experiments on stress and face recognition, as the stress–performance relationship is likely non-linear. Significance: Non-linear models are better predictors of face recognition in line-up tasks than are linear models. Two group designs provide insufficient resolution to capture the stress–performance relationship.

A stronger memory for the perpetrator may attenuate effects of the identification procedure on eyewitness accuracy

AbstractThe identification procedure can greatly affect eyewitness performance, but this may be contingent upon a relatively weak memory for the perpetrator. In a large preregistered experiment (N = 13,728), we manipulated memory strength and tested participants with a target‐present or ‐absent showup or lineup (size 3 or 6). All fillers were description‐matched but were of low or high similarity with the target. We replicated the advantage of fair simultaneous lineups over showups and the advantage of low‐ over high‐similarity fillers when memory for the perpetrator's face was weaker (short exposure duration), but both effects were significantly reduced when memory was stronger. There was no effect of lineup size regardless of memory strength or filler similarity. We conclude that some recommendations to police may be more robust than others across changes in estimator variables such as memory strength and that more research is needed on interactions between estimator and system variables.

Comparing witness performance in the field versus the lab: How real-world conditions affect eyewitness decision-making.

This field-simulation experiment was designed to compare eyewitness performance when conducting show ups and lineups under field versus laboratory conditions. We expected to replicate the findings from previous field-simulation experiments showing overconfidence in show up identifications made under field but not lab conditions, and further predicted that under field conditions, high-confidence identifications are more likely to be correct when using lineups compared with show ups. It was also expected that field conditions would lead witnesses to lower their criterion for choosing with show ups, but we did not know how field conditions would affect lineup decision-making. Participants (N = 719) witnessed the theft of a laptop computer and were asked to identify a suspect from a live show up, a photographic show up, or a photographic lineup administered under either field or lab conditions. In the field condition, uniformed officers functioned as experimenters and participants were immersed in what they were led to believe was an actual police investigation. In the lab condition, participants were debriefed before the identification procedure that the theft was staged for research purposes and that their identifications were being made as part of a study on eyewitness memory. As predicted, witnesses were overconfident in their show up identifications made under field but not lab conditions, and high-confidence identifications were more likely to be correct when using lineups compared with show ups. Also as expected, field conditions led witnesses to lower their criterion for choosing with show ups regardless of culprit presence. However, the opposite was true for lineups, such that field conditions resulted in witnesses raising their criterion for choosing. Field conditions had a very different effect on witness performance when conducting show ups compared with lineups. When witnesses were led to believe that their identification would result in the arrest and prosecution of the suspect, they became more liberal in their decision-making when show ups were used but more conservative when lineups were employed. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Validity of mock-witness measures for assessing lineup fairness

ABSTRACT Although eyewitness researchers have used mock-witness measures to assess aspects of lineup fairness, they have paid little attention to their validity. The current study tested predictive validity, convergent validity, and discriminant validity of mock-witness measures from a meta-analytic perspective. Overall, mock-witness measures had predictive validity, particularly in target-absent (TA) lineups – the lineup fairness estimated by the measures reliably predicted eyewitnesses’ choosing behaviors and discriminability of a suspect from fillers in TA lineups. However, correlations between lineup fairness estimated by mock-witnesses and eyewitness performance were significant in target-present (TP) lineups only when eyewitnesses had a moderate memory for the perpetrator. Multitrait-multimethod correlations demonstrated significant intradomain correlations between mock-witness measures and other lineup fairness indices and nonsignificant interdomain correlations between the mock-witness measures and indices reflecting memory strength for the perpetrator, which supported convergent validity and discriminant validity, respectively. The implications for research and practice are discussed.

The Law and Science of Eyewitness Evidence

Eyewitness evidence, used in tens of thousands of criminal cases each year, crucially depends on eyewitness memory, which is quite fallible. The potential inaccuracy of eyewitness memory has been long demonstrated by examples of mis-identifications, including in cases of wrongful conviction. Eyewitness identification procedures, which are themselves experiments, lend themselves to scientific research as do few others in law. Today, decades of scientific research on visual perception and memory have identified key causes of error and methods for improving eyewitness performance. As a result, eyewitness evidence has become a testing ground for the use of science to inform the law. This Article examines how legal actors — state and federal courts, state lawmakers, and police agencies — have responded to this body of research. While U.S. Supreme Court rulings set a constitutional floor, we find that it largely does not inform eyewitness evidence law. State courts have increasingly incorporated eyewitness memory science, as we describe in a detailed fifty-state survey of rulings. Second, we explore how state lawmakers have done still more, in an analysis of twenty-four state statutes that regulate eyewitness identification procedure. Third, policing agencies have most eagerly embraced revised identification practices to take account of scientific research. We describe a sea change in police practice, including through model policy adopted in twenty-nine states. Based on these findings, we call into question top-down, stare-decisis-bound, and federal court-centric accounts that dominate constitutional criminal procedure. Further, we describe how research continues to progress; a new generation of research promises to further improve accuracy of eyewitness procedures. While constitutional criminal procedure is unlikely to change in the near future, we expect that local actors will harness research developments. We conclude by asking why, in the eyewitness area, criminal investigation and procedure have been so receptive to research. We suggest that rather than adopting a legal precedent-based system, police practices and statutes employ a scientific framework that can incorporate new discoveries. This account of dissemination and adoption of research points towards a dynamic framework for the use of science in the legal system.

A perceptual scaling approach to eyewitness identification

Eyewitness misidentification accounts for 70% of verified erroneous convictions. To address this alarming phenomenon, research has focused on factors that influence likelihood of correct identification, such as the manner in which a lineup is conducted. Traditional lineups rely on overt eyewitness responses that confound two covert factors: strength of recognition memory and the criterion for deciding what memory strength is sufficient for identification. Here we describe a lineup that permits estimation of memory strength independent of decision criterion. Our procedure employs powerful techniques developed in studies of perception and memory: perceptual scaling and signal detection analysis. Using these tools, we scale memory strengths elicited by lineup faces, and quantify performance of a binary classifier tasked with distinguishing perpetrator from innocent suspect. This approach reveals structure of memory inaccessible using traditional lineups and renders accurate identifications uninfluenced by decision bias. The approach furthermore yields a quantitative index of individual eyewitness performance.

Recruiting Eyewitness Science in Criminal Investigations: The Pocket Man Case

ABSTRACTDo surveillance shots and phantom drawings of the perpetrator in child abuse cases, images that are widely published in public media, contaminate the identifications made by young victims? This question was raised in the later phases of the investigations into a Norwegian child abuse case that involved a large number of victims, where a suspect was apprehended, and a photo lineup with the victims was planned. The police sought to answer the question by conducting a simple experiment: Two samples of participants – children in the age range of the real victims but from a different part of the country, and police cadets – were presented with the published photographs and drawings of the suspect; after a short interval, they were asked to pick the man they had seen in a 12-person photo lineup that was planned to be used with the real victims. The results showed that media exposure – surveillance shots and phantom drawings – in this case did not increase the probability of selecting the suspect. It is concluded that criminal investigations in some cases may profit from research evaluations of police procedures and eyewitness performance, supporting the investigative process by sorting out unreliable procedures and increasing the quality of the evidence.

Mental Reinstatement of Context: Do individual differences in mental time travel and eyewitness occupation influence eyewitness performance over different delay intervals?

AbstractThe Cognitive Interview is a memory‐enhancing interview protocol designed to optimise the access and retrieval of eyewitness memories. Its Mental Reinstatement of Context (MRC) component requires interviewees to mentally reconstruct the crime event they witnessed. Individual differences in mental time travel (MTT) relate to the extent to which a person mentally re‐experiences personal events from his or her past. Individual differences in MTT have been found to predict correct recall of a simulated crime event under immediate MRC recall conditions. To explore the relationship between MTT and performance under MRC conditions further, the present study presented a simulated crime video to 30 police officers and 26 members of the public. Eyewitness recall was tested under MRC conditions either immediately or 1 week later. Participants' general MTT and also MTT relating specifically to the crime video itself were measured via self‐report. Less correct information and more confabulations were produced after 1 week, but delay had no effect on the amount of incorrect information reported. No difference in recall was found between police officers and members of the public. Better quality MTT relating to the crime video was found to be a positive predictor of the amount of information correctly recalled under immediate conditions but not after 1 week. General MTT scores did not predict correct recall under either delay condition. Interviewers need to be aware that, due to individual differences, some witnesses may perform better under the MRC component than others.

Supplemental Material for New Signal Detection Theory-Based Framework for Eyewitness Performance in Lineups

Supplemental Material for New Signal Detection Theory-Based Framework for Eyewitness Performance in Lineups

A preliminary investigation on the performance of brain-injured witnesses on target-absent line-up procedures

The current study was a preliminary investigation that aimed to compare the performance of eyewitnesses with and without a brain injury on two target-absent line-up procedures: a simultaneous procedure and a sequential procedure with confidence ratings. A 2 × 2 design (N = 25) was employed, where both brain-injured (n = 15) and non-brain-injured (n = 10) participants were shown a short video of a non-violent crime taking place before taking part in either a simultaneous or sequential target-absent line-up. Participants’ general cognitive abilities and memory recall accuracy were also measured. Results found no significant differences in false identification rates between brain-injured and non-brain-injured witnesses. It was also found that participants with a greater memory accuracy were in fact more likely to make a false identification. The implications and limitations of the study are discussed.

Do measures of memory, language, and attention predict eyewitness memory in children with and without autism?

Background and aimsThere are few investigations of the relationship between cognitive abilities (memory, language, and attention) and children’s eyewitness performance in typically developing children, and even fewer in children on the autism spectrum. Such investigations are important to identify key cognitive processes underlying eyewitness recall, and assess how predictive such measures are compared to intelligence, diagnostic group status (autism or typically developing) and age. MethodsA total of 272 children (162 boys, 110 girls) of age 76 months to 142 months (M = 105 months) took part in this investigation: 71 children with autism and 201 children with typical development. The children saw a staged event involving a minor mock crime and were asked about what they had witnessed in an immediate Brief Interview. This focused on free recall, included a small number of open-ended questions, and was designed to resemble an initial evidence gathering statement taken by police officers arriving at a crime scene. Children were also given standardised tests of intelligence, memory, language, and attention. Results & conclusionsDespite the autism group recalling significantly fewer items of correct information than the typically developing group at Brief Interview, both groups were equally accurate in their recall: 89% of details recalled by the typically developing group and 87% of the details recalled by the autism group were correct. To explore the relationship between Brief Interview performance and the cognitive variables, alongside age, diagnostic group status and non-verbal intelligence quotient, multiple hierarchical regression analyses were conducted, with Brief Interview performance as the dependant variable. Age and diagnostic group status were significant predictors of correct recall, whereas non-verbal intelligence was less important. After age, non-verbal intelligence, and diagnostic group status had been accounted for, the only cognitive variables that were significant predictors of Brief Interview performance were measures of memory (specifically, memory for faces and memory for stories). There was little evidence of there being differences between the autism and typically developing groups in the way the cognitive variables predicted the Brief Interview. ImplicationsThe findings provide reassurance that age – the most straightforward information to which all relevant criminal justice professionals have access – provides a helpful indication of eyewitness performance. The accuracy of prediction can be improved by knowing the child’s diagnostic status (i.e. whether the child is on the autism spectrum), and further still by using more specific assessments (namely memory for faces and memory for stories), possibly via the input of a trained professional. Importantly, the findings also confirm that whilst children with autism may recall less information than typically developing children, the information they do recall is just as accurate.

Mental time travel ability and the Mental Reinstatement of Context for crime witnesses.

Mental time travel ability marks how well the phenomenological aspects of events are mentally re-experienced during recall. The Cognitive Interview (CI) elicits eyewitness information. One of its techniques, Mental Reinstatement of Context (MRC), asks eyewitnesses to reinstate the incident's context mentally before recall. Fifty-six participants watched a simulated crime video. Self-report measures were then taken to estimate general mental time travel ability. Participants were questioned subsequently about the video. Eyewitness performance under MRC was compared with the CI's Report Everything (RE) technique, wherein eyewitnesses recall everything they can but with no invitation to mentally reinstate the context. There was no effect of interview condition on accuracy of recall; however, general mental time travel ability was positively associated with the amount of correct and incorrect information produced under MRC, but not RE, conditions. This is the first empirical demonstration that MRC instructions engage the mental time travel capacities they purport to.

The Thin Blue Line-Up: Comparing Eyewitness Performance by Police and Civilians

Police officers are often believed to provide more reliable testimony than civilian eyewitnesses. We reviewed the available empirical evidence for this belief. There is some evidence to suggest that police officers do indeed report more accurate details about witnessed events than civilians do, particularly concerning crime-relevant details. That research finding does not translate directly to practice, however, since an average difference between police and civilian witnesses does not mean that a particular police officer in a specific case should be believed over a particular civilian eyewitness. More importantly, police officers are no better than civilians at identifying a perpetrator from a line-up and may even be more likely to make a false identification. Because eyewitness misidentifications have far more severe consequences than misreported event details, expert witnesses in court should warn decision-makers that police officers are at least as likely as the average eyewitness to falsely identify an innocent person.

Valence, implicated actor, and children's acquiescence to false suggestions

Although adverse effects of suggestive interviewing on children's accuracy are well documented, it remains unclear as to whether these effects vary depending on the valence of and the actor implicated in suggestions. In this study, 124 3-8-year-olds participated in a classroom activity and were later questioned about positive and negative false details. The interviewer provided positive reinforcement when children acquiesced to suggestions and negative feedback when they did not. Following reinforcement or feedback, young children were comparably suggestible for positive and negative details. With age, resistance to suggestions about negative details emerged first, followed by resistance to suggestions about positive details. Across age, more negative feedback was required to induce acquiescence to negative than positive false details. Finally, children were less willing to acquiesce when they (versus the confederate) were implicated. Findings highlight the interactive effects of valence and children's age on their eyewitness performance in suggestive contexts.

Consistency across repeated eyewitness interviews: contrasting police detectives' beliefs with actual eyewitness performance.

In the legal system, inconsistencies in eyewitness accounts are often used to discredit witnesses’ credibility. This is at odds with research findings showing that witnesses frequently report reminiscent details (details previously unrecalled) at an accuracy rate that is nearly as high as for consistently recalled information. The present study sought to put the validity of beliefs about recall consistency to a test by directly comparing them with actual memory performance in two recall attempts. All participants watched a film of a staged theft. Subsequently, the memory group (N = 84) provided one statement immediately after the film (either with the Self-Administered Interview or free recall) and one after a one-week delay. The estimation group (N = 81) consisting of experienced police detectives estimated the recall performance of the memory group. The results showed that actual recall performance was consistently underestimated. Also, a sharp decline of memory performance between recall attempts was assumed by the estimation group whereas actual accuracy remained stable. While reminiscent details were almost as accurate as consistent details, they were estimated to be much less accurate than consistent information and as inaccurate as direct contradictions. The police detectives expressed a great concern that reminiscence was the result of suggestive external influences. In conclusion, it seems that experienced police detectives hold many implicit beliefs about recall consistency that do not correspond with actual recall performance. Recommendations for police trainings are provided. These aim at fostering a differentiated view on eyewitness performance and the inclusion of more comprehensive classes on human memory structure.

Double-blind photo lineups using actual eyewitnesses: an experimental test of a sequential versus simultaneous lineup procedure.

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.