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Eyewitness identifications based on biased or unbiased line-up instructions after a realistic and violent hostage simulation

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Abstract

Few earlier studies have investigated the effects of highly stressful, realistic, violent, and threatening scenarios on eyewitness identification accuracy in an ecologically valid setting. The majority of studies have relied on laboratory-based simulated (videos/images) experiments. The present study investigated line-up accuracy approximately 1 week after a hostage simulation event. We administered biased line-up instructions to 50% of participants to investigate how this impacted choosing behaviour and accuracy. Based on 1030 line-up decisions (N = 122), we found that average accuracy was 38% in target present (TP) and 54% in target absent (TA) line-ups and that biased line-up instructions decreased overall accuracy (vs. unbiased). The hit rate for TP line-ups with biased instructions was 0.43 (unbiased instructions: 0.33), while the false alarm rate for TA line-ups with biased instructions was 0.60 (unbiased instructions: 0.32). We found that high confidence was associated with correct identifications and that shorter response times were indicative of correct rejections. Our findings demonstrate, in a more realistic scenario than the majority of eyewitness identification studies, the effect that biased line-up instructions lead to increased choosing and decreased accuracy.

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According to the Diagnostic Feature‐Detection (DFD) hypothesis, the presence of fillers that match the eyewitness's description of the perpetrator will boost discriminability beyond a showup, and very few fillers may suffice to produce the advantage. We tested this hypothesis by comparing showups with simultaneous lineups of size 3, 6, 9, and 12. Participants (N = 10,433) were randomly assigned to one of these conditions, as well as target‐present (TP) versus target‐absent (TA) lineup. As predicted by the DFD hypothesis, lineups were superior to showups, and there was no advantage with increased lineup size beyond a 3‐member lineup. The confidence‐accuracy (CA) relationship held a similar pattern. The only effect of increased lineup size was a lower likelihood of choosing a suspect (guilty or innocent). We conclude that police should focus more on the quality rather than quantity of fillers. This article is protected by copyright. All rights reserved.
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Objective: The Executive Committee of the American Psychology-Law Society (Division 41 of the American Psychological Association) appointed a subcommittee to update the influential 1998 scientific review paper on guidelines for eyewitness identification procedures. Method: This was a collaborative effort by six senior eyewitness researchers, who all participated in the writing process. Feedback from members of AP-LS and the legal communities was solicited over an 18-month period. Results: The results yielded nine recommendations for planning, designing, and conducting eyewitness identification procedures. Four of the recommendations were from the 1998 article and concerned the selection of lineup fillers, prelineup instructions to witnesses, the use of double-blind procedures, and collection of a confidence statement. The additional five recommendations concern the need for law enforcement to conduct a prelineup interview of the witness, the need for evidence-based suspicion before conducting an identification procedure, video-recording of the entire procedure, avoiding repeated identification attempts with the same witness and same suspect, and avoiding the use of showups when possible and improving how showups are conducted when they are necessary. Conclusions: The reliability and integrity of eyewitness identification evidence is highly dependent on the procedures used by law enforcement for collecting and preserving the eyewitness evidence. These nine recommendations can advance the reliability and integrity of the evidence. (PsycINFO Database Record (c) 2020 APA, all rights reserved).
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It is generally agreed that proper pre‐lineup instructions can reduce the rate of mistaken identifications of innocent suspects. However, the exact nature of these instructions have not been empirically established. We compared the effects of the detailed pre‐lineup instructions recommended by the U.S. Department of Justice to a simple instruction that the perpetrator may or may not be present. Both forms of unbiased instructions significantly reduced mistaken identifications when compared to biased instructions. Comparison of performance using the utility‐based analysis deviation from perfect performance demonstrated that unbiased instructions are to be preferred under assumptions of low base rates or high costs of mistaken identifications and do as well as biased instructions under assumptions of high base rates or low cost of misidentification. This article is protected by copyright. All rights reserved.
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Increased distance between an eyewitness and a culprit decreases the accuracy of eyewitness identifications, but the maximum distance at which reliable observations can still be made is unknown. Our aim was to identify this threshold. We hypothesized that increased distance would decrease identification, rejection accuracy, confidence and would increase response time. We expected an interaction effect, where increased distance would more negatively affect younger and older participants (vs. young adults), resulting in age-group specific distance thresholds where diagnosticity would be 1. We presented participants with 4 live targets at distances between 5 m and 110 m using an 8-person computerized line-up task. We used simultaneous and sequential target-absent or target-present line-ups and presented these to 1,588 participants (age range = 6-77; 61% female; 95% Finns), resulting in 6,233 responses. We found that at 40 m diagnosticity was 50% lower than at 5 m and with increased distance diagnosticity tapered off until it was 1 (±0.5) at 100 m for all age groups and line-up types. However, young children (age range = 6-11) and older adults (age range = 45-77) reached a diagnosticity of 1 at shorter distances compared with older children (age range = 12-17) and young adults (age range = 18-44). We found that confidence dropped with increased distance, response time remained stable, and high confidence and shorter response times were associated with identification accuracy up to 40 m. We conclude that age and line-up type moderate the effect distance has on eyewitness accuracy and that there are perceptual distance thresholds at which an eyewitness can no longer reliably encode and later identify a culprit. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
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The present article focuses on a utility-based understanding of criminal justice practice regarding eyewitness identifications. We argue that there are 4 distinct types of utility that should be considered when evaluating an identification procedure. These include the utility associated with all identifications, the utility associated with only the high confidence identifications, the average utility across the full range of identifications, and the maximum utility that can be attained by selecting an ideal criterion. We show that in almost all cases in which the difference between 2 procedures is defined by a tradeoff between increased guilty suspect IDs and increased innocent suspect IDs, current ROC (receiver operating characteristic) curve approaches fail to provide unambiguous information about which eyewitness identification procedures are best in practice. We introduce a novel graphical technique called utility difference curves that illustrates the impact that differential assumptions about base rates and cost structures have on the likely benefits of different identification procedures. The research emphasizes the importance of considering assumptions about base rates and costs associated with different types of eyewitness errors. We also clarify situations in which the outcome of eyewitness experiments are unambiguous and those in which careful consideration of tradeoffs are necessary.
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General Audience Summary A primary concern in eyewitness identification research is determining which of two lineup procedures leads to better applied outcomes. The difficulty in making this determination is that the procedure that leads to more culprit identifications (a benefit) also normally leads to more innocent-suspect identifications (a cost). This pattern of results is sometimes referred to as a trade-off, reflecting the fact that each of the two procedures comes with both a cost and a benefit. When the difference between two procedures is defined by a trade-off, sophisticated analyses are required to determine which lineup procedure is superior. In many scientific domains, Receiver Operator Characteristic (ROC) is used for analyzing trade-off problems and it was recently argued that ROC analysis could be used to analyze trade-off problems in the eyewitness lineup literature (Wixted & Mickes 2012). In more recent research, we found that when the difference between two lineup procedures is defined by a trade-off, ROC analysis does not inform on which of two lineup procedures leads to better applied outcomes (Lampinen, Smith, & Wells, 2018). More precisely, for problems defined by a trade-off ROC analysis will sometimes favor the inferior lineup procedure. In this paper, we introduce a novel ROC-based measure – deviation from perfect performance (DPP) – for comparing eyewitness lineup procedures. Contrary to traditional ROC-based measures, DPP consistently favors the lineup procedure that leads to better applied outcomes. Our findings suggest that DPP will lead to more reliable conclusions about which of two lineup procedures leads to better applied outcomes.
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In the eyewitness identification literature, stress and arousal at the time of encoding are considered to adversely influence identification performance. This assumption is in contrast with findings from the neurobiology field of learning and memory, showing that stress and stress hormones are critically involved in forming enduring memories. This discrepancy may be related to methodological differences between the two fields of research, such as the tendency for immediate testing or the use of very short (1-2 hours) retention intervals in eyewitness research, while neurobiology studies insert at least 24 hours. Other differences refer to the extent to which stress-responsive systems (i.e., the hypothalamic-pituitary-adrenal axis) are stimulated effectively under laboratory conditions. The aim of the current study was to conduct an experiment that accounts for the contemporary state of knowledge in both fields. In all, 123 participants witnessed a live staged theft while being exposed to a laboratory stressor that reliably elicits autonomic and glucocorticoid stress responses or while performing a control task. Salivary cortisol levels were measured to control for the effectiveness of the stress induction. One week later, participants attempted to identify the thief from target-present and target-absent line-ups. According to regression and receiver operating characteristic analyses, stress did not have robust detrimental effects on identification performance. Copyright © 2016 John Wiley & Sons, Ltd.
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Significance Diverse cognitive abilities have typically been found to intercorrelate highly and to be strongly influenced by genetics. Recent twin studies have suggested that the ability to recognize human faces is an exception: it is similarly highly heritable, but largely uncorrelated with other abilities. However, assessing genetic relationships—the degree to which traits are influenced by the same genes—requires very large samples, which have not previously been available. This study, using data from more than 2,000 twins, shows for the first time, to our knowledge, that the genetic influences on face recognition are almost entirely unique. This finding provides strong support for the view that face recognition is “special” and may ultimately illuminate the nature of cognitive abilities in general.
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Weapon focus is frequently cited as a factor in eyewitness testimony, and is broadly defined as a weapon-related decrease in performance on subsequent tests of memory for those elements of an event or visual scene concurrent to the weapon. This effect has been attributed to either (a) physiological or emotional arousal that narrows the attentional beam (arousal/threat hypothesis), or (b) the cognitive demands inherent in processing an unusual object (e.g. weapon) that is incongruent with the schema representing the visual scene (unusual item hypothesis). Meta-analytical techniques were applied to test these theories as well as to evaluate the prospect of weapon focus in real-world criminal investigations. Our findings indicated an effect of weapon presence overall (g = 0.53) that was significantly influenced by retention interval, exposure duration, and threat but unaffected by whether the event occurred in a laboratory, simulation, or real- world environment.
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The current article reviews the own-race bias (ORB) phenomenon in memory for human faces, the finding that own-race faces are better remembered when compared with memory for faces of another, less familiar race. Data were analyzed from 39 research articles, involving 91 independent samples and nearly 5,000 participants. Measures of hit and false alarm rates, and aggregate measures of discrimination accuracy and response criterion were examined, including an analysis of 8 study moderators. Several theoretical relationships were also assessed (i.e., the influence of racial attitudes and interracial contact). Overall, results indicated a "mirror effect" pattern in which own-race faces yielded a higher proportion of hits and a lower proportion of false alarms compared with other-race faces. Consistent with this effect, a significant ORB was also found in aggregate measures of discrimination accuracy and response criterion. The influence of perceptual learning and differentiation processes in the ORB are discussed, in addition to the practical implications of this phenomenon. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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Proposes a distinction between 2 types of applied eyewitness-testimony research: System-variable (SV) research investigates varibles that are manipulable in actual criminal cases (e.g., the structure of a lineup) and, thus, has the potential for reducing the inaccuracies of eyewitnesses; estimator-variable (EV) research, however, investigates variables that cannot be controlled in actual criminal cases (e.g., characteristics of the witness) and, thus, can only be used in the courtroom to augment or discount the credibility of eyewitnesses. SVs and EVs are contrasted with respect to their relative potential for positive contribution to criminal justice, and it is concluded that SV research may prove more fruitful than EV research. It is also argued that several methodological biases may be exacerbating the rate of misidentifications in staged-crime paradigms. (33 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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Past research has considered the impact of biased police lineup instructions upon eyewitness lineup performance. Biased instructions either suggest to the eyewitness that the perpetrator is in the lineup or otherwise discourage a no choice response. A meta-analysis of 18 studies was employed to review the hypothesis that biased instructions lead to greater willingness to choose and less accurate lineup identifications than do unbiased instructions. The role of moderating variables in the instruction procedure was also considered. In support of the hypothesis, a significantly higher level of choosing followed biased instructions. Lineup type moderated performance accuracy, however. For target-absent lineups the increased level of choosing following biased instructions resulted in reduced identification accuracy. Biased instructions within a target-present lineup generated a higher level of confidence, but had minimal impact on accuracy. Implications for police practice are discussed.
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Face recognition is impaired when changes are made to external face features (e.g., hairstyle), even when all internal features (i.e., eyes, nose, mouth) remain the same. Eye movement monitoring was used to determine the extent to which altered hairstyles affect processing of face features, thereby shedding light on how internal and external features are stored in memory. Participants studied a series of faces, followed by a recognition test in which novel, repeated, and manipulated (altered hairstyle) faces were presented. Recognition was higher for repeated than manipulated faces. Although eye movement patterns distinguished repeated from novel faces, viewing of manipulated faces was similar to that of novel faces. Internal and external features may be stored together as one unit in memory; consequently, changing even a single feature alters processing of the other features and disrupts recognition.
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Recent research using a calibration approach indicates that eyewitness confidence assessments obtained immediately after a positive identification decision provide a useful guide as to the likely accuracy of the identification. This study extended research on the boundary conditions of the confidence–accuracy (CA) relationship by varying the retention interval between encoding and identification test. Participants (N = 1,063) viewed one of five different targets in a community setting and attempted an identification from an 8-person target-present or -absent lineup either immediately or several weeks later. Compared to the immediate condition, the delay condition produced greater overconfidence and lower diagnosticity. However, for choosers at both retention intervals there was a meaningful CA relationship and diagnosticity was much stronger at high than low confidence levels.
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The combined postdictive value of postdecision confidence, decision time, and Remember-Know-Familiar (RKF) judgments as markers of identification accuracy was evaluated with 10 targets and 720 participants. In a pedestrian area, passers-by were asked for directions. Identifications were made from target-absent or target-present lineups. Fast (optimum time boundary at 6 seconds) and confident (optimum confidence boundary at 90%) witnesses were highly accurate, slow and nonconfident witnesses highly inaccurate. Although this combination of postdictors was clearly superior to using either postdictor by itself these combinations refer only to a subsample of choosers. Know answers were associated with higher identification performance than Familiar answers, with no difference between Remember and Know answers. The results of participants' post hoc decision time estimates paralleled those with measured decision times. To explore decision strategies of nonchoosers, three subgroups were formed according to their reasons given for rejecting the lineup. Nonchoosers indicating that the target had simply been absent made faster and more confident decisions than nonchoosers stating lack of confidence or lack of memory. There were no significant differences with regard to identification performance across nonchooser groups.
Article
Introduction Eyewitness identification research has mainly examined the identification accuracy of a single perpetrator but many actual crimes involve not one but several perpetrators. Objective The 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. Method The 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. Results Participants 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. Conclusion The results are discussed in terms of the number of perpetrators and line-up presentation types.
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Nadel, Jacobs, and colleagues have postulated that human memory under conditions of extremely high stress is “special.” In particular, episodic memories are thought to be susceptible to impairment, and possibly fragmentation, attributable to hormonally based dysfunction occurring selectively in the hippocampal system. While memory for highly salient and self‐relevant events should be better than the memory for less central events, an overall nonmonotonic decrease in spatio/temporal episodic memory as stress approaches traumatic levels is posited. Testing human memory at extremely high levels of stress, however, is difficult and reports are rare. Firefighting is the most stressful civilian occupation in our society. In the present study, we asked New York City firefighters to recall everything that they could upon returning from fires they had just fought. Communications during all fires were recorded, allowing verification of actual events. Our results confirmed that recall was, indeed, impaired with increasing stress. A nonmonotonic relation was observed consistent with the posited inverted u‐shaped memory‐stress function. Central details about emergency situations were better recalled than were more schematic events, but both kinds of events showed the memory decrement with high stress. There was no evidence of fragmentation. Self‐relevant events were recalled nearly five times better than events that were not self‐relevant. These results provide confirmation that memories encoded under conditions of extremely high stress are, indeed, special and are impaired in a manner that is consistent with the Nadel/Jacobs hippocampal hypothesis.
Article
Face recognition memory is often tested by the police using a photo lineup, which consists of one suspect, who is either innocent or guilty, and five or more physically similar fillers, all of whom are known to be innocent. For many years, lineups were investigated in lab studies without guidance from standard models of recognition memory. More recently, signal detection theory has been used to conceptualize lineup memory and to motivate receiver operating characteristic (ROC) analysis of competing lineup procedures. However, this movement is still in its infancy. Here, we present three competing signal-detection models of lineup memory, derive their likelihood functions, and fit them to empirical ROC data. We also introduce the notion that the memory signals generated by the faces in a lineup are likely to be correlated because, by design, they share many features. The models we investigate differ in their predictions about the effect that correlated memory signals should have on the ability to discriminate innocent from guilty suspects. The best-fitting model incorporates a principle known as "ensemble coding," a concept that applies to the presentation of any set of similar items (including the faces in a lineup). The ensemble model also accords with a previously proposed theory of eyewitness identification according to which the simultaneous presentation of faces in a lineup enhances discriminability compared to when faces are presented in isolation because it permits eyewitnesses to detect and discount non-diagnostic facial features.
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Eyewitness identifications play an important role in the investigation and prosecution of crimes, but it is well known that eyewitnesses make mistakes, often with serious consequences. In light of these concerns, the National Academy of Sciences recently convened a panel of experts to undertake a comprehensive study of current practice and use of eyewitness testimony, with an eye toward understanding why identification errors occur and what can be done to prevent them. The work of this committee led to key findings and recommendations for reform, detailed in a consensus report entitled Identifying the Culprit: Assessing Eyewitness Identification In this review, I focus on the scientific issues that emerged from this study, along with brief discussions of how these issues led to specific recommendations for additional research, best practices for law enforcement, and use of eyewitness evidence by the courts.
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Witnesses play a key role in criminal investigations. Research in estimator variables has aided criminal justice practitioners to estimate, post hoc, the likelihood of obtaining accurate testimony from a specific witness. Nonetheless, only a few studies have examined how violence and personality influence memory. The present study examines both variables with a student sample (N = 53). Participants were randomly divided between those who viewed a crime involving physical violence (n = 24) and those who watched an event that did not include physical violence (n = 29). Results found that physical violence increased the quantity of information recalled, and Honesty personality domain was positively correlated with memory performance. Nonetheless, the relationship between personality domains and memory performance appeared to be influenced and modified by the presence of physical violence. Under violent conditions personality domains of Emotionality and Openness appeared to be related with decreased memory accuracy, whereas Contentiousness appeared to be related with increased memory accuracy. This study enables a clearer picture to emerge of the effect that violence and personality have on memory and seeds the idea that claiming linear relationships between estimator variables and memory may be over-simplistic as variables appeared to be related among them when influencing eyewitness memory.
Book
This new edition to the classic book by ggplot2 creator Hadley Wickham highlights compatibility with knitr and RStudio. ggplot2 is a data visualization package for R that helps users create data graphics, including those that are multi-layered, with ease. With ggplot2, it's easy to: • produce handsome, publication-quality plots with automatic legends created from the plot specification • superimpose multiple layers (points, lines, maps, tiles, box plots) from different data sources with automatically adjusted common scales • add customizable smoothers that use powerful modeling capabilities of R, such as loess, linear models, generalized additive models, and robust regression • save any ggplot2 plot (or part thereof) for later modification or reuse • create custom themes that capture in-house or journal style requirements and that can easily be applied to multiple plots • approach a graph from a visual perspective, thinking about how each component of the data is represented on the final plot This book will be useful to everyone who has struggled with displaying data in an informative and attractive way. Some basic knowledge of R is necessary (e.g., importing data into R). ggplot2 is a mini-language specifically tailored for producing graphics, and you'll learn everything you need in the book. After reading this book you'll be able to produce graphics customized precisely for your problems, and you'll find it easy to get graphics out of your head and on to the screen or page. New to this edition:< • Brings the book up-to-date with ggplot2 1.0, including major updates to the theme system • New scales, stats and geoms added throughout • Additional practice exercises • A revised introduction that focuses on ggplot() instead of qplot() • Updated chapters on data and modeling using tidyr, dplyr and broom
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Psychological science has come to play an increasingly important role in the legal system by informing the court through expert testimony and by shaping public policy. In recent years, psychological research has driven a movement to reform the procedures that police use to obtain eyewitness identification evidence. This reform movement has been based in part on an argument suggesting that recommended procedures reduce the risk of false identifications with little or no reduction in the rate of correct identifications. A review of the empirical literature, however, challenges this no-cost view. With only one exception, changes in eyewitness identification procedures that reduce the risk of false identification of the innocent also reduce the likelihood of correct identification of the guilty. The implication that criminals may escape prosecution as a result of procedures implemented to protect the innocent makes policy decisions far more complicated than they would otherwise be under the no-cost view. These costs (correct identifications lost) and benefits (false identifications avoided) are discussed in terms of probative value and expected utility. © The Author(s) 2012.
Article
Few studies have investigated how stress affects eyewitness identification capabilities across development, and no studies have investigated whether retrieval context in conjunction with stress affects accuracy. In this study, one hundred fifty-nine 7- to 8- and 12- to 14-year-olds completed a high- or low-stress laboratory protocol during which they interacted with a confederate. Two weeks later, they attempted to identify the confederate in a photographic lineup. The lineup administrator behaved in either a supportive or a nonsupportive manner. Participants who experienced the high-stress event and were questioned by a supportive interviewer were most accurate in rejecting target-absent lineups. Results have implications for debates about effects of stress on eyewitness recall, how best to elicit accurate identifications in children, and developmental changes in episodic mnemonic processes.
Article
Eyewitness experiments do not induce the stress experienced by victims of crime. It is important to understand the effect of stress if results of laboratory studies are to be generalised to victims and witnesses of real crimes, but previous research has shown a mixed picture. The ability of visitors to the London Dungeon to describe and identify somebody encountered in the Horror Labyrinth was investigated, as a function of their state anxiety. To validate the measure of state anxiety, participants wore a wireless heart rate monitor whilst in the labyrinth. High state anxiety was associated with a higher heart rate. Subsequently, visitors completed measures of their state anxiety experienced whilst in the labyrinth and a measure of trait anxiety. High state anxiety was associated with reporting fewer correct descriptors of the target person, more incorrect details and making fewer correct identifications from a lineup. There was no effect of trait anxiety on eyewitness memory. Copyright © 2008 John Wiley & Sons, Ltd.