Browsing by Person "Mansour, Jamal K."

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Are multiple-trial experiments appropriate for eyewitness identification studies? Accuracy, choosing, and confidence across trials
(Springer, 2017-04-21) Mansour, Jamal K.; Beaudry, J. L.; Lindsay, R. C. L.
Eyewitness identification experiments typically involve a single trial: a participant views an event and subsequently makes a lineup decision. Compared to this single-trial paradigm, multiple-trial designs are more efficient but significantly reduce ecological validity and may affect the strategies participants use to make lineup decisions. We examined the effects of a number of forensically-relevant variables (i.e., memory strength, type of disguise, degree of disguise, and lineup type) on eyewitness accuracy, choosing, and confidence across 12 target-present and 12 target-absent lineup trials (N = 349; 8,376 lineup decisions). Rates of correct rejections and choosing (across both target-present and -absent lineups) did not vary across the 24 trials as reflected by main effects or interactions with trial number. Trial number had a significant but trivial quadratic effect on correct identifications (OR = 0.99) and interacted significantly, but again trivially, with disguise type (OR = 1.00). Trial number did not significantly influence participants' confidence in correct identifications, confidence in correct rejections, or confidence in target-absent selections. Thus, multiple-trial designs appear to have minimal effects on eyewitness accuracy, choosing, and confidence. Researchers should consider using multiple-trial designs for conducting eyewitness identification experiments.
Collective directional movement and the perception of social cohesion
(Wiley, 2020-01-03) Wilson, Stuart; Mansour, Jamal K.
We argue that perceivers associate collective directional movement – groups moving from one place to the next – with higher levels of social cohesion. Study 1 shows that pairs are rated as being more cohesive when described as engaging in directional movement compared to non-directional activities. Study 2 replicates this finding using film clips. Study 3 reveals that the proximity of directionally moving dyads is a better predictor of perceived cohesion than behavioural synchrony. Study 4 replicates the original finding and reveals that perceptions of common fate and shared goals both contribute to the effect, with the former having more predictive power than the latter. We suggest that collective directional movement is an invariant part of social environments and is utilised by perceivers to make inferences about social dynamics.
The confidence-accuracy relationship using scale versus other methods of assessing confidence
(Elsevier, 2020-03-19) Mansour, Jamal K.
Historically, researchers have collected eyewitness identification confidence using scales; however, in practice, eyewitnesses are more commonly asked for a verbal statement. In Experiment 1, participants viewed a simultaneous lineup and provided confidence in their own words, by explaining why they made their decision, or by selecting from statements made by real eyewitnesses, and then provided a scale rating (0-100%) or provided only the scale rating. In Experiment 2, participants viewed a sequential lineup and provided confidence in their own words followed by the scale rating or only the scale rating. Confidence predicted identification accuracy in all conditions, although verbal statements were highly variable and challenging to interpret. For example, only when scale-based confidence was high (80%+) did interpretation of the verbal confidence statement reliably align with scale-based confidence. These data highlight the complexity of verbal confidence statements and the need to establish meaningful boundaries for interpreting verbal confidence statements.
Creating a Cross-Race Effect Inventory to Postdict Eyewitness Accuracy
(American Psychological Association, 2025-07-28) Töredi, Dilhan; Mansour, Jamal K.; Jones, Sian; Skelton, Faye; McIntyre, Alex
Objective: The Cross-Race Effect (CRE) is a reliable and robust phenomenon, whereby individuals better recognize faces that belong to their race compared to another race. Our goal was to develop a self-report Inventory (i.e., CRE-I) that brings together known predictors of the CRE to improve postdiction of cross-race eyewitness accuracy. Hypotheses: We expected a CRE for White and Asian participants. We anticipated that developed CRE-I subscales would correlate positively with extant (some modified) scales and predict accuracy. Method: Participants completed four trials (two White targets and two Asian targets). For each trial, they watched a mock crime video, performed a distractor task, made a sequential lineup decision (target-present or target-absent), and indicated confidence in their lineup decision. After all trials, participants completed the potential items for the CRE-I. Results: We replicated prior findings of a CRE for White participants but did not find a CRE for Asian participants. Exploratory factor analysis produced an inventory (the CRE-I) with reliable scales for White eyewitnesses: general face recognition ability, race-specific face recognition ability, racial attitudes, quantity of contact, quality of contact, motivated individuation, and cognitive disregard. Responses to several scales predicted identification accuracy. In particular, three scales of the CRE-I predicted identification accuracy beyond the predictiveness of confidence: race-specific face recognition ability, racial attitudes towards White people, and motivated individuation of White people. Conclusions: Variables suggested separately by the perceptual expertise hypothesis and the social cognitive hypothesis predicted identification accuracy, providing support for integrative models of the CRE. The CRE-I contributes to the CRE literature both in terms of theory—by showing which factors among many may best relate to recognition—and practice—by improving evaluations of eyewitness reliability.
Evaluating lineup fairness: Variations across methods and measures
(American Psychological Association, 2016-09-29) Mansour, Jamal K.; Beaudry, Jennifer L.; Kalmet, Natalie; Bertrand, Michelle I.; Lindsay, R. C. L.
Triers of fact sometimes consider lineup fairness when determining the suggestiveness of an identification procedure. Likewise, researchers often consider lineup fairness when comparing results across studies. Despite their importance, lineup fairness measures have received scant empirical attention and researchers inconsistently conduct and report mock-witness tasks and lineup fairness measures. We conducted a large-scale, online experiment (N = 1010) to examine how lineup fairness measures varied with mock-witness task methodologies as well as to explore the validity and reliability of the measures. In comparison to descriptions compiled from multiple witnesses, when individual descriptions were presented in the mock-witness task, lineup fairness measures indicated a higher number of plausible lineup members but more bias towards the suspect. Target-absent lineups were consistently estimated to be fairer than target-present lineups-which is problematic because it suggests that lineups containing innocent suspects are less likely to be challenged in court than lineups containing guilty suspects. Correlations within lineup size measures and within some lineup bias measures indicated convergent validity and the correlations across the lineup size and lineup bias measures demonstrated discriminant validity. The reliability of lineup fairness measures across different descriptions was low and reliability across different sets of mock witnesses was moderate to high, depending on the measure. Researchers reporting lineup fairness measures should specify the type of description presented, the amount of detail in the description, and whether the mock witnesses viewed target-present and/or -absent lineups.
An Examination of the Cognitive Processes Related to Eyewitness Lineup Decisions
(Taylor & Francis Group, 2025-07-23) Mansour, Jamal K.; Stepan, Michelle E.; Berkowitz, Shari R.; Peltier, Chad; Fenn, Kimberly M.
Given the magnitude of errors in the criminal justice system, it is vital to increase our capacity to predict when an eyewitness is likely to be accurate. The aim of this work was to examine cognitive processes important for correct lineup responses and to develop a theoretically-driven model of the relative strength of these processes and the interactions between them for predicting the likelihood of an accurate lineup decision. We used sleep to manipulate memory strength and assessed decision process objectively, using eye tracking, and subjectively, using a questionnaire. We then modeled the influence of memory strength and decision process on correct identifications in a target-present lineup (Experiment 1) and correct rejections in a target-absent lineup (Experiment 2). Our subjective measure of decision process was the only predictor of correct identifications. Memory strength and decision process predicted the likelihood of correct rejections, and did so largely independently from one another, but the subjective measure was the stronger predictor. Combining the data from both experiments suggested that decision processes mediate the relationship between memory strength and identification accuracy. These results can inform theories of how cognitive processes interact to influence lineup decisions.
Examining how lineup practices of Canadian and U.S. police officers adhere to their national best practice recommendations
(2018-11-25) Bertrand, Michelle I.; Lindsay, R. C. L.; Mansour, Jamal K.; Beaudry, Jennifer L.; Kalmet, Natalie; Melsom, Elisabeth I.
Canadian (N = 117) and U.S. (N = 167) police officers completed a survey about their lineup construction and administration practices. We compared their responses to national policy recommendations in both countries, which had five similar and four different recommendations. We expected that if officers' lineup procedures corresponded with policy recommendations, the countries would have similar procedures when recommendations were similar, but different procedures in line with their respective policies when recommendations were different. We generally found the predicted pattern of results. Findings were especially striking when the policies differed. Some procedures were largely in line with policy recommendations (e.g., double-blind testing), others corresponded to some extent (e.g., sequential lineups), and others were largely not followed (e.g., providing instruction that it is as important to exonerate the innocent as it is to convict the guilty). We cautiously interpret these findings as demonstrating that policy has some influence on procedures. However, even though our hypotheses were generally supported, there was considerable variation in procedures that did not correspond with policy recommendations. Our findings illustrate the importance of assessing user reactions to policy recommendations and examining barriers to policy implementation.
Eyewitness Decision Processes: A Valid Reflector Variable
(Wiley, 2024-12-15) Mansour, Jamal K.; Beaudry, Jennifer; Nguyen, Mai-Tram; Groncki, Roy
Identification accuracy can be predicted from eyewitnesses' self-reported decision processes but the evidence of their ability to improve prediction when confidence and response time are included is mixed and minimal. Typically, decision processes are measured via one or five self-report questions; we explored whether a more nuanced questionnaire could improve prediction. Participants viewed a mock-crime video, made a target-present or -absent lineup decision, and completed 17 decision process items. An exploratory factor analysis on choosers' (n = 391) responses revealed three correlated factors, broadly reflecting automatic response, relative judgment, and absolute judgment. The three-factor solution had good internal reliability (McDonald's ωs = 0.93, 0.89, and 0.74, respectively). Scores produced from the questions loading on the automatic response and relative judgment factors improved predictions of accuracy compared to using confidence and response time alone. Self-reported decision processes may be an easy-to-administer and useful reflector of identification accuracy.
Face Recognition in Eyewitness Memory
(Oxford University Press, 2011-07) Lindsay, R. C. L.; Mansour, Jamal K.; Bertrand, M. I.; Kalmet, N.; Melsom, E.; Calder, Andy; Haxby, James; Johnson, Mark; Rhodes, Gillian
Two types of variables impact face recognition: estimator variables that cannot be controlled and system variables that are under direct control by the criminal justice system. This article addresses some of the reasons that eyewitnesses are prone to making errors, particularly false identifications. It provides a discussion of the differences between typical facial memory and eyewitness studies and shows that the two areas generally find similar results. It reviews estimator variable effects and focuses on system variables. Traditional facial recognition researchers rarely study system variables but reveal important factors that police and policy makers should consider with regard to eyewitness identification and the courts. It concludes that there is still room for considerable improvement in identification procedures and wants to encourage more system variable research as a means of reducing wrongful convictions.
Factors Influencing the Eyewitness Identification Accuracy of Child Witnesses
(Irwin Law, 2011-07) Kalmet, N.; Lindsay, R. C. L.; Bertrand, M. I.; Mansour, Jamal K.; Anand, Sanjeev
How to measure lineup fairness: Concurrent and predictive validity of lineup-fairness measures
(Taylor and Francis Group, 2024-02-01) Lee, Jungwon; Mansour, Jamal K.; Penrod, Steven D.
The current study examined the concurrent and predictive validity of four families of lineupfairness 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.
Impact of disguise on identification decisions and confidence with simultaneous and sequential lineups
(American Psychology-Law Society - APA Division 41, 2020-12) Mansour, Jamal K.; Beaudry, Jennifer L.; Bertrand, Michelle I.; Kalmet, Natalie; Melsom, Elisabeth I.; Lindsay, Roderick C. L.
Objective: Prior research indicates disguise negatively affects lineup identifications but the mechanisms by which disguise works have not been explored and different disguises have not been compared. We investigated how two different types of disguise, four levels of varying degrees of coverage, and lineup type influence eyewitnesses' identification decisions, accuracy, and confidence. Hypotheses: We predicted that identification accuracy would decrease as the disguise covered more of a perpetrator's face. We also predicted that type of disguise–stocking mask versus sunglasses and/or toque (i.e., knitted hat)–would influence identifications, but we had conflicting predictions about which disguise would impair their performance more. Method: In two experiments (Ns = 87 and 91) we manipulated degree of coverage by two different types of disguise: a stocking mask or sunglasses and toque. Participants viewed mock-crime videos followed by simultaneous or sequential lineups. Results and Conclusions: Disguise and lineup type did not interact. In support of the view that disguise prevents encoding, identification accuracy generally decreased with degree of disguise. For the stocking disguise, however, full and 2/3 coverage led to approximately the same rate of correct identifications—which suggests that disrupting encoding of specific features may be as detrimental as disrupting a whole face. Accuracy was most affected by sunglasses and we discuss the role meta-cognitions may have played. Lineup selections decreased more slowly than accuracy as coverage by disguise increased, indicating witnesses are insensitive to the effect of encoding conditions on accuracy.
The Impact of Minority Status on the Cross-Race Effect: A Critical Review
(SAGE Publications, 2025-06-30) Töredi, Dilhan; Mansour, Jamal K.; Jones, Sian; Skelton, Faye; McIntyre, Alex
Meta-analyses have consistently demonstrated the robustness of the cross-race effect (CRE; i.e., better recognition of same-race faces compared to different-race faces). These analyses have unveiled variations in the dependent variables associated with the CRE across combinations of participant and target races (Lee & Penrod, 2022; Meissner & Brigham, 2001). However, the underlying factors driving these variations remain poorly understood. We posit that although the CRE is robust, its generalizability may be contingent on the specific racial groups compared, particularly when contrasting majority and minority racial groups. In this comprehensive review, we delve into the dynamics of the CRE across distinct racial groups and explore how minority status may influence research outcomes. We considered the manuscripts included in the latest meta-analyses of the CRE with a spotlight on minority status. We suggest that minority-race status may explain why many studies considering non-White participants do not show a CRE. The CRE might not be as robust as it appears to be because much of the research on the effect has focused on majority-race participants and minority-race faces. Going forward, researchers should consider incorporating measures relevant to the minority effect, fully crossing participant and target races, and studying a greater variety of races.
“Only your first yes will count”: The impact of pre-lineup instructions on sequential lineup decisions
(American Psychological Association, 2020-10-29) Horry, Ruth; Fitzgerald, Ryan J.; Mansour, Jamal K.
When administering sequential lineups, researchers often inform their participants that only their first yes response will count. This instruction differs from the original sequential lineup protocol and from how sequential lineups are conducted in practice. Participants (N = 896) viewed a videotaped mock crime and viewed a simultaneous lineup, a sequential lineup with a first-yes-counts instruction, or a sequential control lineup (with no first-yes-counts instruction); the lineup was either target-present or target-absent. Participants in the first-yes-counts condition were less likely to identify the suspect and more likely to reject the lineup than participants in the simultaneous and sequential control conditions, suggesting a conservative criterion shift. The diagnostic value of suspect identifications, as measured by partial Area Under the Curve, was lower in the first-yes-counts lineup than in the simultaneous lineup. Results were qualitatively similar for other metrics of diagnosticity, though the differences were not statistically significant. Differences between the simultaneous and sequential control lineups were negligible on all outcomes. The first-yes-counts instruction undermines sequential lineup performance and produces an artefactual simultaneous lineup advantage. Researchers should adhere to sequential lineup protocols that maximize diagnosticity and that would feasibly be implemented in practice, allowing them to draw more generalizable conclusions from their data.
The effect of evidence type, identification accuracy, line-up presentation, and line-up administration on observers' perceptions of eyewitnesses
(The British Psychological Society, 2013-10-12) Beaudry, Jennifer L.; Lindsay, Roderick C. L.; Leach, Amy-May; Mansour, Jamal K.; Bertrand, Michelle I.; Kalmet, Natalie
Purpose People tend to believe eyewitness testimony and have difficulty assessing the accuracy of eyewitness identifications. This study examines observers' perceptions of eyewitness identifications made under various line-up presentation and administration conditions. We also investigate whether observers' ability to discriminate between accurate and inaccurate identifications is enhanced by viewing video-recorded identification decisions rather than eyewitness testimony. Methods Each participant (N = 432) viewed a video of an accurate or inaccurate eyewitness providing testimony and/or making an identification decision. Identifications were obtained from simultaneous or sequential line-ups conducted under double-blind, single-blind, or post-identification feedback administration conditions. Results Exposure to eyewitness testimony was associated with a bias to believe the evidence; exposure to the identification decision eliminated the response bias, however, it did not improve observer sensitivity to identification accuracy. Viewing the identification decision resulted in greater belief of accurate than inaccurate identifications when eyewitnesses chose from simultaneous - but not sequential - line-ups. Regardless of evidence type or identification accuracy, observers were more likely to believe eyewitnesses who received confirmatory post-identification feedback compared to the non-feedback conditions. Conclusions Presenting a video record of the identification decision neither improved observers' ability to discriminate between accurate and inaccurate eyewitness identifications nor reduced belief of identifications obtained from suggestive procedures. Further research is warranted before presenting video-recorded identification procedures in court. 2013 The British Psychological Society.
Understanding the weapon focus effect: The role of threat, unusualness, exposure duration, and scene complexity
(Wiley, 2018-12-21) Mansour, Jamal K.; Hamilton, Claire M.; Gibson, Matthew T.
We examined the role of exposure duration and scene complexity on the weapon focus effect (WFE). Memory for the mock crime was affected more by a weapon than an unusual but nonthreatening object. Threat reduced correct identifications when the event was short but not long; duration of the event did not interact with unusualness. Additionally, we found a WFE for target‐absent lineup decisions, but only for the accomplice lineup, not the object‐wielding perpetrator's lineup. We discuss the implications of these results for illuminating the mechanisms that elicit the WFE.
Validity of mock-witness measures for assessing lineup fairness
(Taylor & Francis, 2021-03-29) Lee, Jungwon; Mansour, Jamal K.; Penrod, Steven D.
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.
Variability in verbal eyewitness confidence
(Wiley, 2024-03-19) Pennekamp, Pia; Mansour, Jamal K.; Batstone, Rhiannon
Typically, an eyewitness' verbal confidence is used to judge the reliability of their lineup identification. Across three experiments (N = 3976), we examined eyewitnesses' own words confidence in their lineup decision. For identification decisions (n = 1099), we identified 781 quantitatively unique responses representing 132 qualitatively unique statements that could be categorized into low, medium, and high confidence. For rejectors (n = 781), we identified 599 quantitatively unique responses representing 143 qualitatively unique responses that could be categorized into low, medium, and high confidence. Most participants provided a verbal phrase (e.g., pretty sure) but a significant proportion—34.19% of identifiers and 29.05% of rejectors—provided numbers (e.g., 80%). The present data highlight the variability in how confidence is expressed. The criminal justice system would benefit from guidance for interpreting verbal confidence. We provide a picture of eyewitnesses' verbal confidence as a first step.
Working Memory Capacity Is Related to Eyewitness Identification Accuracy, but Selective Attention and Need for Cognition Are Not
(2025-09-16) Töredi, Dilhan; Mansour, Jamal K.; Jones, Sian; Skelton, Faye; McIntyre, Alex
Individual differences in working memory capacity, selective attention, and need for cognition were investigated as postdictors—variables indicating the likelihood that an identification is accurate—using same-race and cross-race lineups. We also explored whether these variables improve predictions of identification accuracy when considering confidence and response time. White participants (N = 274) completed individual differences measures, watched four mock-crime videos (2 Asian targets, 2 White targets), made lineup decisions, and rated their confidence. Working memory capacity predicted identification accuracy and target-present accuracy but not target-absent accuracy. A regression model with confidence, response time, and working memory capacity explained more variance than a model with confidence and response time alone, indicating that working memory capacity tells us more about identification accuracy than extant reflector variables about identification accuracy.