Eyewitness identification discriminability: ROC analysis versus logistic regression

To reach conclusions regarding the respective accuracy of two conditions, eyewitness researchers evaluate correct and false identification rates computed across participants. Two approaches typically are employed. One approach relies on ratio-based probative value measures; but Wixted and Mickes (2012) and Gronlund, Wixted, and Mickes (2014) showed that these measures fail to disentangle an assessment of accuracy (i.e., discriminability between guilty and innocent suspects) from response bias (i.e., a willingness to make a response). Our focus is on a second approach, logistic regression analyses of the correct and of the false identification rates. Logistic regression also fails to disentangle discriminability from bias. Therefore, it only can denote the most accurate condition in limited circumstances. The best approach for reaching the proper conclusion regarding which condition is most accurate is to use receiver operator characteristic (ROC) analysis. Simulated ROC data illustrate the problem with a reliance on logistic regression to assess accuracy.     

Eyewitness identification: information gain from incriminating and exonerating behaviors

An information-gain approach to the analysis and interpretation of eyewitness identification data is described. The information-gain analysis is grounded in Bayesian statistics, permitting the important role of prior probabilities to be explored. This approach also forces a more complete treatment of the data and reveals important patterns that have escaped previous attention in the eyewitness identification literature. Particularly important is the ability of information-gain analyses to make salient the exonerating value of eyewitness behaviors rather than just their incriminating value. Analyses of sample data sets show how the exonerating value of filler identifications and "not there" responses can actually exceed the incriminating value of identifications of the suspect at certain points in the distribution of prior probabilities.     

Eyewitness identification accuracy and response latency: the unruly 10-12-second rule

Data are reported from 3,213 research eyewitnesses confirming that accurate eyewitness identifications from lineups are made faster than are inaccurate identifications. However, consistent with predictions from the recognition and search literatures, the authors did not find support for the "10-12-s rule" in which lineup identifications faster than 10-12 s maximally discriminate between accurate and inaccurate identifications (D. Dunning & S. Perretta, 2002). Instead, the time frame that proved most discriminating was highly variable across experiments, ranging from 5 s to 29 s, and the maximally discriminating time was often unimpressive in its ability to sort accurate from inaccurate identifications. The authors suggest several factors that are likely to moderate the 10-12-s rule.     

Eyewitness identification in simultaneous and sequential lineups: an investigation of position effects using receiver operating characteristics

For decades, sequential lineups have been considered superior to simultaneous lineups in the context of eyewitness identification. However, most of the research leading to this conclusion was based on the analysis of diagnosticity ratios that do not control for the respondent’s response criterion. Recent research based on the analysis of ROC curves has found either equal discriminability for sequential and simultaneous lineups, or higher discriminability for simultaneous lineups. Some evidence for potential position effects and for criterion shifts in sequential lineups has also been reported. Using ROC curve analysis, we investigated the effects of the suspect’s position on discriminability and response criteria in both simultaneous and sequential lineups. We found that sequential lineups suffered from an unwanted position effect. Respondents employed a strict criterion for the earliest lineup positions, and shifted to a more liberal criterion for later positions. No position effects and no criterion shifts were observed in simultaneous lineups. This result suggests that sequential lineups are not superior to simultaneous lineups, and may give rise to unwanted position effects that have to be considered when conducting police lineups.     

ROCs in Eyewitness Identification: Instructions versus Confidence Ratings

From the perspective of signal detection theory, different lineup instructions may induce different levels of response bias. If so, then collecting correct and false identification rates across different instructional conditions will trace out the receiver operating characteristic (ROC)—the same ROC that, theoretically, could also be traced out from a single instruction condition in which each eyewitness decision is accompanied by a confidence rating. We tested whether the two approaches do in fact yield the same ROC. Participants were assigned to a confidence rating condition or to an instructional biasing condition (liberal, neutral, unbiased, or conservative). After watching a video of a mock crime, participants were presented with instructions followed by a six‐person simultaneous photo lineup. The ROCs from both methods were similar, but they were not exactly the same. These findings have potentially important policy implications for how the legal system should go about controlling eyewitness response bias.Copyright © 2017 John Wiley & Sons, Ltd.     

Eyewitness Errors in the Free Recall of Actions

Although eyewitness testimony is often unreliable, its quality is not uniformly poor. Previous research indicates that the most accurate type of testimony involves the unstructured recall of actions. The present study replicates the finding that confabulation, particularly the complete fabrication of nonexistent actions, is rare. Our results also extend earlier work by revealing that the few errors that did occur were spread evenly across subjects—with most subjects making 0 or 1 error and with no subjects making more than 3 errors. Furthermore, action memory errors form a heterogeneous set—there were few commonly recurring or predictable errors. Our attempts to increase error frequency by the use of suggestive implications and rapid action sequences were unsuccessful. Practical aspects of evaluating action memory testimony are discussed, with special reference to cases involving multiple eyewitnesses.     

Eyewitness testimony: tracing the beliefs of Swedish legal professionals

This paper examines beliefs held by Swedish legal professionals about eyewitness testimony. In a survey including questions about 13 key issues of eyewitness testimony, three groups were investigated: police officers (n = 104), prosecutors (n = 158), and judges (n = 251). The response rate was 74%. Examples of findings are that the beliefs were in line with scientific findings concerning the weapon focus effect, but were not in line for simultaneous vs. sequential lineups. Between-group differences were found for seven items. Judges were much more sceptical than police officers about the reliability and completeness of children's testimonies. The groups seldom agreed about one answer alternative, and they reported not being up to date about scientific research on eyewitness testimony. The results suggest that some important research findings have reached those working on the field. However, they hold many wrongful beliefs about eyewitness testimony, beliefs that might compromise the accuracy of legal decisions.     

Children's Eyewitness Suggestibility: Memory Trace Strength Revisited

This study investigated memory trace strength and the eyewitness suggestibility effect in 5- and 9-year-old children. Children were first presented with a picture story and then, on the next day, were read a post-event summary containing a number of misleading details. Trace strength was manipulated by repetition of the original and/or the post-event details. Children were given either a standard or a modified recognition test on their memories for picture story details one day after presentation of misleading suggestions. Both age groups were found to be suggestible in each recognition test condition. On the modified test, suggestibility was greatest when the post-event trace was strong and the original trace was weak. Theoretical accounts of the suggestibility effect in children and of memory trace strength are discussed in the light of these findings.     

不同列队呈现方式下反馈对目击证人辨认自信心的影响

采用辨认后反馈范式研究不同队列呈现方式下反馈对目击证人辨认自信心的影响。结果发现：（1）所有辨认者中,反馈组被试自信心显著高于控制组被试的自信心;反馈方式与辨认选择的交互作用显著,辨认选择与列队呈现方式的交互作用显著;（2）积极辨认者中,反馈组被试的自信心显著高于控制组被试的自信心;正确辨认被试的自信心显著高于错误辨认被试的自信心。结果表明：目击辨认中存在辨认后反馈效应;积极辨认者中辨认自信心可以作为辨认准确性的一个参考指标。     

Discordant identification in critical incident stress

Conversations with a witness to a violent episode of hostage-taking lead the author to reflect on the importance of understanding the role of unconscious identifications in conducting group debriefings with trauma survivors. Individuals with discordant identifications, identifications which run counter to the usual experience, present special challenges to leaders of critical-incident stress debriefings. Such identifications reveal much about the dynamics of calling to the helping professions and caring within them, and may serve a parabolic function, revealing aspects of God and community otherwise hidden. and was earlier on the faculty of the Psychiatry and Religion Program at Union Theological Seminary in New York. His bookFreud's Concept of Passivity was recently published by International Universities Press.     

Learning under stress: the inverted-U-shape function revisited

Although the relationship between stress intensity and memory function is generally believed to follow an inverted-U-shaped curve, strikingly this phenomenon has not been demonstrated under the same experimental conditions. We investigated this phenomenon for rats' performance in a hippocampus-dependent learning task, the radial arm water maze (RAWM). Variations in stress intensity were induced using different water temperatures (25°C, 19°C, and 16°C), which elicited increased plasma corticosterone levels. During spatial training over three consecutive days, an inverted-U shape was found, with animals trained at 19°C making fewer errors than animals trained at either higher (16°C) or lower (25°C) stress conditions. Interestingly, this function was already observed by the last trial of day 1 and maintained on the first day trial of day 2. A long-term recall probe test administered under equal temperature conditions (20°C) revealed differences in performance according to the animals' former training conditions; i.e., platform searching for rats trained at 25°C was less accurate than for rats trained at either 16°C or 19°C. In reversal learning, groups trained at both 19°C and 25°C showed better performance than the 16°C group. We also found an interaction between anxiety and exploration traits on how individuals were affected by stressors during spatial learning. In summary, our findings confirm, for the first time, the existence of an inverted-U-shape memory function according to stressor intensity during the early learning and memory phases in a hippocampus-dependent task, and indicate the existence of individual differences related to personality-like profiles for performance at either high or low stress conditions.     

The Headscarf Effect: Direct Evidence from the Eyewitness Identification Paradigm

Internal and external features dominate familiar and unfamiliar face recognition, respectively. However, this finding is not universal; Egyptians showed a robust internal‐feature advantage for processing unfamiliar faces (Megreya & Bindemann, 2009). This bias was speculatively attributed to their long‐term experiences for individuating female faces with headscarves, which completely cover the external features. Here, we provided an empirical test for this suggestion. Participants from Egypt and UK were presented with a staged crime, which was committed by an own‐race woman with or without a headscarf. All participants were then asked to identify the culprit from a line‐up involving 10 faces with or without headscarves. British participants showed an advantage when the culprit left her hair uncovered. In contrast, Egyptian observers showed an advantage when the culprit wore a headscarf. This Egyptian headscarf effect was also replicated using British faces, suggesting that it reflects a specific characteristic of participant nationality rather than face nationality. These results therefore provide evidence for how culture influences cognition. Copyright © 2011 John Wiley & Sons, Ltd.     

目击辨认研究概览

目击辨认的结果作为证据对于法庭判决具有重要意义。DNA证据显示辨认似乎不可靠,心理学家试图了解影响辨认准确性的因素。文章介绍了西方目击辨认研究的范式,估计变量和系统变量对辨认的影响,并分析目击辨认研究存在的理论缺乏和外部效度问题,从而为今后研究提供参考