Wixted John T, Mickes Laura
Department of Psychology, University of California, San Diego.
Department of Psychology, Royal Holloway, University of London.
Psychol Rev. 2014 Apr;121(2):262-76. doi: 10.1037/a0035940.
The theoretical understanding of eyewitness identifications made from a police lineup has long been guided by the distinction between absolute and relative decision strategies. In addition, the accuracy of identifications associated with different eyewitness memory procedures has long been evaluated using measures like the diagnosticity ratio (the correct identification rate divided by the false identification rate). Framed in terms of signal-detection theory, both the absolute/relative distinction and the diagnosticity ratio are mainly relevant to response bias while remaining silent about the key issue of diagnostic accuracy, or discriminability (i.e., the ability to tell the difference between innocent and guilty suspects in a lineup). Here, we propose a signal-detection-based model of eyewitness identification, one that encourages the use of (and helps to conceptualize) receiver operating characteristic (ROC) analysis to measure discriminability. Recent ROC analyses indicate that the simultaneous presentation of faces in a lineup yields higher discriminability than the presentation of faces in isolation, and we propose a diagnostic feature-detection hypothesis to account for that result. According to this hypothesis, the simultaneous presentation of faces allows the eyewitness to appreciate that certain facial features (viz., those that are shared by everyone in the lineup) are non-diagnostic of guilt. To the extent that those non-diagnostic features are discounted in favor of potentially more diagnostic features, the ability to discriminate innocent from guilty suspects will be enhanced.
长期以来，对于从警方列队辨认中得出的目击证人辨认结果的理论理解，一直受到绝对决策策略和相对决策策略之间差异的指导。此外，长期以来，与不同目击证人记忆程序相关的辨认准确性一直是使用诊断率（正确辨认率除以错误辨认率）等指标来评估的。从信号检测理论的角度来看，绝对/相对差异和诊断率主要与反应偏差相关，而对于诊断准确性或辨别力（即从列队辨认中区分无辜嫌疑人和有罪嫌疑人的能力）这一关键问题却未作探讨。在此，我们提出一种基于信号检测的目击证人辨认模型，该模型鼓励使用（并有助于概念化）接收者操作特征（ROC）分析来衡量辨别力。最近的ROC分析表明，在列队辨认中同时呈现面孔比单独呈现面孔具有更高的辨别力，我们提出一种诊断性特征检测假设来解释这一结果。根据这一假设，同时呈现面孔能让目击证人认识到某些面部特征（即列队中每个人都共有的那些特征）对于判定有罪并无诊断价值。只要那些无诊断价值的特征被忽略，转而关注可能更具诊断价值的特征，那么区分无辜嫌疑人和有罪嫌疑人的能力就会得到增强。
