The Role of Diagnostic vs. Non-Diagnostic Facial Features in Eyewitness Identification

无辜的嫌疑犯被错误地判定犯有他们没有犯下的罪行的问题，以及有罪的嫌疑犯被错误地释放到社会中的平行问题，在很大程度上归因于目击者记忆的不可靠性。大量关于目击者记忆的研究都集中在减少对无辜嫌疑人的错误指认上（从而减少他们被错误定罪的可能性）。然而，减少这一不幸错误的方法往往会增加补充错误，即未能确定犯罪嫌疑人的错误。这种折衷可能被认为是可以接受的，但更好的方法是同时减少这两种错误。到目前为止，很少有研究考虑到这一目标，但这是这里提出的研究目标。 特别是，这项研究询问可以做些什么来提高目击者的辨别力（即，区分无辜和有罪嫌疑人的能力）。 为了回答这个问题，这项研究以一种新的目击者识别理论为指导：诊断特征检测假说。 提高目击者记忆程序的可辨别性具有显著的更广泛的影响，因为它将减少对无辜者的错误识别，同时增加对有罪者的识别。传统的同步阵容（其中6张脸同时显示给证人），较新的顺序阵容（其中6张脸一次一张地显示给证人），以及showup程序（其中只有一张脸显示给证人以决定是/否）。事实上，所有的警察部门都使用了现身程序（因为这通常是快速调查中唯一的可能性），近30%的警察部门已经从同时列队程序转向顺序程序。然而，与以前认为的相反，最近的工作发现，showup和顺序阵容都不如同时程序（即，与其他两种程序相比，同时程序可以减少对无辜嫌疑人的错误识别，同时增加对有罪嫌疑人的正确识别）。鉴于常见的和可能继续使用的showup程序和顺序阵容，本研究提出了一系列的实验，调查简单方便的方法来提高这些目击者识别程序的诊断准确性。

The problem of innocent suspects being mistakenly convicted of a crime they did not commit and the parallel problem of guilty suspects being mistakenly released into society are attributable in no small part to the fallibility of eyewitness memory. A great deal of eyewitness memory research has focused on reducing false identifications of innocent suspects (thereby reducing the chances that they will be wrongly convicted). However, methods that reduce that unfortunate error often have the effect of increasing the complementary error, namely, the error of failing to identify guilty suspects. That tradeoff might be considered acceptable, but a better approach would involve reducing both errors simultaneously. To date, very little research has been conducted with that goal in mind, but it is the goal of the research proposed here. In particular, this research asks what can be done to enhance eyewitness discriminability (i.e., the ability to tell the difference between innocent and guilty suspects). To answer this question, the research is guided by a new theory of eyewitness identification: the diagnostic feature-detection hypothesis. Enhancing the discriminability of eyewitness memory procedures has significant broader impacts because it would decrease misidentifications of the innocent while at the same time increasing identifications of the guilty.This project will focus on three widely used eyewitness identification procedures: the traditional simultaneous lineup (in which 6 faces are shown to the witness simultaneously), the newer sequential lineup (in which the 6 faces are shown to the witness one at a time), and the showup procedure (in which only one face is shown to a witness for a yes/no decision). Virtually all police departments make use of the showup procedure (because it is often the only possibility in a fast-moving investigation), and nearly 30% of police departments have switched from the simultaneous lineup procedure to the sequential procedure. However, contrary to what was previously believed, recent work has found that both the showup and the sequential lineup are inferior to the simultaneous procedure (i.e., the simultaneous procedure can reduce false identifications of innocent suspects while at the same time increasing correct identifications of guilty suspects compared to the other two procedure). Given the common and likely continued use of the showup procedure and sequential lineup, this research proposes a series of experiments to investigate simple and convenient ways to enhance the diagnostic accuracy of these eyewitness identification procedures.