警方调查人员经常要求目击证人提供犯罪嫌疑人的口头描述。这样描述提供关键信息,警方在调查使用,从识别可能的嫌疑人附近的犯罪,为杯子照片的选择书籍或阵容标识数组,建设草图或复合材料分发给公众。虽然对人的描述往往是准确的,但不幸的是,它们往往也缺乏足够的细节来找出一个嫌疑犯。
数量与人物描述的质量
众多档案研究检测了实际情况下提供的人描述的数量和质量。平均而言,目击者倾向于提供7到10个描述符,这些描述符往往是与随后识别的被告人相当一致的(或一致)。不幸的是,目击者提供的绝大多数描述符是普遍的,包括性别,种族,年龄,高度,体重,构建和肤色等特征。肇事者佩戴的衣服的各个方面也经常提及,但这些特征只提供了在犯罪后立即识别嫌疑人的短暂机会。目击者很少提及更具体的面部特征(例如眼睛颜色,头发颜色或风格和面部形状),并且包括的那些倾向于聚焦在面部的上部。一起占据,目击者似乎为犯罪者提供了准确的一般印象,但经常未能包含更具体的面部细节。证人描述的实验室研究倾向于同意真实证人的研究,表明虽然目击者通常提供准确的描述,但是它们很少包括对个体脸部的描述符可能是有用的。
影响描述准确性的因素
研究表明,各种认知和社会心理因素可以影响见证人的描述的准确性。首先,编码的因子是当证人与犯罪者相互作用或观看犯罪者时出现的临界事件时发生的因素。例如,低水平的照明,证人与犯罪者之间的距离更大,是观察肇事者的短暂时间,证人部分的压力或焦虑的经验(有时基于武器的存在),并在酒精或药物的影响下证明了,所有人都被证明可以降低人描述的准确性和完整性。其次,在编码和检索的时间的时间之间可能发生因素的子集(即,在保留间隔期间)以影响证人描述的准确性。For example, longer delays between encoding and retrieval have been shown to significantly reduce the quality of descriptions provided by witnesses, and exposure to “misinformation” (as described later in this research paper) has been demonstrated to significantly impair a witness’s memory and thereby his or her person description. Finally, certain characteristics of the witness can influence the quality of his or her person description. In particular, adults tend to provide more detailed descriptions than do children, though few differences in the accuracy of person descriptions have been noted between these two populations. Similarly, young adults are superior at recalling person descriptions when compared with middle-aged and elderly adults. Interestingly, unlike the cross-race effect in face identification, few differences in accuracy have been noted when individuals attempt to describe faces of another, less familiar race or ethnicity.
获取人员描述的方法
面试技术,如功能清单,呼叫召回和自由召回方法是诱因来自目击者的人描述的调查人员的良好实践。然而,无论使用哪种技术,都证明了完整但准确的描述已经非常困难。可能,最常见的获取人称描述的方法只是让证人自由描述他们记得犯罪者的内容。虽然这种自由召回技术定期导致高度准确的描述,但是从召回中省略了区分特征的关键细节。Consequently, it is common practice for investigators to ask more direct, follow-up questions about specific features (e.g., “Do you remember if the man had facial hair?”) or to attempt to confirm the identity of a suspect that they have identified (e.g., “Did the man have short black hair and blue eyes?”). Studies suggest that such leading questions can be very dangerous in that they can “misinform” a witness’s original memory for the perpetrator and subsequently impair his or her ability to both provide an accurate description and identify the perpetrator. Research on feature checklist techniques similarly suggest that providing witnesses with numerous descriptors regarding a face can create confusion in memory and lead them to report the presence of features that they are actually unsure of. Finally, witnesses to a crime are often asked to describe the perpetrator many times over the course of an investigation. Research suggests that this process of repeated retrieval can have both positive and negative effects. On the positive side, repeatedly recalling information has been shown to lead to increases in recalled information and to offer some “protection” to the memory trace. Unfortunately, erroneous details generated during early retrieval episodes are also repeatedly recalled over time with increased confidence.
企图开发面试技术来最大化描述完整性而不牺牲准确性,认知面试可能是最着名的。与其他“标准”的自由召回技术相比,已经证明可靠地改善人物描述的完整性。不幸的是,一些研究表明,认知面试导致描述准确性的略有成本,以增加的错误。这导致了一些研究人员建议,警告证人在提供人称描述符方面谨慎,最终可能会产生最大的准确性,并同时保护证人的内存免受细节的组织。
描述 - 识别关系
它似乎直观地,能够提供肇事者的准确言语描述的目击者也能够随后以更高的准确度识别肇事者;然而,在研究文献中,在描述和识别准确度之间的这种看似明显的关系尚未始终如一地展示。例如,在被称为口头过性效应的情况下,研究人员已经证明,要求参与者提供面部的口头描述实际上可以损害它们随后从类似照片阵列识别面对的能力。相比之下,其他研究表明,通过要求参与者在测试前提供口头描述,可以促进(或增强面孔的识别。使用各种描述质量的各种措施,包括各种描述质量的措施(包括准确性指标(报告的正确细节的比例),完整性(报告的正确细节比例),完整性(报告的正确细节的比例)的识别能力之间的具体关系报道),报告的正确和不正确的细节的频率以及所提供的描述与随后识别的面部之间的一致性。总的来说,描述精度和识别准确性之间似乎是一个小而可靠的相关性,并且这种效果似乎特别考虑在描述中生成的不正确细节的频率。Given the small size of the relationship between description and identification of faces, it appears possible that both memory tasks rely on a common underlying mental representation, yet also function on the basis of independent processing orientations (i.e., featural vs. holistic processing, respectively).
引用:
- Meissner,C. A.,&Brigham,J. C.(2001)。面部识别中的口头外部效应的荟萃分析。应用认知心理学,15,603-616。
- Meissner,C. A.,Sporer,S. L.,J.W.(2006)。作为目击者证据的人说明。在R. Lindsay,D. Ross,J. Read,&M.炸药(EDS。),眼神手册:人类的记忆。马瓦,新泽:劳伦斯·埃尔巴姆。
- Sporer,S. L.(1996)。描述其他人:心理问题。在S. L. Sporer,R. S. Malpass,&G. Koehnken(EDS),目击者识别的心理问题(第53-86页)。Hillsdale,NJ:Lawrence Erlbaum。