Doctoral Dissertation Research: An Investigation of Factors that Create and Mitigate Confirmation Bias in Judgments of Forensic Evidence

法医科学最近受到了批评，尤其是美国国家科学院，因为在已知的DNA免责案件中，法医科学错误的频率令人震惊。经验数据现在表明，确认偏差-即，倾向于以验证一个人先前存在的信念的方式来解释新的证据--会产生这样的错误。也就是说，法医检验员的客观性和准确性可能会受到他们对嫌疑人有罪或无罪的先验信念的影响。目前的研究将增强我们对加剧和减轻法医证据判断中确认偏差的因素的了解，希望指导改革，以尽量减少代价高昂的误判风险。在每项研究中，模拟法医将通过比较犯罪者和嫌疑人的笔迹样本来协助模拟刑事调查。研究1将测试是否模拟考官谁是导致相信嫌疑人是有罪的，因此将认为无罪的笔迹证据比那些谁不是有罪的。此外，研究1将探讨当笔迹样本高度相似和/或考官收到来自警方调查人员的模拟负面反馈时，这种偏见是否会加剧。研究2将提供第一个“证据排列”的实证检验，这是一种经常被提议作为对抗偏见的手段的程序性改革，但其效力仍然未知。在被引导期望嫌疑人有罪，无罪，或两者都没有，一些审查员将收到一个笔迹样本，每个犯罪者和嫌疑人-一种方法，有些人声称是固有的暗示有罪。剩下的审查员将使用“证据队列”，这迫使他们将三个不同的嫌疑人样本与犯罪者的样本进行比较，并指出哪一个（如果有的话）与之匹配。研究2将因此提供第一个经验数据，为长期以来关于证据队列潜在价值的争论提供信息。

The forensic sciences have recently been criticized, most notably by the National Academy of Sciences, due to the alarming frequency of forensic science errors in known DNA exoneration cases. Empirical data now suggests that confirmation bias -- i.e., the tendency to interpret new evidence in ways that validate one's pre-existing beliefs -- can produce such errors. That is to say, forensic examiners' objectivity and accuracy can be undermined by their a priori beliefs regarding a suspect's guilt or innocence. The current studies will enhance our knowledge of factors that exacerbate and mitigate confirmation biases in judgments of forensic evidence, in hopes of guiding reforms to minimize the risk of costly miscarriages of justice. In each study, mock forensic examiners will assist in a simulated criminal investigation by comparing handwriting samples from the perpetrator and suspect. Study 1 will test whether mock examiners who are led to believe that the suspect is guilty will consequently perceive exculpatory handwriting evidence as more incriminating than those who are not. In addition, Study 1 will explore whether this bias is exacerbated when the handwriting samples are highly similar and/or examiners receive simulated negative feedback from police investigators. Study 2 will provide the first empirical test of "evidence lineups," a procedural reform often proposed as a means of combating bias, but whose efficacy remains unknown. Having been led to expect the suspect's guilt, innocence, or neither, some examiners will receive one handwriting sample each from the perpetrator and suspect -- a method which some claim is inherently suggestive of guilt. The remaining examiners will utilize an "evidence lineup," which forces them to compare three different suspect samples against the perpetrator's sample and indicate which, if any, matches it. Study 2 will thus provide the first empirical data to inform the longstanding debate over the potential value of evidence lineups.