DNA Examiners: Judgment and Influence

DNA分析被广泛认为可以在法律案件中提供客观准确的证据。但是，像其他法医方法一样，DNA分析需要人类的判断。这种判断可能受到非法医背景信息的影响。一个重要但尚未研究的问题是，DNA鉴定人关于如何检测一个物体的DNA的决定是否取决于背景线索，比如警方调查人员的评论。如果是这样，这就提出了以下问题：(a)这些线索是否会影响鉴定人是否在物体上发现DNA， (b)鉴定人如何应对与他们所做的测试选择有关的挑战，以及(c)陪审员如何在这些挑战之后权衡DNA证据。本研究包括两个对照实验研究。在研究1中，100名经验丰富的DNA鉴定员将从一个模拟的刑事案件中获得材料，在这个案件中，他们对DNA证据可能存在于物体上的位置的预期是通过上下文线索来操纵的。然后，检查人员将进行DNA分析并得出结论。接下来，主考官将回答类似交叉考试的问题，挑战他们的测试决定和结论。研究2考察了模拟陪审员对案件的判断和决定如何受到(a) DNA鉴定人交叉检验中提出的论点的复杂性，以及(b)鉴定人对这些论点的反应的影响。本研究对刑事司法系统、法医学实践和心理学理论的发展具有重要意义。刑事司法系统从识别并纠正可能干扰法医决策的因素中受益。这些改进可能会进入法医科学培训项目和协议，有助于定罪，释放无辜者。这项研究还通过深入了解认知和动机偏差如何以及何时在复杂的、多阶段的、多人的决策任务中起作用，推进了心理学理论。

DNA analysis is widely believed to offer objective and accurate evidence in legal cases. But, like other forensic methods, DNA analysis requires human judgment. Such judgment may be influenced by non-forensic contextual information. An important and as yet unstudied issue is whether a DNA examiner's decision about how to test an object for DNA depends on contextual cues such as comments made by police investigators. If so, this raises questions about (a) whether such cues can affect whether an examiner finds DNA on an object, (b) how examiners respond to challenges pertaining to the testing choices they make, and (c) how jurors weigh DNA evidence following such challenges. This research includes two controlled experimental studies. In Study 1, one hundred experienced DNA examiners will receive materials from a simulated criminal case in which their expectations about where DNA evidence likely exists on an object is manipulated via contextual cues. The examiners will then perform a DNA analysis and provide conclusions. Next, the examiners' will respond to cross-exam-like questions that challenge their testing decisions and conclusions. Study 2 examines how mock jurors' judgments and decisions about a case are affected by (a) the complexity of arguments raised on the DNA examiner's cross-exam, and (b) the examiner's response to those arguments.This research has significant implications for the criminal justice system, for the practice of forensic science, and for the advancement of psychological theory. The criminal justice system benefits from identifying, and then correcting for, factors that can interfere with forensic decision-making. These improvements, which may find their way into forensic science training programs and protocols, can help convict the guilty and free the innocent. This research also advances psychological theory by providing insight into how and when cognitive and motivational biases operate in a complex, multi-stage, multi-person decision task.