Garrett Brandon L, Crozier William E, Grady Rebecca
School of Law, Duke University, 210 Science Drive, Durham, NC.
Department of Psychological Science and Department of Criminology, Law & Society, University of California-Irvine, 2340 Social Ecology II, Irvine, 92617, CA.
J Forensic Sci. 2020 Jul;65(4):1199-1209. doi: 10.1111/1556-4029.14323. Epub 2020 Apr 22.
Forensic examiners regularly testify in criminal cases, informing the jurors whether crime scene evidence likely came from a source. In this study, we examine the impact of providing jurors with testimony further qualified by error rates and likelihood ratios, for expert testimony concerning two forensic disciplines: commonly used fingerprint comparison evidence and a novel technique involving voice comparison. Our method involved surveying mock jurors in Amazon Mechanical Turk (N = 897 laypeople) using written testimony and judicial instructions. Participants were more skeptical of voice analysis and generated fewer "guilty" decisions than for fingerprint analysis (B = 2.00, OR = 7.06, p = <0.000). We found that error rate information most strongly decreased "guilty" votes relative to no qualifying information for participants who heard fingerprint evidence (but not those that heard voice analysis evidence; B = -1.16, OR = 0.32, p = 0.007). We also found that error rates and conclusion types led to a greater decrease on "guilty" votes for fingerprint evidence than voice evidence (B = 1.44, OR = 4.23, p = 0.021). We conclude that these results suggest jurors adjust the weight placed on forensic evidence depending on their prior views about its reliability. Future research should develop testimony and judicial instructions that can better inform jurors of the strengths and limitations of forensic evidence.
法医鉴定人员经常在刑事案件中作证，告知陪审员犯罪现场证据是否可能来自某个源头。在本研究中，我们考察了向陪审员提供经错误率和似然比进一步限定的证词所产生的影响，这些证词涉及两种法医鉴定学科的专家证词：常用的指纹比对证据和一种涉及语音比对的新技术。我们的方法是在亚马逊土耳其机器人平台上对模拟陪审员（N = 897名普通民众）进行书面证词和司法指示的调查。与指纹分析相比，参与者对语音分析持更怀疑态度，做出“有罪”裁决的人数更少（B = 2.00，OR = 7.06，p = <0.000）。我们发现，对于听到指纹证据的参与者（但听到语音分析证据的参与者并非如此），与没有限定信息相比，错误率信息最显著地减少了“有罪”投票（B = -1.16，OR = 0.32，p = 0.007）。我们还发现，与语音证据相比，错误率和结论类型导致指纹证据的“有罪”投票减少得更多（B = 1.44，OR = 4.23，p = 0.021）。我们得出结论，这些结果表明陪审员会根据他们对法医证据可靠性的先入之见来调整对其的重视程度。未来的研究应该制定能够更好地让陪审员了解法医证据优缺点的证词和司法指示。
