Ling Shichun, Kaplan Jacob, Berryessa Colleen M
California State University, Los Angeles, United States.
University of Pennsylvania, United States.
Sci Justice. 2021 Mar;61(2):142-149. doi: 10.1016/j.scijus.2020.11.004. Epub 2020 Nov 18.
Recent studies have found that the general public perceives forensic evidence to be relatively inaccurate and to involve high levels of human judgement. This study examines how important the general public finds forensic evidence by comparing decisions on guilt and punishment in criminal cases that involve forensic versus eyewitness testimony evidence and examining whether a CSI effect exists. Specifically, this experimental survey study utilized a 2 (crime type: murder or rape) × 4 (evidence type: DNA, fingerprint, victim eyewitness testimony, or bystander eyewitness testimony) - 1 (no victim testimony for murder scenario) design, yielding seven vignettes scenarios to which participants were randomly assigned. Results indicate that forensic evidence was associated with more guilty verdicts and higher confidence in a guilty verdict. Forensic evidence did not change the expected sentence length and did not generally affect the ideal sentence length. However, for rape, respondents believed that the defendant should receive a longer sentence when forensic evidence was presented but forensic evidence did not alter likely sentence that respondents expected the defendant to receive. The results of this study did not support a CSI effect. Overall, this study suggests that forensic evidence - particularly DNA - has a stronger influence during the verdict stage than the sentencing stage.
最近的研究发现，普通公众认为法医证据相对不准确，且涉及高水平的人为判断。本研究通过比较涉及法医证据与目击证人证言证据的刑事案件中的有罪判决和量刑决定，并考察是否存在“犯罪现场调查效应”，来探究普通公众认为法医证据有多重要。具体而言，这项实验性调查研究采用了2（犯罪类型：谋杀或强奸）×4（证据类型：DNA、指纹、受害者目击证人证言或旁观者目击证人证言）-1（谋杀场景无受害者证言）的设计，产生了七个小场景，参与者被随机分配到这些场景中。结果表明，法医证据与更多的有罪判决以及对有罪判决更高的信心相关。法医证据并未改变预期刑期长度，也通常不影响理想刑期长度。然而，对于强奸案，当出示法医证据时，受访者认为被告应被判处更长刑期，但法医证据并未改变受访者预期被告会被判处的可能刑期。本研究结果不支持“犯罪现场调查效应”。总体而言，本研究表明，法医证据——尤其是DNA——在判决阶段比量刑阶段有更强的影响力。
