Perceived infallibility of detection dog evidence: implications for juror decision-making

This study focuses on the trust that potential jurors have in unsubstantiated evidence and the implications of such trust for legal decision-making. We examined whether participants’ motivation to think deeply (‘need for cognition,’ NC) and belief in science moderated their trust in potentially fallible detection dog evidence when selecting a verdict in a trial scenario. A detection dog twice indicated the presence of drugs in the scenario, yet no drugs were actually found. Those who chose a guilty verdict without drugs present featured stronger beliefs in detection dog evidence. They were also more confident that a dog alert indicated the presence of drugs, even though the scientific literature actually shows that detection dog evidence is subject to biases and other challenges to reliability. Our findings indicate that an unsubstantiated belief and trust in detection dog evidence may negatively influence juror decision-making, which may, in turn, pose consequences for fairness and justice. Participants believed that detection dogs provide powerful and reliable evidence, and these beliefs were clearly associated with stronger beliefs in science. These findings, therefore, raise serious concerns about jurors’ indiscriminate trust in forensic evidence, be it detection dog evidence or other lines of evidence presented in court.     

Identifying and measuring juror pre-trial bias for forensic evidence: development and validation of the Forensic Evidence Evaluation Bias Scale

Abstract

Previous research has provided support for the impact of juror pre-trial bias on judicial decision making, particularly in cases where the evidence presented at trial is of weak or ambiguous probative value. In an effort to identify whether a pre-trial bias for forensic evidence exists, the Forensic Evidence Evaluation Bias Scale (FEEBS) was developed and tested. The results of a principal components analysis suggested that two distinct constructs were being measured, corresponding to a pro-prosecution and pro-defence bias toward forensic evidence. In a second validation study, scores on these two subscales were compared with other existing juror bias measures (Juror Bias Scale and Belief in a Just World) and in a mock juror decision making task only the pro-prosecution subscale of the FEEBS predicted the perceived strength of forensic evidence. A partial mediation model is presented which explains the relationship between this bias and verdict preferences. The implications of this potential juror bias are discussed in the context of real juries, the CSI Effect (which refers to anecdotal claims that jurors are biased by the popularity of fictional representations of forensic science on television) and peremptory challenges, as well as future research directions.     

Understanding juror perceptions of forensic evidence: investigating the impact of case context on perceptions of forensic evidence strength

The most widely accepted model of juror decision making acknowledges the importance of both the case-specific information presented in the courtroom, as well as the prior general knowledge and beliefs held by each juror. The studies presented in this paper investigated whether mock jurors could differentiate between evidence of varying strengths in the absence of case information and then followed on to determine the influence that case context (and therefore the story model) has on judgments made about the strength of forensic DNA evidence. The results illustrated that mock jurors correctly identified various strengths of evidence when it was not presented with case information; however, the perceived strength of evidence was significantly inflated when presented in the context of a criminal case, particularly when the evidence was of a weak or ambiguous standard. These findings are discussed in relation to the story model, and the potential implications for real juries.     

How Cross‐Examination on Subjectivity and Bias Affects Jurors’ Evaluations of Forensic Science Evidence

Contextual bias has been widely discussed as a possible problem in forensic science. The trial simulation experiment reported here examined reactions of jurors at a county courthouse to cross‐examination and arguments about contextual bias in a hypothetical case. We varied whether the key prosecution witness (a forensic odontologist) was cross‐examined about the subjectivity of his interpretations and about his exposure to potentially biasing task‐irrelevant information. Jurors found the expert less credible and were less likely to convict when the expert admitted that his interpretation rested on subjective judgment, and when he admitted having been exposed to potentially biasing task‐irrelevant contextual information (relative to when these issues were not raised by the lawyers). The findings suggest, however, that forensic scientists can immunize themselves against such challenges and maximize the weight jurors give their evidence by adopting context management procedures that blind them to task‐irrelevant information.     

“CSI效应”对香港华人群体的科学证据感知评估

电视是向公众传递信息的强大媒介。最近,法庭科学和刑事司法相关题材内容在各种媒体激增,伴随着公众对法庭证据的期望提高,"CSI效应"(犯罪现场调查影视剧效应)应运而生。本研究对CSI效应的探讨有两个方面的贡献。第一,验证了在香港中国人群中是否存在CSI效应。第二,采用模拟陪审团模式,从实证角度出发全面考察CSI效应。研究发现,尽管涉及法庭科学证据的媒体报道数量确实在某种程度上影响了参与者对法庭证据的感知,但这种感知并不影响参与者对法律的判断。法庭科学题材影视剧的观众在控方仅出示法庭证据时不可能判定被告有罪,在仅出示证词时也不可能判定被告有罪。当提交法庭证据时,唯一判定被告有罪的重要预测因素是参与者对科学证据可靠性的评价。本研究的结果表明在香港不存在CSI效应。     

Swedish crime scene technicians: facilitations,epistemic frictions and professionalization from the outside

ABSTRACT

This article investigates the role of crime scene technicians in the Swedish criminal justice system, and particularly how Swedish crime scene technicians not only examine crime scenes but also facilitate the criminal justice system’s joint production of forensic evidence. It proposes thinking about the criminal justice system as a conglomeration of epistemic cultures, that is, of communities with different ways of producing and understanding forensic evidence. Such a perspective makes it possible to understand interprofessional frictions as epistemic frictions as well as to draw attention to the facilitations, mediations and translations that crime scene technicians perform. This perspective also makes it possible to illuminate how the crime scene technicians’ professionalization – a professionalization from the outside – affects both their future crime scene work and their facilitations.     

Educating Jurors about Forensic Evidence: Using an Expert Witness and Judicial Instructions to Mitigate the Impact of Invalid Forensic Science Testimony

Invalid expert witness testimony that overstated the precision and accuracy of forensic science procedures has been highlighted as a common factor in many wrongful conviction cases. This study assessed the ability of an opposing expert witness and judicial instructions to mitigate the impact of invalid forensic science testimony. Participants (N = 155) acted as mock jurors in a sexual assault trial that contained both invalid forensic testimony regarding hair comparison evidence, and countering testimony from either a defense expert witness or judicial instructions. Results showed that the defense expert witness was successful in educating jurors regarding limitations in the initial expert's conclusions, leading to a greater number of not-guilty verdicts. The judicial instructions were shown to have no impact on verdict decisions. These findings suggest that providing opposing expert witnesses may be an effective safeguard against invalid forensic testimony in criminal trials.     

美国法庭科学证据的应用与发展

＂法庭科学＂萌芽于古代中国,兴盛于近现代西方国家,最终发展成为具备完整科学体系的现代意义上的法庭科学学科。法庭科学证据的应用与发展显然与法庭科学的发展与应用密切相关,它们相互制约,相互促进。美国司法制度中关于法庭科学证据的证明力、可信度、可采性的分立质疑对法庭科学本身的发展无疑起到鞭策与促进作用。美国法庭科学证据的司法制度以及常用的一些传统与高技术法庭科学证据的使用过程中存在的许多问题,理解法庭科学证据标准,对我国法庭科学及其证据的研究与应用有所启迪。     

Public beliefs about the accuracy and importance of forensic evidence in the United States

Recent advances in forensic science, especially the use of DNA technology, have revealed that faulty forensic analyses may have contributed to miscarriages of justice. In this study we build on recent research on the general public’s perceptions of the accuracy of 10 forensic science techniques and of each stage in the investigation process. We find that individuals in the United States hold a pessimistic view of the forensic science investigation process, believing that an error can occur about half of the time at each stage of the process. We find that respondents believe that forensics are far from perfect, with accuracy rates ranging from a low of 55% for voice analysis to a high of 83% for DNA analysis, with most techniques being considered between 65% and 75% accurate. Nevertheless, respondents still believe that forensic evidence is a key part of a criminal case, with nearly 30% of respondents believing that the absence of forensic evidence is sufficient for a prosecutor to drop the case and nearly 40% believing that the presence of forensic evidence – even if other forms of evidence suggest that the defendant is not guilty – is enough to convict the defendant.     

Validation of the factor structure and predictive validity of the Forensic Evidence Evaluation Bias Scale for robbery and sexual assault trial scenarios

In order to investigate the role of pre-trial attitudes about forensic science in juror decision-making, a previous study demonstrated the predictive validity of the Forensic Evidence Evaluation Bias Scale (FEEBS), using a murder trial scenario, which featured ambiguous prosecution DNA evidence. The current study validates the FEEBS using two new crime types and the conditions include a manipulation of the presence of DNA evidence in the trial scenario. The FEEBS successfully predicted mock jurors' perceptions of the probative value of DNA evidence for both robbery and sexual assault trials. The two subscales of the FEEBS were demonstrated to have different predictive ability depending on the presence or absence of DNA evidence. A confirmatory factor analytic technique was used to validate the underlying two-factor structure of the FEEBS, as previously proposed. These results are discussed with reference to the CSI Effect literature, and the potential for improvement to less empirically supported voir dire questioning techniques.     

The CSI Effect and the impact of DNA evidence on mock jurors and jury deliberations

ABSTRACT

The present research examined the CSI Effect and the impact of DNA evidence on mock jurors and jury deliberations using a 3 (Crime Drama Viewing: low, moderate, high)?×?3 (Evidence: DNA innocent, DNA guilty, no DNA control) design. A sample of 178 jury-eligible college students read a case of breaking and entering. Pre-deliberation, some support for a CSI Effect was found with high viewers’ extent of guilt ratings significantly lower than moderate and low viewers’ in the no DNA control and the DNA innocent conditions. This effect was not present for verdicts. Contrary to a CSI Effect, crime drama viewing was not related to guilt judgments with incriminating DNA evidence. A content analysis of comments made during deliberations found little support for the CSI Effect entering the jury room. Specifically, CSI Effect predictions were not supported when examining the discussion of DNA evidence, expressing DNA opinions, or mentioning missing evidence. Overall, the limited CSI Effect found for individuals was attenuated during deliberation. The alarm raised over a possible CSI Effect influencing jury decision making may be unwarranted.     

Error Rates,Likelihood Ratios,and Jury Evaluation of Forensic Evidence

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.     

The effectiveness of forensic evidence in the investigation of volume crime scenes

This study investigates the effectiveness of forensic evidence in UK volume crime investigations. The main aim was to identify characteristics of forensic evidence that influence its effectiveness in converting detections into criminal charges, as well as to critically consider the effectiveness of a recent service level agreement (SLA) implemented by Wiltshire Police, which aimed at reducing CSI attendance. The sample consisted of 445 police recorded cases received from Wiltshire Police. Presence or absence and location-related characteristics of fingerprint, DNA, and footwear evidence were evaluated on the effectiveness of forensic evidence and examined within the contexts of different volume crimes. Results showed a high level of correlation in converting detections into criminal charges where the presence of DNA, footwear, and multiple evidence types was recorded; and a positive correlation between forensic evidence ineffectiveness and presence of fingerprints, particularly in residential burglaries. Differences between individual offence types were expressed. The most prominent feature influencing the effectiveness of forensic evidence was found to be related to the movability of the exhibit associated with the recovered evidence, with DNA recovered from non-movable items presenting the strongest effectiveness. Cases processed after the implementation of the SLA did not show significant differences in forensic evidence effectiveness as compared to cases processed prior to the SLA, however, they demonstrated a lack in effectiveness of DNA evidence. The findings of the current research provide a better understanding of the contextual influences on the potential of forensic evidence and can support improvement of crime scene screening and CSI resource deployment.     

Community Members’ Perceptions of the CSI Effect

The CSI Effect is the notion that crime show viewing influences jurors to have unrealistic expectations of forensic evidence, which then affects their trial decisions. Analyses of popular media shows that the media portrays the effect as a real problem, and research surveying the legal community indicates that they believe the CSI Effect exists and may change their investigation and trial strategies accordingly. The present study expanded on this research by surveying community members regarding their perceptions of the CSI Effect. Community members reported their general television and crime show viewing behaviors, and we examined this in relation to their knowledge construction of the CSI Effect. Findings indicate that overall, the majority of community members did not have knowledge of the CSI effect, but those who did perceive it as an unrealistic expectation of evidence. When provided with a definition of the CSI Effect, people generally believed it exists. Additionally, crime show viewing and participant’s race influenced people’s perceptions of the CSI effect. Limitations of this study and directions for future research are also discussed.     

An Evidence‐based Forensic Taxonomy of Windows Phone Dating Apps

Advances in technologies including development of smartphone features have contributed to the growth of mobile applications, including dating apps. However, online dating services can be misused. To support law enforcement investigations, a forensic taxonomy that provides a systematic classification of forensic artifacts from Windows Phone 8 (WP8) dating apps is presented in this study. The taxonomy has three categories, namely: Apps Categories, Artifacts Categories, and Data Partition Categories. This taxonomy is built based on the findings from a case study of 28 mobile dating apps, using mobile forensic tools. The dating app taxonomy can be used to inform future studies of dating and related apps, such as those from Android and iOS platforms.     

Impact of hypnotic testimony on the jury

In the past decade, the forensic use of hypnosis to enhance the memories of victims, witnesses, and defendants has sharply increased. A great deal of controversy surrounds this issue. Some commentators argue that testimony derived from hypnosis should not be allowed as evidence because of its inherent unreliability and the unduly powerful impact it may have on a jury. In the present research, we used a jury simulation technique to study the impact that a hypnotically refreshed witness has upon jurors' decision making. A major finding is that jurors view hypnotic testimony with a certain amount of skepticism. In some respects, its impact is comparable to that of testimony based on delayed recall, and rarely does it have the impact of testimony from an immediate report. In addition, jurors' judgments about hypnotically refreshed testimony affected the way they evaluated other evidence at trial: Jurors who learned that a prosecution witness had been hypnotized were less believing ofother prosecution witnesses than were jurors not exposed to hypnotic testimony. The forensic application of these findings is discussed.This research was supported by a grant from the National Science Foundation, Law and Social Sciences Program. We thank Jane Goodman, Doug Leber, Bonnie Sawnson, Russ Wade, Karen Guest, Jonna Barsanti, Don Kline, Elaine Sullivan, and David Kuykendall for their help at various stages of the project.     

论专家辅助人意见——以刑事辩护为视角的分析

我国2012年新《刑事诉讼法》首次设立专家辅助人制度，对鉴定意见的质证提供了技术上的支持，对于刑事辩护来说意义重大。从证据法的角度看来，专家辅助人意见具有言词证据、意见证据、弹劾证据的多重属性，因此意见的内容应围绕鉴定意见中的专门性问题，并结合《刑事诉讼法》及相关司法解释对鉴定意见的审查判断规则来提出；而法庭对于鉴定意见的审查也应从准入资格与可靠性两方面进行，以免专家辅助人意见替代鉴定意见来主导审判。     

Forensic Evidence in Homicide Investigations and Prosecutions

Even though forensic evidence is collected at virtually every homicide scene, only a few studies have examined its role in investigation and prosecution. This article adds to the literature by providing the results of a study of 294 homicide cases (315 victims) occurring in Cleveland, Ohio, between 2008 and 2011. Through a logistic regression on open versus closed cases, the collection of knives, administration of gunshot residue (GSR) kits, and clothing at the scene were positively and significantly related to case closures, while collection of ballistics evidence and DNA evidence were statistically significant in the opposite direction. With regard to analysis, the clearance rate for cases with probative results (i.e., matches or exclusions) was 63.1% compared to a closure rate of 56.3% for cases without probative results. However, only 23 cases had probative results prior to arrest compared to 128 cases with probative results after arrest.