Assessing Cognitive Bias in Forensic Decisions: A Review and Outlook

In recent years, a number of studies have demonstrated that forensic examiners can be biased by task-irrelevant contextual information. However, concerns relating to methodological flaws and ecological validity attenuate how much the current body of knowledge can be applied to real-life operational settings. The current review takes a narrative approach to synthesizing the literature across forensic science. Further, the review considers three main issues: (i) primary research on contextual bias within forensic science; (ii) methodological criticisms of this research; (iii) an alternative perspective that task-irrelevant contextual information does not always lead to error. One suggestion for future research is outlined, which is that studies on contextual bias in forensic decisions should be conducted in collaboration between forensic scientists and cognitive psychologists. Only then can rigorous and ecological valid experiments be created that will be able to assess how task-irrelevant contextual information influences forensic analysis and judgments in operationally valid settings.     

Unpredictable Behavior Under the Influence of “Magic Mushrooms”: A Case Report and Review of the Literature

Fatalities implicating psychedelic mushrooms are not a common clinical situation in everyday forensic medicine. Despite classification as an illegal drug in many countries, psilocybin mushrooms have the reputation of being safe. We report the case of a young man who jumped from a second story balcony under the influence of psilocybin mushrooms. The psilocin assay was performed by gas chromatography coupled to an electron‐impact ionization time‐of‐flight detector (GC‐EI‐TOF) after solid‐phase extraction. Total psilocin was quantified in peripheral and cardiac blood as 60 and 67 ng/mL, respectively, and in urine (2230 ng/mL), bile (3102 ng/mL), and vitreous humor (57 ng/mL). This case report and review of literature highlights the danger of psilocybin mushrooms. Isolated use of psilocybin mushrooms by a regular consumer without psychiatric history, even under “safe” circumstances, can lead to a fatal outcome.     

Meta-analytically quantifying the reliability and biasability of forensic experts

Abstract:  In this paper we employ meta-analytic procedures and estimate effect sizes indexing the degree of reliability and biasability of forensic experts. The data are based on within-expert comparisons, whereby the same expert unknowingly makes judgments on the same data at different times. This allows us to take robust measurements and conduct analyses that compare variances within the same experts, and thus to carefully quantify the degree of consistency and objectivity that underlie expert performance and decision making. To achieve consistency, experts must be reliable, at least in the very basic sense that an expert makes the same decision when the same data are presented in the same circumstances, and thus be consistent with themselves. To achieve objectivity, experts must focus only on the data and ignore irrelevant information, and thus be unbiasable by extraneous context. The analyses show that experts are not totally reliable nor are they unbiasable. These findings are based on fingerprint experts decision making, but because this domain is so well established, they apply equally well (if not more) to all other less established forensic domains.     

The Utility of the Samworth and Gowland Age‐at‐Death “Look‐up” Tables in Forensic Anthropology*

Abstract: Accurate age‐at‐death estimates are crucial to forensic anthropologists when onstructing biological profiles aimed at narrowing a missing‐persons list and to allow for timely and efficient identification of an unknown victim. The present contribution evaluates the utility of three new age‐at‐death estimation techniques recently proposed by Samworth and Gowland (2007). Results indicate that, in the samples under study, the Samworth and Gowland estimates from the pubic symphysis and auricular surface perform similar to alternate phase methods. The combined method does not appear to further enhance either the precision or the accuracy of the single pubic symphysis age‐at‐death estimate. In conclusion, these new methods seem to be more robust to distribution deviations than originally proposed by Samworth and Gowland (2007). They are therefore suitable for immediate and reliable forensic usage in the United States and worthy of further research for their use in North American forensic contexts.     

Quality of Laypersons' Assessment of Forensically Relevant Stimuli,

The current study examined the potential for cognitive bias in lay examiners' comparisons of footwear impressions within the technical review process while addressing limitations of previous research. Prior research has found inconsistent results regarding the extent to which cognitive bias may influence forensic comparisons, often asking non-experts to review forensic stimuli above their competency level. Furthermore, past research has largely ignored the potential for cognitive bias during the technical review process. In collaboration with the Miami-Dade Police Department's Forensic Services Bureau, we examined the effects of previous examiners' level of experience and prior knowledge of the previous examiner's decision on the technical review stage of footwear impression stimuli. Before lay examiners were presented with pairs of known match and nonmatch footwear impressions, they were either told that an expert or a novice had previously examined them and determined them to be either a match, nonmatch, or inconclusive (plus a no-information condition). Participants then evaluated each pair of footwear impressions to make their own determinations of match, nonmatch, or inconclusive. Results support the technical review process for all decision types, as known nonmatch stimuli were generally more difficult for lay examiners to assess than known match stimuli. Knowledge of a prior examiner's decision and status was observed only when the prior decision was inconclusive, suggesting the need for inclusion of inconclusive decisions in future research examining cognitive bias in forensic examination.     

Forensic Approach to an Archaeological Casework of “Vampire” Skeletal Remains in Venice: Odontological and Anthropological Prospectus*

Abstract: During the years 2006–2007, the Archeological Superintendent of Veneto (Italy) promoted a research project on mass graves located on Nuovo Lazzaretto in Venice, where the corpses of plague deaths were buried during the 16th and 17th centuries. The burials were of different stages and are believed to be the remains of plague victims from the numerous outbreaks of pestilence, which occurred between the 15th and 17th centuries. Among the fragmented and commingled human bones, an unusual burial was found. The body was laid supine, with the top half of the thorax intact, arms parallel to the rachis axis, the articulations were anatomically unaltered. Both the skull morphology and the dimensions of the caput omeris suggest the body was a woman. A brick of moderate size was found inside the oral cavity, keeping the mandible wide open. The data collected by the anthropologist were used to generate a taphonomic profile, which precluded the positioning of the brick being accidental. Likewise, the probability of the brick having come from the surrounding burial sediment was rejected, as the only other inclusions found were bone fragments from previous burials in the same area. The data collected by the odontologist were employed for age estimation and radiological dental assessment. The forensic profile was based conceptually on the “circumstances of death” and concluded that the positioning of the brick was intentional, and attributed to a symbolic burial ritual. This ritual confirms the intimate belief held at those times, between the plague and the mythological character of the vampire.     

Forensic Paleontology: A Tool for “Intelligence” and Investigation

Paleontology and facies analysis proved to be useful tools in activities of intelligence and investigation on some criminal cases, as well as in in‐court activities, thus defining the “forensic paleontology” area of study. The definition was given by analyzing its possible specific applications and excluding some marginal activities. The reliability of forensic paleontology was then assessed in light of the results achieved in some actual cases and in an ad hoc simulation. The investigated cases concerned intelligence and ordinary law enforcement activities. Special attention was paid to crimes against the cultural heritage. Ex post re‐examination of the cases substantiated the value of this scientific branch in investigations, while stressing the possible difficulties in explaining its results to lay persons. Therefore, careful preparation of technical and linguistic preliminary notes for judges, prosecutors, and lawyers as well as a special training for consultants are recommended before presenting results as exhibits in in‐court cross‐examinations.     

Morphoscopic Trait Expression in “Hispanic” Populations

This study evaluates population variation of eight cranial morphoscopic traits using samples of known southwest Hispanics (n = 72), Guatemalans (n = 106), American Blacks (n = 146), and American Whites (n = 218). We applied the support vector machine (SVM) method to build a prediction model based on a subsample (20%) of the data; the remainder of the data was used as a test sample. The SVM approach effectively differentiated between the four groups with correct classification rates between 72% (Guatemalan group) and 94% (American Black group). However, when the Guatemalan and southwest Hispanic samples were pooled, the same model correctly classified all groups with a higher degree of accuracy (American Black = 96%; American White = 77%; and the pooled Hispanic sample = 91%). This study also identified significant differences between the two Hispanic groups in six of the eight traits using univariate statistical tests. These results speak to the unique population histories of these samples and the current use of the term “Hispanic” within forensic anthropology. Finally, we argue that the SVM can be used as a classification model for ancestry estimation in a forensic context and as a diagnostic tool may broaden the application of morphoscopic trait data for the assessment of ancestry.     

Root Morphology and Anatomical Patterns in Forensic Dental Identification: A Comparison of Computer‐Aided Identification with Traditional Forensic Dental Identification*

Abstract: An online forensic dental identification exercise was conducted involving 24 antemortem–postmortem (AM–PM) dental radiograph pairs from actual forensic identification cases. Images had been digitally cropped to remove coronal tooth structure and dental restorations. Volunteer forensic odontologists were passively recruited to compare the AM–PM dental radiographs online and conclude identification status using the guidelines for identification from the American Board of Forensic Odontology. The mean accuracy rate for identification was 86.0% (standard deviation 9.2%). The same radiograph pairs were compared using a digital imaging software algorithm, which generated a normalized coefficient of similarity for each pair. Twenty of the radiograph pairs generated a mean accuracy of 85.0%. Four of the pairs could not be used to generate a coefficient of similarity. Receiver operator curve and area under the curve statistical analysis confirmed good discrimination abilities of both methods (online exercise = 0.978; UT‐ID index = 0.923) and Spearman’s rank correlation coefficient analysis (0.683) indicated good correlation between the results of both methods. Computer‐aided dental identification allows for an objective comparison of AM–PM radiographs and can be a useful tool to support a forensic dental identification conclusion.     

Diagnosing Crime and Diagnosing Disease: Bias Reduction Strategies in the Forensic and Clinical Sciences

Cognitive effort is an essential part of both forensic and clinical decision‐making. Errors occur in both fields because the cognitive process is complex and prone to bias. We performed a selective review of full‐text English language literature on cognitive bias leading to diagnostic and forensic errors. Earlier work (1970–2000) concentrated on classifying and raising bias awareness. Recently (2000–2016), the emphasis has shifted toward strategies for “debiasing.” While the forensic sciences have focused on the control of misleading contextual cues, clinical debiasing efforts have relied on checklists and hypothetical scenarios. No single generally applicable and effective bias reduction strategy has emerged so far. Generalized attempts at bias elimination have not been particularly successful. It is time to shift focus to the study of errors within specific domains, and how to best communicate uncertainty in order to improve decision making on the part of both the expert and the trier‐of‐fact.     

The Value of Crime Scene and Site Visitation by Forensic Psychologists and Psychiatrists

Site visits and crime scene visitation by forensic psychologists and psychiatrists may enhance the accuracy and credibility of their forensic work in criminal, civil, and other important contexts. This ethically sound technique of after‐the‐fact data collection and verification offers numerous potential benefits to the forensic mental health professional: clarifying the subject's actions, assessing the reliability of witness reports, identifying contextual determinants of behavior, and more fully illuminating subject motivation and decision‐making. Limitations and suggested guidelines for conducting site visits are offered. Guidelines include preplanning, arranging for an informed guide to accompany and narrate the visit, and conducting the site visit prior to forensic examinations.     

Predicting Phenotype from Genotype: Normal Pigmentation*

Abstract: Genetic information in forensic studies is largely limited to CODIS data and the ability to match samples and assign them to an individual. However, there are circumstances, in which a given DNA sample does not match anyone in the CODIS database, and no other information about the donor is available. In this study, we determined 75 SNPs in 24 genes (previously implicated in human or animal pigmentation studies) for the analysis of single‐ and multi‐locus associations with hair, skin, and eye color in 789 individuals of various ethnic backgrounds. Using multiple linear regression modeling, five SNPs in five genes were found to account for large proportions of pigmentation variation in hair, skin, and eyes in our across‐population analyses. Thus, these models may be of predictive value to determine an individual’s pigmentation type from a forensic sample, independent of ethnic origin.     

Diagnosing Crime and Diagnosing Disease‐II: Visual Pattern Perception and Diagnostic Accuracy

Previously, we reviewed how general cognitive processes might be susceptible to bias across both forensic and clinical fields, and how interdisciplinary comparisons could reduce error. We discuss several examples of clinical tasks which are heavily dependent on visual processing, comparing them to eyewitness identification (EI). We review the “constructive” nature of visual processing, and how contextual factors influence both medical experts and witnesses in decision making and recall. Overall, studies suggest common cognitive factors uniting these visual tasks, in both their strengths and shortcomings. Recently forensic sciences have advocated reducing errors by identifying and controlling nonrelevant information. Such efforts could effectively assist medical diagnosis. We suggest potential remedies for cognitive bias in these tasks. These can generalize across the clinical and forensic domains, including controlling the sequencing of contextual factors. One solution is an agnostic primary reading before incorporation of a complete history and interpretation.     

Application of Postmortem 3D‐CT Facial Reconstruction for Personal Identification*

Abstract: Postmortem computed tomography (CT) images can show internal findings related to the cause of death, and it can be a useful method for forensic diagnosis. In this study, we scanned a ready‐made box by helical CT on 2‐mm slices in a mobile CT scanner and measured each side of the box to assess whether reconstructed images are useful for superimposition. The mean difference between the actual measurements and the measurements on the three‐dimensional (3D) reconstructed images (3D‐CT images) is 0.9 mm; we regarded it as having no effect on reconstruction for the superimposition method. Furthermore, we could get 3D‐CT images of the skull, which were consistent with the actual skull, indicating that CT images can be applied to superimposition for identification. This study suggested that postmortem CT images can be applied as superimpositions for unidentified cases, and thinner slices or cone beam CT can be a more precise tool.     

Human Factors Effecting Forensic Decision Making: Workplace Stress and Well‐being

Over the past decade, there has been a growing openness about the importance of human factors in forensic work. However, most of it focused on cognitive bias, and neglected issues of workplace wellness and stress. Forensic scientists work in a dynamic environment that includes common workplace pressures such as workload volume, tight deadlines, lack of advancement, number of working hours, low salary, technology distractions, and fluctuating priorities. However, in addition, forensic scientists also encounter a number of industry‐specific pressures, such as technique criticism, repeated exposure to crime scenes or horrific case details, access to funding, working in an adversarial legal system, and zero tolerance for “errors”. Thus, stress is an important human factor to mitigate for overall error management, productivity and decision quality (not to mention the well‐being of the examiners themselves). Techniques such as mindfulness can become powerful tools to enhance work and decision quality.     

Optical Characterization of Some Modern “Eco‐Friendly” Fibers*

Abstract: Fibers that are termed “eco‐friendly” or “biodegradable” by manufacturers are increasingly being used in textile products such as apparel and carpeting to appeal to the ever more environmentally aware public. As such, these modern fibers are expected to begin showing up more often in forensic casework, and it is important that the forensic examiner recognize them. This study employed polarized light microscopy (PLM) and Fourier transform infrared (FTIR) microspectroscopy to characterize selected fibers of azlon, polylactic acid (PLA), cellulose composites of alginate or chitin, and bamboo (viscose rayon). Fiber cross‐sections, refractive indices, melting points, solubilities, and FTIR measurements were conducted. Results indicate that the azlons and PLA fibers are easily distinguishable from other textile fibers by their optical and chemical properties. The cellulose composites show only small differences in comparison with other cellulose‐based fibers, while bamboo viscose rayon is indistinguishable from normal viscose rayon.     

试论我国司法鉴定回避制度的完善

司法鉴定回避制度是确保鉴定公正的重要制度.司法鉴定回避制度应当具备适应现实所需的开放的特性.现行关于鉴定回避的立法条文存在文本性缺陷.需要根据实践情况,在构建公正和高效的指导原则下,规范鉴定回避的情形和程序,以促进鉴定回避制度的完善.     

The Odontology Victim Identification Skill Assessment System*,†

Abstract: Mass fatality identification efforts involving forensic odontology can involve hundreds of dental volunteers. A literature review was conducted and forensic odontologists and dental educators consulted to identify lessons learned from past mass fatality identification efforts. As a result, the authors propose a skill assessment system, the Odontology Victim Identification Skill Assessment System (OVID‐SAS), which details qualifications required to participate on the Antemortem, Postmortem, Ante/Postmortem Comparison, Field, and Shift Leader/Initial Response Teams. For each qualification, specific skills have been identified along with suggested educational pedagogy and skill assessment methods. Courses and assessments can be developed by dental schools, professional associations, or forensic organizations to teach and test for the skills required for dental volunteers to participate on each team. By implementing a system, such as OVID‐SAS, forensic odontologists responsible for organizing and managing a forensic odontology mass fatality identification effort will be able to optimally utilize individuals presenting with proven skills.     

The Power of Contextual Effects in Forensic Anthropology: A Study of Biasability in the Visual Interpretations of Trauma Analysis on Skeletal Remains

The potential for contextual information to bias assessments in the forensic sciences has been demonstrated, in several forensic disiplines. In this paper, biasability potential within forensic anthropology was examined by analyzing the effects of external manipulations on judgments and decision‐making in visual trauma assessment. Three separate websites were created containing fourteen identical images. Participants were randomly assigned to one website. Each website provided different contextual information, to assess variation of interpretation of the same images between contexts. The results indicated a higher scoring of trauma identification responses for the Mass grave context. Furthermore, a significant biasing effect was detected in the interpretation of four images. Less experienced participants were more likely to indicate presence of trauma. This research demonstrates bias impact in forensic anthropological trauma assessments and highlights the importance of recognizing and limiting cognitive vulnerabilities that forensic anthropologists might bring to the analysis.     

Failings of Trauma‐Specific and Related Psychological Tests in Detecting Post‐Traumatic Stress Disorder in Forensic Settings

Judges and juries tend to be particularly impressed by test data, especially quantitative test data. Psychometric tests specific for assessing the presence of post‐traumatic stress disorder (PTSD) are commonly employed by forensic mental health evaluators. Most of these instruments, however, have been designed to detect PTSD in treatment or research, and not forensic, settings. Those who rely on these measures without adequate awareness of their often significant limits in correctly identifying malingering may induce finders of fact to inordinately confidently accept the presence of PTSD. This article reviews problematic structural and content components of trauma‐specific and related instruments used to evaluate PTSD and discusses the utility of specific techniques liable to be used in forensic settings to “fool” these measures.