Cascading Bias of Initial Exposure to Information at the Crime Scene to the Subsequent Evaluation of Skeletal Remains,

Thirty‐eight participants took part in a study that investigated the potential cascading effects of initial exposure to extraneous context upon subsequent decision‐making. Participants investigated a mock crime scene, which included the excavation of clandestine burials that had a male skeletal cast dressed either in female or gender neutral clothing. This was followed by a forensic anthropological assessment of the skeletal remains, with a control group assessing the same male skeletal cast without any clothing context. The results indicated that the sex assessment was highly dependent upon the context in which participants were exposed to prior to the analysis. This was especially noticeable in the female clothing context where only one participant determined the male skeletal cast to be male. The results demonstrate the importance of understanding the role of context in forensic anthropology at an early stage of an investigation and its potential cascading effect on subsequent assessments.     

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.     

Cognitive bias in forensic anthropology: Visual assessment of skeletal remains is susceptible to confirmation bias

An experimental study was designed to examine cognitive biases within forensic anthropological non-metric methods in assessing sex, ancestry and age at death. To investigate examiner interpretation, forty-one non-novice participants were semi randomly divided into three groups. Prior to conducting the assessment of the skeletal remains, two of the groups were given different extraneous contextual information regarding the sex, ancestry and age at death of the individual. The third group acted as a control group with no extraneous contextual information. The experiment was designed to investigate if the interpretation and conclusions of the skeletal remains would differ amongst participants within the three groups, and to assess whether the examiners would confirm or disagree with the given extraneous context when establishing a biological profile. The results revealed a significant biasing effect within the three groups, demonstrating a strong confirmation bias in the assessment of sex, ancestry and age at death. In assessment of sex, 31% of the participants in the control group concluded that the skeleton remains were male. In contrast, in the group that received contextual information that the remains were male, 72% concluded that the remains were male, and in the participant group where the context was that the remains were of a female, 0% of the participants concluded that the remains were male. Comparable results showing bias were found in assessing ancestry and age at death. These data demonstrate that cognitive bias can impact forensic anthropological non-metric methods on skeletal remains and affects the interpretation and conclusions of the forensic scientists. This empirical study is a step in establishing an evidence base approach for dealing with cognitive issues in forensic anthropological assessments, so as to enhance this valuable forensic science discipline.     

Canid scavenging/disarticulation sequence of human remains in the Pacific Northwest

Greater understanding of animal scavenging of human remains can assist forensic science investigators in locating and recovering dispersed skeletal elements, in recognizing damage produced by scavengers, and in making more informed estimates of the postmortem interval. The pattern of skeletal damage can indicate whether the body was scavenged while intact or at some time after other natural processes of disarticulation had begun. This study analyzed thirty partially to fully skeletonized human remains with respect to scavenging at the time of body discovery in order to determine if a patterned consumption sequence existed. The scavengers were primarily coyotes (Canis latrans) and domestic dogs (C. familiaris). Sixteen non-carnivore-scavenged remains were also examined and contrasted with the carnivore-scavenged sample. Observed postmortem intervals from death to recovery ranged from 4 h to 52 months. Results demonstrate that canid scavenging of human remains takes place in sequential stages: Stage 0 = no bony involvement; Stage 1 = ventral thorax damaged and one or both extremities removed; Stage 2 = lower extremity involvement; Stage 3 = only vertebral segments remain articulated; and Stage 4 = total disarticulation. Results revealed a clear correspondence between stages of disarticulation and the postmortem interval.     

Discriminant function analysis for sex assessment in pelvic girdle bones: sample from the contemporary Mexican population

Sex assessment of skeletal remains plays an important role in forensic anthropology. The pelvic bones are the most studied part of the postcranial skeleton for the assessment of sex. It is evident that a population-specific approach improves rates of accuracy within the group. The present study proposes a discriminant function method for the sex assessment of skeletal remains from a contemporary Mexican population. A total of 146 adult human pelvic bones (61 females and 85 males) from the skeletal series pertaining to the National Autonomous University of Mexico were evaluated. Twenty-four direct metrical parameters of coxal and sacral bones were measured and subsequently, sides and sex differences were evaluated, applying a stepwise discriminant function analysis. Coxal and sacra functions achieved accuracies of 99% and 87%, respectively. These analyses follow a population-specific approach; nevertheless, we consider that our results are applicable to any other Hispanic samples for purposes of forensic human identification.     

Stature estimation from fragmentary femora: a revision of the Steele method

The skeletal remains presented to forensic anthropologists are often fragmentary. Previously described methods of estimating stature from segments of long bones have not proved satisfactory because of the difficulty involved in identifying the precise anatomical landmarks by which they are defined. This study represents an assessment of the feasibility of stature estimation from fragmentary femora. A sample of 200 males and females, blacks and whites (total sample = 800), was obtained from the Terry Collection. New regression equations for the estimation of maximum femur length and stature from three well-defined and easy-to-measure segments of the femur are presented. This technique represents an improvement over methods currently in use for estimating stature from femur fragments; the location of the anatomical landmarks and the accuracy of the prediction are enhanced. The applicability of these formulae to a modern forensic sample is addressed with regard to secular trends in stature increase and changes in body segment proportions.     

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.     

A forensic science perspective on the role of images in crime investigation and reconstruction

This article presents a global vision of images in forensic science. The proliferation of perspectives on the use of images throughout criminal investigations and the increasing demand for research on this topic seem to demand a forensic science-based analysis. In this study, the definitions of and concepts related to material traces are revisited and applied to images, and a structured approach is used to persuade the scientific community to extend and improve the use of images as traces in criminal investigations. Current research efforts focus on technical issues and evidence assessment. This article provides a sound foundation for rationalising and explaining the processes involved in the production of clues from trace images. For example, the mechanisms through which these visual traces become clues of presence or action are described. An extensive literature review of forensic image analysis emphasises the existing guidelines and knowledge available for answering investigative questions (who, what, where, when and how). However, complementary developments are still necessary to demystify many aspects of image analysis in forensic science, including how to review and select images or use them to reconstruct an event or assist intelligence efforts. The hypothetico-deductive reasoning pathway used to discover unknown elements of an event or crime can also help scientists understand the underlying processes involved in their decision making. An analysis of a single image in an investigative or probative context is used to demonstrate the highly informative potential of images as traces and/or clues. Research efforts should be directed toward formalising the extraction and combination of clues from images. An appropriate methodology is key to expanding the use of images in forensic science.     

The Influence of Actuarial Risk Assessment in Clinical Judgments and Tribunal Decisions about Mentally Disordered Offenders in Maximum Security

Research has shown that actuarial assessments of violence risk are consistently more accurate than unaided judgments by clinicians, and it has been suggested that the availability of actuarial instruments will improve forensic decision making. This study examined clinical judgments and autonomous review tribunal decisions to detain forensic patients in maximum security. Variables included the availability of an actuarial risk report at the time of decision making, patient characteristics and history, and clinical presentation over the previous year. Detained and transferred patients did not differ in their actuarial risk of violent recidivism. The best predictor of tribunal decision was the senior clinician's testimony. There was also no significant association between the actuarial risk score and clinicians' opinions. Whether the actuarial report was available at the time of decision making did not alter the statistical model of either clinical judgments or tribunal decisions. Implications for the use of actuarial risk assessment in forensic decision making are discussed.     

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.     

A Method for Estimating Sex Using Metric Analysis of the Scapula*

Abstract: The most accurate and precise methods for the assessment of age and stature often require knowledge of sex. Thus, being able to correctly identify sex from skeletal remains is critical in the forensic context. The presence of the os coxae or skull can never be guaranteed, making the development of reliable methods of sex estimation using other skeletal elements necessary. Using a 724 individual calibration sample from the Hamann‐Todd collection, this study identifies sexual dimorphism in the human scapula, and presents a new five‐variable discriminant function for sex estimation. The overall accuracy of this method proved to be 95.7% on the cross‐validated calibration sample, 92.5% on an 80 individual test sample from the Hamann‐Todd collection, and 84.4% on a 32 individual test sample from the skeletal collection of the Wichita State University Biological Anthropology Laboratory. Additionally, a slightly less accurate two‐variable model was developed and has cross‐validated accuracy of 91.3%.     

The use of the Personality Assessment Inventory (PAI) in assessing offenders

The intersection between the legal and mental health professions is sometimes marked by controversy, and the application of psychological assessments to forensic issues is no exception. However, the field of psychological assessment holds particular promise for clarifying decision making within the forensic arena, as it can bring a particularly well-established body of theory and data to bear upon clinical forensic practice. This article describes one psychometric instrument, the Personality Assessment Inventory, as an example of how particular assessment instruments can help inform this process.     

Skeletal manifestations of bear scavenging

In many partially or fully skeletonized forensic cases, postmortem animal damage is simply attributed to rodents or carnivores; little effort is made to determine the general size or assign a genus to the scavenger. As one of the largest wild carnivores to inhabit mountainous and forested areas throughout the continental United States, Alaska, and Canada, black bears (Ursus americanus) must be considered possible suspects when skeletonized remains are located showing marks of carnivore damage. Since 1995, three cases of known bear scavenging have been referred to the Maxwell Museum's Laboratory of Human Osteology by the New Mexico Office of the Medical Investigator for skeletal analysis. These cases comprise a total of seven individuals, and all of the remains were deposited in high altitude forests of New Mexico along the western border with Arizona with a minimum of 4 months exposure before recovery. When analyzed, all cases shared a similar pattern of element survivorship and damage. We suggest that bears can be distinguished from members of the canid family, the other common scavenger of human remains, based on the representation of skeletal elements at the scene. Rates and patterns of damage are not as accurate as element recovery in the discrimination of scavenger genus. Use of this information should allow forensic anthropologists to better understand the postmortem taphonomic processes that shaped the skeletal remains, and hopefully prevent misdiagnoses of perimortem trauma on elements not typically scavenged by canids.     

“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。     

Preliminary evidence for an automatic link between sex and power among men who molest children

Understanding critical motivational processes of sexual offenders may ultimately provide important clues to more effective treatments. Implicit, automatic cognitive processes have received minimal attention; however, a lexical decision experiment revealed automatic links between the concepts of power and sex among participants who self-reported attraction to sexual aggression. The current study replicates this experiment with a group of male child molesters and forensic and analogue controls. Subliminally presented sex words elicited a facilitation effect for power words among child molesters only; that is, sex to power associations were evident, as well as a trend for the reverse. These results provide preliminary evidence for an automatic sex-power association in child molesters and may point to a crucial pathological link in the cognitive schemata of sex offenders. As well, the current study suggests that paradigms from cognitive psychology may contribute to multimodal (risk) assessment of sexual offenders.     

The effects of skeletal preparation techniques on DNA from human and non-human bone

The forensic pathologist increasingly relies on the forensic anthropologist to be the consulting expert in human identification. Likewise, if identification is not possible from visual inspection of skeletal remains, the forensic biologist may be called upon to conduct DNA analysis. The possibility of downstream DNA testing needs to be considered when skeletal preparation techniques are employed to deflesh human remains, as they have the potential to strongly impact genetic analyses and subsequent identification. In this study, three cleaning techniques, boiling bone in water, in bleach, and in powdered detergent/sodium carbonate, were tested for their effect on nuclear and mtDNA recovery from a variety of human and non-human bones. A statistically significant reduction in DNA yields occurred in non-human bones cleaned with bleach, and DNA degradation was apparent electrophoretically. The human bones also showed much lower yields from bleach cleaning, while the detergent/carbonate method allowed the largest segments of DNA to be amplified, indicating it may have a less degradative effect on bone DNA than either of the other cleaning processes.     

The reliability of forensic osteology--a case in point. Case study

The medico-legal investigation of skeletons is a trans-disciplinary effort by forensic scientists as well as physical anthropologists. The advent of DNA extraction and amplification from bones and teeth has led to the assumption that morphological assessment of skeletal remains might soon become obsolete. But despite the introduction and success of molecular biology, the analysis of skeletal biology will remain an integral part of the identification process. This is due to the fact, that the skeletal record allows relatively fast and accurate inferences about the identity of the victim. Moreover, a standard biological profile may be established to effectively narrow the police investigator's search parameters. The following study demonstrates how skeletal biology may collaborate in the forensic investigation and support DNA fingerprinting evidence.In this case, the information gained from standard morphological methods about the unknown person's sex, age and heritage immediately led the police to suspect, that the remains were that of a young man from Vietnam, who had been missing for 2.5 years. The investigation then quickly shifted to prove the victim's identity via DNA extraction and mtDNA sequence analysis and biostatistical calculations involving questions of kinship [4].     

Decision analysis in forensic science

Forensic scientists are routinely faced with the problems of making decisions under circumstances of uncertainty (i.e., to perform or not perform a test). A decision making model in forensic science is proposed, illustrated with an example from the field of forensic genetics. The approach incorporates available evidence and associated uncertainties with the assessment of utilities (or desirability of the consequences). The paper examines a general example for which identification will be made of the decision maker, the possible actions, the uncertain states of nature, the possible source of evidence and the kind of utility assessments required. It is argued that a formal approach can help to clarify the decision process and give a coherent means of combining elements to reach a decision.     

Sex assessment from the carpals bones: discriminant function analysis in a 20th century Spanish sample

Sex assessment is one of the first essential steps in human identification, in both medico-legal cases and bio-archaeological contexts. Fragmentary human remains compromised by different types of inhumation or physical insults may frustrate the use of the traditional sex estimation methods, such as the analysis of the skull and pelvis. Currently, the application of discriminant functions to sex unidentified skeletal remains is steadily increasing. However, several studies have demonstrated that, due to variation in size and patterns of sexual dimorphism, discriminant function equations are population-specific [1,2,5,12,61]. In this study, in order to improve sex assessment from skeletal remains and to establish population-specific discriminant functions, the diagnostic values of the carpal bones were considered. A sample of 100 individuals (50 males and 50 females) of known sex and age was analyzed. They belong to a 20th century identified collection from the Municipal Cemetery of "San José", Granada (Spain) and housed in the Laboratory of Anthropology, Faculty of Medicine, University of Granada (Spain). The age of the individuals ranged between 22 and 85 years. Between four and nine measurements of each carpal bone were performed [41,59]. Discriminant function statistics showed a sex assessment accuracy as high as 97.8%. The results suggest that carpal bones can be used for assessing sex in both forensic and bio-archaeological identification procedures.     

Limitations of Diagnostic Precision and Predictive Utility in the Individual Case: A Challenge for Forensic Practice

Knowledge of group tendencies may not assist accurate predictions in the individual case. This has importance for forensic decision making and for the assessment tools routinely applied in forensic evaluations. In this article, we applied Monte Carlo methods to examine diagnostic agreement with different levels of inter-rater agreement given the distributional characteristics of PCL-R scores. Diagnostic agreement and score agreement were substantially less than expected. In addition, we examined the confidence intervals associated with individual predictions of violent recidivism. On the basis of empirical findings, statistical theory, and logic, we conclude that predictions of future offending cannot be achieved in the individual case with any degree of confidence. We discuss the problems identified in relation to the PCL-R in terms of the broader relevance to all instruments used in forensic decision making.