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.

Seven different potential sources of bias are presented in Fig. 1 (for their full descriptions and examples see (1)). They include innate sources relating to the mere fact that we are human (the very bottom of the taxonomy), general sources that emerge from the experience, training and environment in which forensic examiners operate, and also the specifics of the case being investigated (the top of the taxonomy that includes the improper use of reference material as "targets" that drive the forensic comparison-suspect-driven bias-i.e., working back-ward from the suspect/target to the evidence, rather than the other way around; see (1,2) for details). Official bodies, such as the UK Forensic Regulator (3) and the US National Commission on Forensic Science (4), have now acknowledged the potential of cognitive bias in forensic work.However, the question remains as to the mechanisms of how such sources translate to actually cause bias. Here, we should distinguish between the bias cascade and the bias snowball effects.Consider, for example, that in some jurisdictions, the CSI personnel who collect evidence from the crime scene are the same people who also do the forensic work back in the labora-tory. In such cases, the analysis, evaluations, interpretations, and conclusions at the forensic laboratory may be influenced by irrelevant contextual information that examiners may have been exposed to at the crime scene. It is not always simple and self-evident what information is relevant and what is irrelevant, but clearly there are many pieces of information that are totally irrelevant to the forensic examiner (see the National Commis-sion on Forensic Science document "Ensuring that forensic analysis is based upon task-relevant information" (4)). The bias cascade effect is when bias arises as a result of irrelevant infor-mation cascading from one stage to another, e.g., from the ini-tial evidence collection to the evaluation and interpretation of the evidence.The bias cascade effect can take many forms, all sharing the characteristic that irrelevant information in Time 1 (e.g., during evidence collection at the crime scene) cascades to Time 2 (e.g., when the evidence is interpreted). Countering such bias cascade can be achieved by controlling the information flow between the different stages of the forensic investigation (2,5,6).First, it is best to have different people involved at the various stages of the forensic investigation. For example, it is ill-advised that those who collect evidence at the crime scene (who are exposed to a variety of contextual information, much of it needed to do their job) will be the same people who examine and interpret the evidence back at the forensic laboratory

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.

There has been an increased engagement by researchers in understanding the decision-making processes that occur within forensic science. There is a rapidly growing evidence base underpinning our understanding of decision-making and human factors and this body of work is the foundation for achieving truly improved decision-making in forensic science. Such an endeavour is necessary to minimise the misinterpretation of scientific evidence and maximise the effectiveness of crime reconstruction approaches and their application within the criminal justice system. This paper proposes and outlines a novel six phased approach for how a broadening and deepening knowledge of decision-making in forensic science can be articulated and incorporated into the spheres of research, practice, education, and policy making within forensic science specifically, and the criminal justice system more generally. Phases 1 and 2 set out the importance of systematic examination of the decisions which play a role throughout forensic reconstruction and legal processes. Phase 3 focuses on how these decisions can, and should, be studied to understand the underlying mechanisms and contribute to reducing the occurrence of misleading decisions. Phase 4 highlights the ways in which the results and implications of this research should be communicated to the forensic community and wider criminal justice system. Lastly, the way in which the forensic science domain can move forwards in managing the challenges of human decision-making and create and embed a culture of acceptance and transparency in research, practice and education (learning and training) are presented in phases 5 and 6. A consideration of all 6 connected phases offers a pathway for a holistic approach to improving the transparency and reproducibility of decision making within forensic science. 1 CJS decision map 2 Empirical study of decision mechanisms 3 Communicating the outcomes of decision making research 4 Managing risk 5 Education and training 6