Understanding 'error' in the forensic sciences: A primer.

This paper distils seven key lessons about 'error' from a collaborative webinar series between practitioners at Victoria Police Forensic Services Department and academics. It aims to provide the common understanding of error necessary to foster interdisciplinary dialogue, collaboration and research. The lessons underscore the inevitability, complexity and subjectivity of error, as well as opportunities for learning and growth. Ultimately, we argue that error can be a potent tool for continuous improvement and accountability, enhancing the reliability of forensic sciences and public trust. It is hoped the shared understanding provided by this paper will support future initiatives and funding for collaborative developments in this vital domain.

Diverse types of expertise in facial recognition.

Facial recognition errors can jeopardize national security, criminal justice, public safety and civil rights. Here, we compare the most accurate humans and facial recognition technology in a detailed lab-based evaluation and international proficiency test for forensic scientists involving 27 forensic departments from 14 countries. We find striking cognitive and perceptual diversity between naturally skilled super-recognizers, trained forensic examiners and deep neural networks, despite them achieving equivalent accuracy. Clear differences emerged in super-recognizers' and forensic examiners' perceptual processing, errors, and response patterns: super-recognizers were fast, biased to respond 'same person' and misidentified people with extreme confidence, whereas forensic examiners were slow, unbiased and strategically avoided misidentification errors. Further, these human experts and deep neural networks disagreed on the similarity of faces, pointing to differences in their representations of faces. Our findings therefore reveal multiple types of facial recognition expertise, with each type lending itself to particular facial recognition roles in operational settings. Finally, we show that harnessing the diversity between individual experts provides a robust method of maximizing facial recognition accuracy. This can be achieved either via collaboration between experts in forensic laboratories, or most promisingly, by statistical fusion of match scores provided by different types of expert.

Selecting police super-recognisers.

People vary in their ability to recognise faces. These individual differences are consistent over time, heritable and associated with brain anatomy. This implies that face identity processing can be improved in applied settings by selecting high performers-'super-recognisers' (SRs)-but these selection processes are rarely available for scientific scrutiny. Here we report an 'end-to-end' selection process used to establish an SR 'unit' in a large police force. Australian police officers (n = 1600) completed 3 standardised face identification tests and we recruited 38 SRs from this cohort to complete 10 follow-up tests. As a group, SRs were 20% better than controls in lab-based tests of face memory and matching, and equalled or surpassed accuracy of forensic specialists that currently perform face identification tasks for police. Individually, SR accuracy was variable but this problem was mitigated by adopting strict selection criteria. SRs' superior abilities transferred only partially to body identity decisions where the face was not visible, and they were no better than controls at deciding which visual scene that faces had initially been encountered in. Notwithstanding these important qualifications, we conclude that super-recognisers are an effective solution to improving face identity processing in applied settings.

Looking at faces in the wild.

Faces are key to everyday social interactions, but our understanding of social attention is based on experiments that present images of faces on computer screens. Advances in wearable eye-tracking devices now enable studies in unconstrained natural settings but this approach has been limited by manual coding of fixations. Here we introduce an automatic 'dynamic region of interest' approach that registers eye-fixations to bodies and faces seen while a participant moves through the environment. We show that just 14% of fixations are to faces of passersby, contrasting with prior screen-based studies that suggest faces automatically capture visual attention. We also demonstrate the potential for this new tool to help understand differences in individuals' social attention, and the content of their perceptual exposure to other people. Together, this can form the basis of a new paradigm for studying social attention 'in the wild' that opens new avenues for theoretical, applied and clinical research.

Let's talk about faces: Identifying faces from verbal descriptions.

Face descriptions inform real-world identification decisions, for example when eyewitnesses describe criminal perpetrators. However, it is unclear how effective face descriptions are for identification. Here, we examined the accuracy of face identification from verbal descriptions, and how individual differences in face perception relate to producing and using descriptions for identification. In Study 1, participants completed a face communication task in pairs. Each participant saw a single face, and via verbal communication only, the pair decided if they were viewing the same person or different people. Dyads achieved 72% accuracy, compared to 81% when participants completed the task individually by matching face pairs side-by-side. Performance on the face communication and perceptual matching tasks were uncorrelated, perhaps due to low measurement reliability of the face communication task. In subsequent studies, we examined the abilities of face 'describers' (Study 2) and 'identifiers' separately (Study 3). We found that 'super-recognizers' - people with extremely high perceptual face identification abilities - outperformed controls in both studies. Overall, these results show that people can successfully describe faces for identification. Preliminary evidence suggests that this ability - and the ability use facial descriptions for identification - has some association with perceptual face identification skill.

Eye contact and sociability data suggests that Australian dingoes were never domesticated.

Dogs were the first animal to become domesticated by humans, and they represent a classic model system for unraveling the processes of domestication. We compare Australian dingo eye contact and socialization with Basenji and German Shepherd dog (GSD) breeds. Australian dingoes arrived in Australia 5,000-8,000 BP, and there is debate whether they were domesticated before their arrival. The Basenji represents a primitive breed that diverged from the remaining breeds early in the domestication process, while GSDs are a breed dog selected from existing domestic dogs in the late 1800s. We conducted a 4-phase study with unfamiliar and familiar investigators either sitting passively or actively calling each canid. We found 75% of dingoes made eye contact in each phase. In contrast, 86% of Basenjis and 96% of GSDs made eye contact. Dingoes also exhibited shorter eye-gaze duration than breed dogs and did not respond to their name being called actively. Sociability, quantified as a canid coming within 1 m of the experimenter, was lowest for dingoes and highest for GSDs. For sociability duration, dingoes spent less time within 1 m of the experimenter than either breed dog. When compared with previous studies, these data show that the dingo is behaviorally intermediate between wild wolves and Basenji dogs and suggest that it was not domesticated before it arrived in Australia. However, it remains possible that the accumulation of mutations since colonization has obscured historical behaviors, and dingoes now exist in a feralized retamed cycle. Additional morphological and genetic data are required to resolve this conundrum.

The impact of recall timing on the preservation of eyewitness memory.

Two studies investigated the impact of recall timing on eyewitness memory. In Study 1, participants viewed a crime video and then completed the Self-Administered Interview (SAI©) either immediately, after a 24-h delay, after a 1-week delay, or not at all. All participants completed a final recall questionnaire 2 weeks after they had viewed the stimulus video. Study 2 aimed to determine how long the beneficial impact of the SAI© on witnesses' long-term memory lasts. Participants watched a crime video and then either completed the SAI© or did not engage in an immediate recall attempt. Participants then completed a final recall questionnaire after a delay of 24 h, 1 week, 2 weeks, or 1 month. The results indicated that initial recall should be completed within 24 h of an incident and that under these conditions, the beneficial impact of early recall on long-term memory endures for at least 1 month.

Diagnostic feature training improves face matching accuracy.

Identifying unfamiliar faces is surprisingly error-prone, even for experienced professionals who perform this task regularly. Previous attempts to train this ability have been largely unsuccessful, leading many to conclude that face identity processing is hard-wired and not amenable to further perceptual learning. Here, we take a novel expert knowledge elicitation approach to training, based on the feature-based comparison strategy used by high-performing professional facial examiners. We show that instructing novices to focus on the facial features that are most diagnostic of identity for these experts-the ears and facial marks (e.g., scars, freckles and blemishes)-improves accuracy on unfamiliar face matching tasks by 6%. This training takes just 6 min to complete and yet accounts for approximately half of experts' superiority on the task. Benefits of training are strongest when diagnostic features are clearly visible and absent when participants are trained to rely on nondiagnostic features. Our data-driven approach contrasts with theory-driven training that is designed to improve holistic face processing mechanisms associated with familiar face recognition. This suggests that protocols which bypass the core face recognition system-and instead reorient attention to features that are undervalued by novices-offer a more promising route to training for unfamiliar face matching. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Communicating forensic science opinion: An examination of expert reporting practices.

Forensic scientists endeavour to explain complex scientific principles to legal decision-makers with limited scientific training (e.g., police, lawyers, judges, and jurors). Much of the time this communication is limited to written opinions in expert reports. Notwithstanding considerable scientific research and debate about the best way to communicate forensic science opinions, it is unclear how much of the advice has translated into forensic science practice. In conducting this descriptive study, we examined the reporting practices adopted by forensic scientists across a range of forensic science disciplines. Specifically, we used a quantitative content analysis approach to identify the conclusion types and additional information submitted by forensic scientists in proficiency tests during 2016 ("What would be the wording of the Conclusions in your report?"). Our analysis of 500 randomly selected responses in eight disciplines indicated that the conclusion type which has received the most criticism in recent years (categorical statements) remains the preferred means of expression in a clear majority of responses. We also found that the provision of additional information often considered necessary for rational evaluation of the evidence (e.g., information about reliability and validity) was rarely reported. These results suggest limited engagement with recent recommendations and are concerning given the gravity of the legal decisions that hinge on accurate and transparent forensic science communication.

Forensic science evidence: Naive estimates of false positive error rates and reliability.

We do not know how often false positive reports are made in a range of forensic science disciplines. In the absence of this information it is important to understand the naive beliefs held by potential jurors about forensic science evidence reliability. It is these beliefs that will shape evaluations at trial. This descriptive study adds to our knowledge about naive beliefs by: (1) measuring jury-eligible (lay) perceptions of reliability for the largest range of forensic science disciplines to date, over three waves of data collection between 2011 and 2016 (n=674); (2) calibrating reliability ratings with false positive report estimates; and (3) comparing lay reliability estimates with those of an opportunity sample of forensic practitioners (n=53). Overall the data suggest that both jury-eligible participants and practitioners consider forensic evidence highly reliable. When compared to best or plausible estimates of reliability and error in the forensic sciences these views appear to overestimate reliability and underestimate the frequency of false positive errors. This result highlights the importance of collecting and disseminating empirically derived estimates of false positive error rates to ensure that practitioners and potential jurors have a realistic impression of the value of forensic science evidence.

Familiarity does not inhibit image-specific encoding of faces.

When matching and recognizing familiar faces, performance is unaffected by changes to image-specific details such as lighting, head angle, and expression. In contrast, these changes have a substantial impact on performance when faces are unfamiliar. What process can account for this difference? Recent evidence shows a memory disadvantage for remembering specific images of familiar people compared to unfamiliar people, suggesting that image invariance in familiar face processing may be supported by loss of image-specific details in memory. Here, we examine whether this cost results from loss of image specific details during encoding of familiar faces. Participants completed four tasks that required participants to retain image-specific information in working memory: duplicate detection (Experiment 1), change detection (Experiment 2), short-term recognition memory (Experiment 3 and 5), and visual search (Experiment 4). Across all experiments (combined n = 270), our results consistently show equivalent memory performance for specific images of familiar and unfamiliar faces. We conclude that familiarity does not influence encoding of pictorial details, suggesting that loss of image-specificity reported in previous work is a result of longer-term storage mechanisms. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Do professional facial image comparison training courses work?

Facial image comparison practitioners compare images of unfamiliar faces and decide whether or not they show the same person. Given the importance of these decisions for national security and criminal investigations, practitioners attend training courses to improve their face identification ability. However, these courses have not been empirically validated so it is unknown if they improve accuracy. Here, we review the content of eleven professional training courses offered to staff at national security, police, intelligence, passport issuance, immigration and border control agencies around the world. All reviewed courses include basic training in facial anatomy and prescribe facial feature (or 'morphological') comparison. Next, we evaluate the effectiveness of four representative courses by comparing face identification accuracy before and after training in novices (n = 152) and practitioners (n = 236). We find very strong evidence that short (1-hour and half-day) professional training courses do not improve identification accuracy, despite 93% of trainees believing their performance had improved. We find some evidence of improvement in a 3-day training course designed to introduce trainees to the unique feature-by-feature comparison strategy used by facial examiners in forensic settings. However, observed improvements are small, inconsistent across tests, and training did not produce the qualitative changes associated with examiners' expertise. Future research should test the benefits of longer examination-focussed training courses and incorporate longitudinal approaches to track improvements caused by mentoring and deliberate practice. In the absence of evidence that training is effective, we advise agencies to explore alternative evidence-based strategies for improving the accuracy of face identification decisions.

The effects of perceived memory ability on memory conformity for an event.

The present study investigated the impact of false feedback about individual memory performance relative to a co-witness on susceptibility to misinformation. Pairs of participants (n = 130; 65 pairs) completed a visual memory test and received false feedback on their performance indicating that the memory ability of one participant in the pair was stronger relative to the other participant. The participants then viewed a crime video (either the same video or one slightly different to their partner) and discussed their memories for this video with their co-witness. Participants completed a semi-cued recall task and a recognition test about the video. False memory feedback indicating lower relative performance was associated with significant increases in sensitivity to misinformation. The results are discussed in reference to the potential contributions that co-witnesses' perceptions of both their partner's reliability and their own reliability have on event memory.

Improving face identification with specialist teams.

People vary in their ability to identify faces, and this variability is relatively stable across repeated testing. This suggests that recruiting high performers can improve identity verification accuracy in applied settings. Here, we report the first systematic study to evaluate real-world benefits of selecting high performers based on performance in standardized face identification tests. We simulated a recruitment process for a specialist team tasked with detecting fraudulent passport applications. University students (n = 114) completed a battery of screening tests followed by a real-world face identification task that is performed routinely when issuing identity documents. Consistent with previous work, individual differences in the real-world task were relatively stable across repeated tests taken 1 week apart (r = 0.6), and accuracy scores on screening tests and the real-world task were moderately correlated. Nevertheless, performance gains achieved by selecting groups based on screening tests were surprisingly small, leading to a 7% improvement in accuracy. Statistically aggregating decisions across individuals-using a 'wisdom of crowds' approach-led to more substantial gains than selection alone. Finally, controlling for individual accuracy of team members, the performance of a team in one test predicted their performance in a subsequent test, suggesting that a 'good team' is not only defined by the individual accuracy of team members. Overall, these results underline the need to use a combination of approaches to improve face identification performance in professional settings.

More than a sum of parts: robust face recognition by integrating variation.

Familiarity incrementally improves our ability to identify faces. It has been hypothesized that this improvement reflects the refinement of memory representations which incorporate variation in appearance across encounters. Although it is established that exposure to variation improves face identification accuracy, it is not clear how variation is assimilated into internal face representations. To address this, we used a novel approach to isolate the effect of integrating separate exposures into a single-identity representation. Participants (n = 113) were exposed to either a single video clip or a pair of video clips of target identities. Pairs of video clips were presented as either a single identity (associated with a single name, e.g. Betty-Sue) or dual identities (associated with two names, e.g. Betty and Sue). Results show that participants exposed to pairs of video clips showed better matching performance compared with participants trained with a single clip. More importantly, identification accuracy was higher for faces presented as single identities compared to faces presented as dual identities. This provides the first direct evidence that the integration of information across separate exposures benefits face matching, thereby establishing a mechanism that may explain people's impressive ability to recognize familiar faces.

The Amplification of Common Somatic Symptoms by Posttraumatic Stress Disorder in Firefighters.

Posttraumatic stress disorder (PTSD) in emergency service personnel and other trauma-exposed populations is known to be associated with a variety of physical health problems. However, little attention has been paid to the health of ageing emergency service personnel, who may be forced into early medical retirement because of a combination of these issues. Currently employed (N = 274) Australian firefighters completed a cross-sectional survey using validated, self-report measures of PTSD and somatic symptoms. Analyses examined the association between probable PTSD and a range of common somatic symptoms, and whether any association differed depending on the age of the firefighters. Firefighters with PTSD reported greater levels of neurological (p = .024), gastrointestinal (p = .015), and cardiorespiratory (p = .027) symptoms compared to those without PTSD. After adjusting for sex, age, and rank, linear regression analysis demonstrated that PTSD was significantly associated with increased total somatic symptom severity (p = .024), with PTSD accounting for 9.8% of the variance in levels of somatic symptoms. There was no interaction between age and the association between PTSD and somatic symptom severity. These results suggest that PTSD is associated with a significant increase in a wide range of somatic symptoms among firefighters, regardless of age. The implications for the identification and treatment of PTSD are discussed.

Thinking forensics: Cognitive science for forensic practitioners.

Human factors and their implications for forensic science have attracted increasing levels of interest across criminal justice communities in recent years. Initial interest centred on cognitive biases, but has since expanded such that knowledge from psychology and cognitive science is slowly infiltrating forensic practices more broadly. This article highlights a series of important findings and insights of relevance to forensic practitioners. These include research on human perception, memory, context information, expertise, decision-making, communication, experience, verification, confidence, and feedback. The aim of this article is to sensitise forensic practitioners (and lawyers and judges) to a range of potentially significant issues, and encourage them to engage with research in these domains so that they may adapt procedures to improve performance, mitigate risks and reduce errors. Doing so will reduce the divide between forensic practitioners and research scientists as well as improve the value and utility of forensic science evidence.

Evaluating the feature comparison strategy for forensic face identification.

Face recognition is thought to rely on representations that encode holistic properties. Paradoxically, professional forensic examiners who identify unfamiliar faces by comparing facial images are trained to adopt a feature-by-feature comparison strategy. Here we tested the effectiveness of this strategy by asking participants to rate facial feature similarity prior to making same/different identity decisions to pairs of face images. Experiment 1 provided preliminary evidence that rating feature similarity improves unfamiliar face matching accuracy in novice participants. In Experiment 2, we found benefits of this procedure over and above rating similarity of personality traits and image quality parameters, suggesting that benefits are not solely attributable to general increases in attention. In Experiment 3, we then compared performance of trained forensic facial image examiners to novice participants, and found that examiners displayed: i) superior face matching accuracy; ii) smaller face inversion and feature inversion effects; and iii) feature ratings that were more diagnostic of identity. Further, aggregating feature ratings of multiple examiners produced perfect identity discrimination. Based on these quantitative and qualitative differences between experts and novices, we conclude that comparison based on local features confers specific benefits to trained forensic examiners. (PsycINFO Database Record

Do emotional stimuli enhance or impede recall relative to neutral stimuli? An investigation of two "false memory" tasks.

Many eyewitness memory situations involve negative and distressing events; however, many studies investigating "false memory" phenomena use neutral stimuli only. The aim of the present study was to determine how both the Deese-Roediger-McDermott (DRM) procedure and the Misinformation Effect Paradigm tasks were related to each other using distressing and neutral stimuli. Participants completed the DRM (with negative and neutral word lists) and viewed a distressing or neutral film. Misinformation for the film was introduced and memory was assessed. Film accuracy and misinformation susceptibility were found to be greater for those who viewed the distressing film relative to the neutral film. Accuracy responses on both tasks were related, however, susceptibility to the DRM illusion and Misinformation Effect were not. The misinformation findings support the Paradoxical Negative Emotion (PNE) hypothesis that negative stimuli will lead to remembering more accurate details but also greater likelihood of memory distortion. However, the PNE hypothesis was not supported for the DRM results. The findings also suggest that the DRM and Misinformation tasks are not equivalent and may have differences in underlying mechanisms. Future research should focus on more ecologically valid methods of assessing false memory.