Human factors in forensic science: The cognitive mechanisms that underlie forensic feature-comparison expertise

After a decade of critique from leading scientific bodies, forensic science research is at a crossroads. Whilst emerging research has shown that some forensic feature-comparison disciplines are not foundationally valid, others are moving towards establishing reliability and validity. Forensic examiners in fingerprint, face and handwriting comparison disciplines have skills and knowledge that distinguish them from novices. Yet our understanding of the basis of this expertise is only beginning to emerge. In this paper, we review evidence on the psychological mechanisms contributing to forensic feature-comparison expertise, with a focus on one mechanism: statistical learning, or the ability to learn how often things occur in the environment. Research is beginning to emphasise the importance of statistical learning in forensic feature-comparison expertise. Ultimately, this research and broader cognitive science research has an important role to play in informing the development of training programs and selection tools for forensic feature-comparison examiners

The effects of dams on longitudinal variation in river food webs

We examined the effects of two dams on longitudinal variation of riverine food webs using stable isotope and gut contents analyses along four rivers in the Hunter Valley in eastern Australia. Longitudinal 15N enrichment was observed in most invertebrate taxa and food sources but significant longitudinal variation was rare for 13C, and composition of gut contents of invertebrate taxa did not vary significantly with longitudinal position. Most invertebrates and food sources were more 15N-enriched at sites immediately downstream of the dams than expected from their upstream longitudinal position, a result not mirrored by gut contents and 13C. Enrichment of 15N downstream may be attributed to altered water quality as a result of impoundment but further research is necessary to elucidate whether physico-chemical riverine processes or trophic mechanisms are responsible. Our observations regarding the influence of dams on isotope ratios are contrary to the few existing studies, suggesting the small volumes relative to annual inflows of dams in the present study limit downstream impacts by maintaining aspects of flow variability. © 2013 © 2013 Taylor & Francis

Astacopsis gouldi Clark in streams of the Gog Range, northern Tasmania: the effects of catchment disturbance

Populations of the giant freshwater crayfish, Astrzcopsisgoufdi, were sampled in the Gog Range, northern Tasmania. Ten sites were sampled in relatively undisturbed and minimally disturbed areas, and in areas with a history of severe catchment disturbance. Larger numbers of A. gouldi were caught in two streams with undisturbed catchments than in three streams in heavily disturbed catchments. Thus, the abundance of A. gouldi in the Cog Range appears to have been adversely affected as a result of the disturbance of the original vegetation. Although the precise mechanism of the impact cannot be determined from this study, sedimentation and the presence of culverts may be preventing recolonisation of the disturbed streams. This study indicates the potential for catchment disturbance to affect populations of A. gouldi and highlights the need for proper management of land uses that may be detrimental to this species

Predicting and projecting memory: Error and bias in metacognitive judgments underlying testimony evaluation

This is the final version. Available on open access from Wiley via the DOI in this recordPreregistration, data, and materials underlying the proposed work are available on OSF at: https://osf.io/ms3f4/?view_only=f6ddb94b127045b1b3b7a487bbe8d874Purpose: Metacognitive judgments of what another person would remember had they experienced a stimulus – i.e., social metamemory judgments, are likely to be important in evaluations of testimony in criminal and civil justice systems. This paper develops and tests predictions about two sources of error in social metamemory judgments that have the potential to be important in legal contexts – errors resulting from beliefs informed by own memory being inappropriately applied to the memory of others, and errors resulting from differential experience of an underlying stimulus. Method: We examined social metamemory judgments in two experimental studies. In Experiment 1 (N = 323) participants were required to make either social metamemory judgments relating to faces or predictions relating to their own memory for faces. In Experiment 2 (N = 275), we manipulated participant experience of faces, holding the described experience of the person whose memory was being assessed constant and asked participants to make social metamemory judgments. Results: As predicted, judgments relating to the memory of others were prone to inaccuracy. While participants making predictions relating to their own memory performed above chance, participants making social metamemory judgments performed no better than chance. Social metamemory judgments were also influenced by the way stimuli were experienced by an assessor, even where this experience did not correspond to the experience of the person whose memory they were assessing. Conclusions: Having our own experiences of memory does not necessarily make us well-placed to assess the memory of others and, in fact, our own experiences of memory can even be misleading in making judgments about the memory of others.UK Research and Innovatio

Influence of hydroperiod on aquatic food-web structure and energy production in a floodplain wetland:implications for environmental flow management

Context: Environmental water is often used to manage floodplain wetlands that support many taxa, both terrestrial and aquatic. It is important to optimise the managed hydroperiod to maximise the provision of aquatically derived resources from wetlands. Aims: To test the hypothesis that increasing hydroperiod affects food-web structure and energy production in floodplain wetlands. Methods: Fatty acids and stable isotopes of δ13C and δ15N were used to define food-web structure, and estimate total energy production throughout a managed inundation event in a wetland in the northern Murray-Darling Basin. Key results: Food-web complexity increased with an increasing hydroperiod in line with predictable patterns of community assemblage development, before reducing sharply immediately prior to drying. Energy availability increased with an increasing hydroperiod and there was a strong correlation (ρ = 0.669, P = 0.0001) between energy availability and fatty acid concentration, which was in turn related to patterns of taxon occurrence. Conclusions and implications: Hydroperiod exerts a strong influence on aquatic invertebrate community trophic dynamics and energy provision. Planned flows should support maturation and stabilisation of the invertebrate community to optimise energy provision to consumers.</p

The low prevalence effect in fingerprint comparison amongst forensic science trainees and novices

The low prevalence effect is a phenomenon whereby target prevalence affects performance in visual search (e.g., baggage screening) and comparison (e.g., fingerprint examination) tasks, such that people more often fail to detect infrequent target stimuli. For example, when exposed to higher base-rates of ‘matching’ (i.e., from the same person) than ‘non-matching’ (i.e., from different people) fingerprint pairs, people more often misjudge ‘non-matching’ pairs as ‘matches’–an error that can falsely implicate an innocent person for a crime they did not commit. In this paper, we investigated whether forensic science training may mitigate the low prevalence effect in fingerprint comparison. Forensic science trainees (n = 111) and untrained novices (n = 114) judged 100 fingerprint pairs as ‘matches’ or ‘non-matches’ where the matching pair occurrence was either high (90%) or equal (50%). Some participants were also asked to use a novel feature-comparison strategy as a potential attenuation technique for the low prevalence effect. Regardless of strategy, both trainees and novices were susceptible to the effect, such that they more often misjudged non-matching pairs as matches when non-matches were rare. These results support the robust nature of the low prevalence effect in visual comparison and have important applied implications for forensic decision-making in the criminal justice system

Statistical feature training improves fingerprint-matching accuracy in novices and professional fingerprint examiners

AbstractForensic science practitioners compare visual evidence samples (e.g. fingerprints) and decide if they originate from the same person or different people (i.e. fingerprint ‘matching’). These tasks are perceptually and cognitively complex—even practising professionals can make errors—and what limited research exists suggests that existing professional training is ineffective. This paper presents three experiments that demonstrate the benefit of perceptual training derived from mathematical theories that suggest statistically rare features have diagnostic utility in visual comparison tasks. Across three studies (N = 551), we demonstrate that a brief module training participants to focus on statistically rare fingerprint features improves fingerprint-matching performance in both novices and experienced fingerprint examiners. These results have applied importance for improving the professional performance of practising fingerprint examiners, and even other domains where this technique may also be helpful (e.g. radiology or banknote security).</jats:p

Quantifying the Impact of Water Abstraction for Low Head ‘Run of the River’ Hydropower on Localized River Channel Hydraulics and Benthic Macroinvertebrates

‘Run of the river’ (ROR) hydropower schemes have undergone a recent resurgence in Europe, and with legislation requiring the protection and enhancement of the physical and ecological condition of European rivers, there is a need to understand the impacts of these schemes. This paper presents an assessment of the eco-hydraulic impact of a ROR hydropower scheme in the Peak District National Park, UK. Due to the ponded nature of the depleted stretch at the study site, this paper focuses on the characterization of the hydraulic impact of water abstraction for a ROR scheme at the hydropower outlet and samples microhabitats of benthic macroinvertebrates within the hydraulically affected zones. Measurement of hydraulic transects shows that the scheme's operation notably alters river channel hydraulics at 60% of water depth, whilst impacts are much less distinct in close proximity to the river bed. We identify eco-hydraulic relationships between benthic macroinvertebrate communities and localized near-bed velocity and turbulence conditions, thus indicating the potential for water abstraction by ROR schemes to impact lower trophic levels of riverine ecosystems. However, spatial patch-scale (10–100 m2) meso-habitat comparisons of invertebrate communities around the hydropower outlet showed only subtle differences, suggesting that in this case benthic communities are only minimally impacted by the ROR scheme