The role of estimator variables in eyewitness identification

This article was published Online First February 1, 2018Estimator variables are factors that can affect the accuracy of eyewitness identifications but that are outside of the control of the criminal justice system. Examples include (1) the duration of exposure to the perpetrator, (2) the passage of time between the crime and the identification (retention interval), (3) the distance between the witness and the perpetrator at the time of the crime. Suboptimal estimator variables (e.g., long distance) have long been thought to reduce the reliability of eyewitness identifications (IDs), but recent evidence suggests that this is not true of IDs made with high confidence and may or may not be true of IDs made with lower confidence. The evidence suggests that while suboptimal estimator variables decrease discriminability (i.e., the ability to distinguish innocent from guilty suspects), they do not decrease the reliability of IDs made with high confidence. Such findings are inconsistent with the longstanding “optimality hypothesis” and therefore require a new theoretical framework. Here, we propose that a signal-detection-based likelihood ratio account – which has long been a mainstay of basic theories of recognition memory – naturally accounts for these findings.Carolyn Semmler, John Dunn, Laura Mickes, John T. Wixte

Do sequential lineups impair underlying discriminability?

© 2020, The Author(s). Debate regarding the best way to test and measure eyewitness memory has dominated the eyewitness literature for more than 30 years. We argue that resolution of this debate requires the development and application of appropriate measurement models. In this study we developed models of simultaneous and sequential lineup presentations and used these to compare these procedures in terms of underlying discriminability and response bias, thereby testing a key prediction of diagnostic feature detection theory, that underlying discriminability should be greater for simultaneous than for stopping-rule sequential lineups. We fit the models to the corpus of studies originally described by Palmer and Brewer (2012, Law and Human Behavior, 36(3), 247–255), to data from a new experiment and to eight recent studies comparing simultaneous and sequential lineups. We found that although responses tended to be more conservative for sequential lineups there was little or no difference in underlying discriminability between the two procedures. We discuss the implications of these results for the diagnostic feature detection theory and other kinds of sequential lineups used in current jurisdictions

Profiling the Facial Comparison Practitioner in Australia

This report details the performance of professional and expert facial comparison practitioners working in the Australian policing and national security context. As part of a joint University of Adelaide - Defence Science and Technology Group project, known as the Human Operator Capability Project, a comprehensive survey of 149 facial comparison practitioners within Australian State and Federal Government agencies was conducted in late 2010. The survey collected data in a range of categories including: demographics, training and work history, facial comparison tools and techniques, attitudes to the facial comparison task and use of facial recognition systems. This report outlines the key findings from the survey, including implications for the consideration of participating agencies at the time. An epilogue reflects on what has changed in the time since the survey was conducted

Letting go of the Grail: Falsifying the theory of ‘true’ eyewitness identifications

Various formal and informal models of eyewitness memory have been proposed. While serving to guide both the construct and analytical frameworks of research within the field, these models have yet to be critically tested through a process of empirical falsification. This study addresses this gap by critically testing four hypotheses: the hypotheses that eyewitness memory possesses both (1) random-scale and (2) monotonic-likelihood representation; the hypothesis that eyewitness memory data is (3) accurately predicted by high-threshold (HT) models; and the hypothesis that a mathematical model of eyewitness identification provides a (4) good representation of the psychological constructs of eyewitness memory and decision making. After investigating the Block-Marschak inequalities test for random-scale and monotonic-likelihood representation and developing a new critical test for the falsification of the high threshold (HT) models, two experiments were conducted online with a total of 5,056 participants recruited from Amazon Mechanical Turk. Experiment 1 collected k-AFC probabilities for lineup sizes k ∈ {2,…,7}. Experiment 2 collected identification and ranking probabilities from a simultaneous 8-item lineup using a 3 (strong, weak, very weak memory) x 2 (low vs high expectation) x 2 (target-present vs target-absent) between-subject experimental design. Eyewitness identification outcomes were shown to have both random-scale and monotonic likelihood representation, thus allowing for development of a mathematical model. The 2HT models of eyewitness memory were falsified and superseded by an alternative surviving model—signal detection theory (SDT). Finally, the predictive ability of the unequal-variance (UV) SDT model of simultaneous lineup identification (assuming a MAX decision rule) was confirmed, as was the independence of the model’s parameters and its generalizability across task structures. It was concluded that the UV-SDT class of models provide an evidence-based account of eyewitness identification behavior, support the measurement of empirical eyewitness identification data, and have facilitated a shift towards the building of stronger scientific evidence

Juror comprehension of DNA evidence: the effect of timing and judicial instruction on coherence-shifts

This project aims to investigate whether an attempt to mitigate bias perceptions of DNA evidence by manipulating the timing of the forensic evidence and judicial instruction will be effective. Mock-jurors have demonstrated that they often do not attribute appropriate strength to forensic evidence during a trial. It is known that jurors reason by creating a story (Pennington & Hastie, 1986; 1992; 1993), however, little is known about the inferential process by which jurors actually integrate the competing and contradictory pieces of evidence. Coherence-shifts have been referred to under many different names, including; inference to the best explanation, pre-decisional information distortion and related concepts such as the assimilation hypothesis and explanatory coherence which also fit within a paradigm of this study’s interest. These models indicate (herein after referred to as ‘coherence-shifts’), that early during the decision making process, a preferred decision emerges. The individual pieces of evidence in support of this preferred decision thereafter are attributed more weight, causing a 'coherence-shift.' This has the potential implication that the prosecution have an inherent advantage over the defence in presenting their evidence first. Although this is an institutional process which cannot be changed and is needed (the prosecution need to establish their case first), it may be the case that even within the prosecution case presenting DNA evidence early contributes to the distortion and inappropriate evaluation of that evidence. Judicial instructions have been studied with mixed results. Typically, the judicial instructions are given later in the trial, despite studies showing that they are ineffective, with some studies finding that judicial instructions given at the end of the trial have no effect at all (Dartnall & Goodman-Delahunty, 2006). However, this may be due to a lack of engagement or ability to apply the instruction to the decision process on behalf of the mock-jurors. Kassin & Wrightsman (1979) found judicial instruction given at the beginning of the trial to be more effective, resulting in fewer guilty verdicts. However, there is a gap in the literature on examining instruction around fallacious reasoning around DNA evidence. This research aims to contribute to the knowledge on juror comprehension of forensic evidence by filling a gap in the literature on timing of forensic evidence. It aims to assess if a judicial instruction given early in the trial can aid jurors to better evaluate DNA evidence. This could justify more research on a connectionist model of inferential reasoning, if results indicate that presenting the same forensic evidence at different time points impacts on decisions

Similarity and set size impact the efficiency of hypothesis testing among faces

Face processing is an important cognitive process that has been extensively studied in the domains of recognition memory and visual search. However, with the advent of biometric question- answering systems to assist experts searching for specific individuals, it is increasingly important to understand if the known biases and strengths of face processing extend to more deliberate natural language question formation and search. In this work we present a novel experimental task where people ask natural language questions to test hypotheses about faces in which the efficiency of the questions can be directly observed. The results indicate some aspects of existing paradigms do transfer to hypothesis testing, including less efficient questions when the number of items increases or as the similarity be- tween items increases. However, unlike recognition memory specific demographic features (gender and ethnicity) do not seem to have a strong impact on efficiency

Meat Related Cognitive Dissonance

Exploring the mechanisms and theories that explain meat consumption and the relationships between animals and humans

The effectiveness of meditation in preventing burnout in high-risk occupations: a systematic review protocol

This is a protocol outlining a review with the aim to evaluate the effectiveness of meditation in preventing burnout in emergency services workers, military personnel, corporate executives, and healthcare workers. A meta-analysis will be conducted using psychological and physiological measures of stress and burnout. Burnout is framed as a state of physical and mental exhaustion encoded in a diagnosis by Z73.0 in the ICD-10-CM and negatively affects an individual’s psychological and physical health. It also decreases work performance and affects employers through increased absenteeism and employee turnover. Mindfulness intervention is the most reported intervention for burnout and has been found to offer statistically significant effects in improving stress levels and reducing burnout. Recent research has examined focused meditation, a particular type of mindfulness training, and the role of its effects of attentional regulation and emotion regulation in reducing stress and burnout. Studies will be included which have participants working in high-risk areas including emergency services, the military, corporate executive management or healthcare workers who participated in a meditation intervention prior to the onset of burnout. Psychological outcomes, including Maslach Burnout Inventory (MBI), Shirom-Melamed Burnout Measure (SMBM), Health and Safety Executive (HSE), Bergen Burnout Inventory (BBI) and Perceived Stress Scale (PSS), and physiological outcomes including cortisol levels, heart rate variability, blood pressure, stress reactivity, hypothalamic-pituitary adrenal axis (HPA) and levels of neurotransmitters (dopamine, serotonin, oxytocin and vasopressin) will be used to assess the effectiveness of the meditation intervention. The PsycINFO, PubMed and CINAHL database search and a meta-analysis will be conducted comparing data extracted from standard burnout measures and inventories and physiological measures

R Code for Eyewitness Data

This is a repository for code presented at the SARMAC regional meeting 201