An introduction to forensic linguistics:language in evidence

From the accusation of plagiarism in The Da Vinci Code, to the infamous hoaxer in the Yorkshire Ripper case, the use of linguistic evidence in court and the number of linguists called to act as expert witnesses in court trials has increased rapidly in the past fifteen years. An Introduction to Forensic Linguistics: Language in Evidence provides a timely and accessible introduction to this rapidly expanding subject. Using knowledge and experience gained in legal settings – Malcolm Coulthard in his work as an expert witness and Alison Johnson in her work as a West Midlands police officer – the two authors combine an array of perspectives into a distinctly unified textbook, focusing throughout on evidence from real and often high profile cases including serial killer Harold Shipman, the Bridgewater Four and the Birmingham Six. Divided into two sections, 'The Language of the Legal Process' and 'Language as Evidence', the book covers the key topics of the field. The first section looks at legal language, the structures of legal genres and the collection and testing of evidence from the initial police interview through to examination and cross-examination in the courtroom. The second section focuses on the role of the forensic linguist, the forensic phonetician and the document examiner, as well as examining in detail the linguistic investigation of authorship and plagiarism. With research tasks, suggested reading and website references provided at the end of each chapter, An Introduction to Forensic Linguistics: Language in Evidence is the essential textbook for courses in forensic linguistics and language of the law.

Forensic linguistics : the application of language description in legal contexts

In this article I first divide Forensic Linguistics into three sub-disciplines: the language of written legal texts, the spoken language of legal proceedings, and the linguist as expert witness and then go on to give a small number of examples of the research undertaken in these three areas. For the language of written legal texts, I present work on the (in) comprehensibility of police cautions and of judges instructions to juries. For the spoken language of legal proceedings, I report work on the problems of interpreted interaction, of vulnerable witnesses and the need for more detailed research comparing the interactive rules in adversarial and investigative systems. Finally, to illustrate the role of the linguist as expert witness I report a trademark case, five different authorship attribution cases, three very different plagiarism cases and I end reporting briefly the contribution of linguists to language assessment techniques used in the linguistic classification of asylum seekers. © Langage et société no 132 - juin 2010.

The National Institute of Justice guide for eyewitness identification evidence: Can it improve juror decision-making?

Mistaken eyewitness identifications of innocent lead to more false convictions in the United States than any other cause. In response to concerns about the reliability of eyewitness evidence, the National Institute of Justice (NIJ) in 1999 published a Guide for the gathering and preservation of eyewitness evidence by law enforcement personnel. Previous research has shown that eyewitness identifications are more accurate when obtained using procedures recommended in the NIJ Guide. This experiment assessed whether informing jurors about the Guide can improve their ability to discriminate between eyewitness identifications likely to be accurate and those likely to be inaccurate and, if so, how to most effectively provide jurors with such information. ^ Seven hundred sixteen U.S. citizens who reported for criminal jury duty participated. Half of the participant jurors read a summary of an armed robbery trial in which the police followed the NIJ Guide when obtaining an eyewitness identification of the defendant. The other half read about an identical case in which the police did not follow the Guide. Jurors received information about the Guide from a court-appointed expert witness, one of the attorneys in the case, the trial judge, the judge in combination with one of the attorneys, or from no one (in the control groups). Jurors then rendered a verdict in the case and answered questions about the evidence in the case. ^ When an expert witness or the judge (either alone or in combination with one of the attorneys) informed jurors about the Guide, the jurors voted to convict defendants likely to be guilty and to acquit defendants likely to be innocent more often than did uninformed jurors assigned to a control group. These data suggest that informing jurors about the NIJ Guide using expert testimony or instructions from a judge will improve the quality and accuracy of jurors' verdict decisions in cases involving eyewitness identification evidence. However, more research is needed to determine whether the judge will remain an effective source of information about the Guide in a longer, more detailed trial scenario and to learn more about the underlying psychological processes governing the effects observed in this experiment. ^

Evaluation of contact and non-contact trapping efficiencies of human scent chemical profiles and their stabilities under different environmental conditions

Establishing an association between the scent a perpetrator left at a crime scene to the odor of the suspect of that crime is the basis for the use of human scent identification evidence in a court of law. Law enforcement agencies gather evidence through the collection of scent from the objects that a perpetrator may have handled during the execution of the criminal act. The collected scent evidence is consequently presented to the canines for identification line-up procedures with the apprehended suspects. Presently, canine scent identification is admitted as expert witness testimony, however, the accurate behavior of the dogs and the scent collection methods used are often challenged by the court system. The primary focus of this research project entailed an evaluation of contact and non-contact scent collection techniques with an emphasis on the optimization of collection materials of different fiber chemistries to evaluate the chemical odor profiles obtained using varying environment conditions to provide a better scientific understanding of human scent as a discriminative tool in the identification of suspects. The collection of hand odor from female and male subjects through both contact and non-contact sampling approaches yielded new insights into the types of VOCs collected when different materials are utilized, which had never been instrumentally performed. Furthermore, the collected scent mass was shown to be obtained in the highest amounts for both gender hand odor samples on cotton sorbent materials. Compared to non-contact sampling, the contact sampling methods yielded a higher number of volatiles, an enhancement of up to 3 times, as well as a higher scent mass than non-contact methods by more than an order of magnitude. The evaluation of the STU-100 as a non-contact methodology highlighted strong instrumental drawbacks that need to be targeted for enhanced scientific validation of current field practices. These results demonstrated that an individual's human scent components vary considerably depending on the method used to collect scent from the same body region. This study demonstrated the importance of collection medium selection as well as the collection method employed in providing a reproducible human scent sample that can be used to differentiate individuals.

Judging psychology experts: Can judges and attorneys distinguish between clinical and experimental psychologists?

A trial judge serves as gatekeeper in the courtroom to ensure that only reliable expert witness testimony is presented to the jury. Nevertheless, research shows that while judges take seriously their gatekeeper status, legal professionals in general are unable to identify well conducted research and are unable to define falsifiability, error rates, peer review status, and scientific validity (Gatkowski et al., 2001; Kovera & McAuliff, 2000). However, the abilities to identify quality scientific research and define scientific concepts are critical to preventing "junk" science from entering courtrooms. Research thus far has neglected to address that before selecting expert witnesses, judges and attorneys must first evaluate experts' CVs rather than their scientific testimony to determine whether legal standards of admissibility have been met. The quality of expert testimony, therefore, largely depends on the ability to evaluate properly experts' credentials. Theoretical models of decision making suggest that ability/knowledge and motivation are required to process information systematically. Legal professionals (judges and attorneys) were expected to process CVs heuristically when rendering expert witness decisions due to a lack of training in areas of psychology expertise.^ Legal professionals' (N = 150) and undergraduate students' (N = 468) expert witness decisions were examined and compared. Participants were presented with one of two versions of a criminal case calling for the testimony of either a clinical psychology expert or an experimental legal psychology expert. Participants then read one of eight curricula vitae that varied area of expertise (clinical vs. legal psychology), previous expert witness experience (previous experience vs. no previous experience), and scholarly publication record (30 publications vs. no publications) before deciding whether the expert was qualified to testify in the case. Follow-up measures assessed participants' decision making processes.^ Legal professionals were not better than college students at rendering quality psychology expert witness admissibility decisions yet they were significantly more confident in their decisions. Legal professionals rated themselves significantly higher than students in ability, knowledge, and motivation to choose an appropriate psychology expert although their expert witness decisions were equally inadequate. Findings suggest that participants relied on heuristics, such as previous expert witness experience, to render decisions.^

'The witness who saw, /He left little doubt' : a comparative consideration of expert testimony in mental disability law cases in common and civil law systems

The question of how courts assess expert evidence - especially when mental disability is an issue - raises the corollary question of whether courts adequately evaluate the content of the expert testimony or whether judicial decision making may be influenced by teleology (cherry picking evidence), pretextuality (accepting experts who distort evidence to achieve socially desirable aims), and/or sanism (allowing prejudicial and stereotyped evidence). Such threats occur despite professional standards in forensic psychology and other mental health disciplines that require ethical expert testimony. The result is expert testimony that, in many instances, is at best incompetent and at worst biased. The paper details threats to competent expert testimony in a comparative law context - in both the common law (involuntary civil commitment laws and risk assessment criminal laws) and, more briefly, civil law. We conclude that teleology, pretextuality, and sanism have an impact upon judicial decision making in both the common law and civil law. Finally, we speculate as to whether the new United Nations Convention on the Rights of Persons with Disabilities is likely to have any impact on practices in this area. Copyright © 2009 John Wiley & Sons, Ltd.

Linking the witness simulation software to an expert system to represent a decision-making process

Expert systems, and artificial intelligence more generally, can provide a useful means for representing decision-making processes. By linking expert systems software to simulation software an effective means of including these decision-making processes in a simulation model can be achieved. This paper demonstrates how a commercial-off-the-shelf simulation package (Witness) can be linked to an expert systems package (XpertRule) through a Visual Basic interface. The methodology adopted could be used for models, and possibly software, other than those presented here.

How useful is expert opinion for predicting the distribution of a species within and beyond the region of expertise? A case study using brush-tailed rock-wallabiesPetrogale penicillata

1. Species' distribution modelling relies on adequate data sets to build reliable statistical models with high predictive ability. However, the money spent collecting empirical data might be better spent on management. A less expensive source of species' distribution information is expert opinion. This study evaluates expert knowledge and its source. In particular, we determine whether models built on expert knowledge apply over multiple regions or only within the region where the knowledge was derived. 2. The case study focuses on the distribution of the brush-tailed rock-wallaby Petrogale penicillata in eastern Australia. We brought together from two biogeographically different regions substantial and well-designed field data and knowledge from nine experts. We used a novel elicitation tool within a geographical information system to systematically collect expert opinions. The tool utilized an indirect approach to elicitation, asking experts simpler questions about observable rather than abstract quantities, with measures in place to identify uncertainty and offer feedback. Bayesian analysis was used to combine field data and expert knowledge in each region to determine: (i) how expert opinion affected models based on field data and (ii) how similar expert-informed models were within regions and across regions. 3. The elicitation tool effectively captured the experts' opinions and their uncertainties. Experts were comfortable with the map-based elicitation approach used, especially with graphical feedback. Experts tended to predict lower values of species occurrence compared with field data. 4. Across experts, consensus on effect sizes occurred for several habitat variables. Expert opinion generally influenced predictions from field data. However, south-east Queensland and north-east New South Wales experts had different opinions on the influence of elevation and geology, with these differences attributable to geological differences between these regions. 5. Synthesis and applications. When formulated as priors in Bayesian analysis, expert opinion is useful for modifying or strengthening patterns exhibited by empirical data sets that are limited in size or scope. Nevertheless, the ability of an expert to extrapolate beyond their region of knowledge may be poor. Hence there is significant merit in obtaining information from local experts when compiling species' distribution models across several regions.

Elicitator : an expert elicitation tool for regression in ecology

Expert elicitation is the process of retrieving and quantifying expert knowledge in a particular domain. Such information is of particular value when the empirical data is expensive, limited, or unreliable. This paper describes a new software tool, called Elicitator, which assists in quantifying expert knowledge in a form suitable for use as a prior model in Bayesian regression. Potential environmental domains for applying this elicitation tool include habitat modeling, assessing detectability or eradication, ecological condition assessments, risk analysis, and quantifying inputs to complex models of ecological processes. The tool has been developed to be user-friendly, extensible, and facilitate consistent and repeatable elicitation of expert knowledge across these various domains. We demonstrate its application to elicitation for logistic regression in a geographically based ecological context. The underlying statistical methodology is also novel, utilizing an indirect elicitation approach to target expert knowledge on a case-by-case basis. For several elicitation sites (or cases), experts are asked simply to quantify their estimated ecological response (e.g. probability of presence), and its range of plausible values, after inspecting (habitat) covariates via GIS.

Comparison of three expert elicitation methods for logistic regression on predicting the presence of the threatened brush-tailed rock-wallaby petrogale penicillata

Numerous expert elicitation methods have been suggested for generalised linear models (GLMs). This paper compares three relatively new approaches to eliciting expert knowledge in a form suitable for Bayesian logistic regression. These methods were trialled on two experts in order to model the habitat suitability of the threatened Australian brush-tailed rock-wallaby (Petrogale penicillata). The first elicitation approach is a geographically assisted indirect predictive method with a geographic information system (GIS) interface. The second approach is a predictive indirect method which uses an interactive graphical tool. The third method uses a questionnaire to elicit expert knowledge directly about the impact of a habitat variable on the response. Two variables (slope and aspect) are used to examine prior and posterior distributions of the three methods. The results indicate that there are some similarities and dissimilarities between the expert informed priors of the two experts formulated from the different approaches. The choice of elicitation method depends on the statistical knowledge of the expert, their mapping skills, time constraints, accessibility to experts and funding available. This trial reveals that expert knowledge can be important when modelling rare event data, such as threatened species, because experts can provide additional information that may not be represented in the dataset. However care must be taken with the way in which this information is elicited and formulated.

Expert performance in sport and the dynamics of talent development

Research on expertise, talent identification and development has tended to be mono-disciplinary, typically adopting adopting neurogenetic deterministic or environmentalist positions, with an over-riding focus on operational issues. In this paper the validity of dualist positions on sport expertise is evaluated. It is argued that, to advance understanding of expertise and talent development, a shift towards a multi-disciplinary and integrative science focus is necessary, along with the development of a comprehensive multi-disciplinary theoretical rationale. Here we elucidate dynamical systems theory as a multi-disciplinary theoretical rationale for capturing how multiple interacting constraints can shape the development of expert performers. This approach suggests that talent development programmes should eschew the notion of common optimal performance models, emphasise the individual nature of pathways to expertise, and identify the range of interacting constraints that impinge on performance potential of individual athletes, rather than evaluating current performance on physical tests referenced to group norms.