Change blindness can cause mistaken eyewitness identification

The current study investigated the effects of change blindness and crime severity on eyewitness identification accuracy. This research, involving 717 subjects, examined change blindness during a simulated criminal act and its effects on subjects' accuracy for identifying the perpetrator in a photospread. Subjects who viewed videos designed to induce change blindness were more likely to falsely identify the innocent actor relative to those who viewed control videos. Crime severity did not influence detection of change; however, it did have an effect on eyewitness accuracy. Subjects who viewed a more severe crime ($500 theft) made fewer errors in perpetrator identification than those who viewed a less severe crime ($5 theft). This research has theoretical implications for our understanding of change blindness and practical implications for the real‐world problem of faulty eyewitness testimony.     

GC-MS and GC-IRD analysis of 2-, 3- and 4-methylmethamphetamine and 2-, 3- and 4-methylamphetamine

4-Methylmethamphetamine has been detected in samples submitted for analysis in several states throughout Australia. Six ring substituted methyl isomers of methamphetamine and amphetamine were synthesised and analysed. As the regioisomeric 2-, 3- and 4-methylmethamphetamine and 2-, 3- and 4-methylamphetamine have virtually identical mass spectra, the use of MS is an ineffective technique to discriminate between these closely related compounds. We set out to determine whether the regioisomers could be differentiated by a combination of GC-MS, acetyl derivatisation and GC-IRD. We demonstrate that the three isomers of methylmethamphetamine and methylamphetamine can be separated by GC, and a combination of acetyl derivatisation and vapour phase IR can identify the specific ring substituted compound.     

Evaluation of pediatric skull fracture imaging techniques

Radiologic imaging is crucial in the diagnosis of skull fracture, but there is some doubt as to whether different imaging modalities can accurately identify fractures present on a human skull. While studies have been performed to evaluate the efficacy of radiologic imaging at other anatomical locations, there have been no systematic studies comparing various CT techniques, including high resolution imaging with and without 3D reconstructions to conventional radiologic imaging in children, we investigated which imaging modalities: high-resolution CT scan with 3D projections, clinical-resolution CT scans or X-rays, best showed fracture occurrence in a pediatric human cadaver skull by having an expert pediatric radiologist examine radiologic images from fractured skulls. The skulls used were taken from pediatric cadavers ranging in age from 5 months to 16 years. We evaluated the sensitivity and specificity for the imaging modalities using dissection findings as the gold standard. We found that high-resolution CT scans with 3D projections and conventional CT provided the most accurate fracture diagnosis (single-fracture sensitivity of 71%) followed by X-rays (single-fracture sensitivity of 63%). Linear fractures outsider the region of the sutures were more identifiable than diastatic fractures, though the incidence of false positives was greater for linear fractures. In the two cases where multiple fractures were present on the same anatomical skull location, the radiologist was less likely to identify the presence of additional fractures than a single fracture. Overall, the high-resolution and clinical-resolution CT scans had the similar accuracy for detecting skull fractures while the use of the X-ray was both less accurate and had a lower specificity.     

Score-based likelihood ratios for handwriting evidence

Score-based approaches for computing forensic likelihood ratios are becoming more prevalent in the forensic literature. When two items of evidential value are entangled via a scorefunction, several nuances arise when attempting to model the score behavior under the competing source-level propositions. Specific assumptions must be made in order to appropriately model the numerator and denominator probability distributions. This process is fairly straightforward for the numerator of the score-based likelihood ratio, entailing the generation of a database of scores obtained by pairing items of evidence from the same source. However, this process presents ambiguities for the denominator database generation - in particular, how best to generate a database of scores between two items of different sources. Many alternatives have appeared in the literature, three of which we will consider in detail. They differ in their approach to generating denominator databases, by pairing (1) the item of known source with randomly selected items from a relevant database; (2) the item of unknown source with randomly generated items from a relevant database; or (3) two randomly generated items. When the two items differ in type, perhaps one having higher information content, these three alternatives can produce very different denominator databases. While each of these alternatives has appeared in the literature, the decision of how to generate the denominator database is often made without calling attention to the subjective nature of this process. In this paper, we compare each of the three methods (and the resulting score-based likelihood ratios), which can be thought of as three distinct interpretations of the denominator proposition. Our goal in performing these comparisons is to illustrate the effect that subtle modifications of these propositions can have on inferences drawn from the evidence evaluation procedure. The study was performed using a data set composed of cursive writing samples from over 400 writers. We found that, when provided with the same two items of evidence, the three methods often would lead to differing conclusions (with rates of disagreement ranging from 0.005 to 0.48). Rates of misleading evidence and Tippet plots are both used to characterize the range of behavior for the methods over varying sized questioned documents. The appendix shows that the three score-based likelihood ratios are theoretically very different not only from each other, but also from the likelihood ratio, and as a consequence each display drastically different behavior.     

Tattoo frequency and types among homicides and other deaths, 2007-2008: a matched case-control study

An estimated 25% of the US population aged 18 to 50 years has a tattoo, which have been associated with markers of high-risk behaviors including alcohol and drug use, violence, carrying weapons, sexual activity, eating disorders, and suicide. This study compares tattoo prevalence and type in a homicide population to those of an age-, race-, and sex-matched control group of nonhomicide deaths. The data for this study were abstracted from autopsy records maintained by the Jefferson County Alabama Coroner/Medical Examiner's Office for the years 2007 and 2008. Odds ratios and 95% confidence intervals for the association between homicide and tattoo presence and characteristics were calculated using conditional logistic regression. There was no association between tattoo presence and death by homicide; however, among blacks, memorial tattoos were significantly more common among homicides compared with other types of deaths (odds ratio, 2.50; 95% confidence interval, 1.10-5.68). The results of the current study suggest that specific types of tattoos, but not all tattoos, may be risk factors for homicide. Other factors, such as race and lifestyle, along with tattoos may need to be considered.     

Preparing for unwanted events: Instances of international political terrorism∗

The problems posed by international political terrorism, the likely performances of governments facing such challenges, and advisable preparatory coping strategies all benefit from systematic consideration of the experience, provided by practices and analyses of attempts to avoid and manage other forms of international crises. This paper pursues such a perspective to supplement more familiar approaches that use police and disaster amelioration points of departure.

The broader experience of international crises makes it clear that the problems are less ones of incident management than of prolonged competition for an image of political legitimacy and efficacy. Accordingly, recommendation for analysis and planning are made with emphasis on inventory of existent management capacities and decision processes, clarification of alternative political consequences, nonintrusive technology fixes, bargaining and indemnification policy options; and diagnostic gaming.     

The retina in forensic medicine: applications of ophthalmic endoscopy: the first 100 cases

The retina reflects a variety of diseases in the living patient. However, the retina is not routinely examined in deceased persons, and therefore it is unknown if routine retinal examination would be a useful adjunct to the forensic autopsy. To examine this issue, the retinae of routine medical examiner cases were examined utilizing an ophthalmic endoscope. The results of the first 100 examinations are reported. Specific attention was given to changes that reflected the postmortem interval, the development of petechiae as related to cardiopulmonary resuscitation, and the association of retinal hemorrhages to subconjunctival hemorrhages. The procedure was helpful in cases of suspected shaken baby syndrome, exsanguination, and carbon monoxide poisoning and in cases with sudden increased intracranial pressure (Terson syndrome). It appears that lividity patterns exist in the retina, and this may be potentially useful in determining body position after death. Some natural disease processes, such as hypertension, were also identified. Finally, the utility of the ophthalmic endoscope as a means of circumventing the problem of corneal clouding is discussed, and ideas for further research using this technology are presented.     

African American Oxford House residents: sources of abstinent social networks

The current study found that African American residents of Oxford House (OH) used Narcotics Anonymous (NA) at high rates, and that both OH and NA strongly contributed to abstinent social networks. Having siblings and other family members in one's network predicted substance use among network members, whereas spouses, parents, and children did not have an effect on the rate of substance use. These findings suggest that OH and NA may be effective sources of abstinent social support for African Americans recovering from substance abuse. However, family members are well represented in the support networks of African Americans in OH.