An Algorithm to Improve Test Answer Copying Detection Using the Omega Statistic

The omega (ω) statistic is reputed to be one of the best indices for detecting answer copying on multiple choice tests, but its performance relies on the accurate estimation of copier ability, which is challenging because responses from the copiers may have been contaminated. We propose an algorithm that aims to identify and delete the suspected copied responses through probability sampling and bootstrapping. In doing so, the bias in copier ability estimation will be determined and used to update the ability estimate for calculating the modified omega (ω^m), a new statistic based on the ω. The performance of ω^m and ω were compared in a Monte Carlo simulation study under 40 typical testing conditions (2 test lengths x 4 sample sizes x 5 levels of copying). In almost all conditions, the ω^m had the same or better controlled Type I error and higher power than ω. The increase in power was particularly eminent when the source's estimated ability was higher than the copier and when 20% or 30% of items were copied. These findings support the use of the ω^m as a replacement of ω to detect answer copying in multiple choice exams.     

The role and impact of mental simulation in design

Although theories of mental simulations have used different formulations of the premises of ‘thought experiments’, they can be fitted under a minimalist hypothesis stating that mental simulations are run under situations of uncertainty to turn that uncertainty into approximate answers. Three basic assumptions of mental simulations were tested by using naturalistic data from engineering design. Results from the design protocols showed (1) initial representations in mental simulation had higher than base‐rate uncertainty, (2) uncertainty in mental simulations were lowered after simulation runs, (3) resulting representations had more approximations than base‐rate or initial representations. Further, the reference to external representational systems (sketches and prototypes) was examined. It was found that prototypes had fewer technical/functional simulations compared to sketches or unsupported cognition. Although prototypes were associated with more approximation than unsupported cognition, the different external representation categories did not differ in information uncertainty. The results support the minimalist hypothesis of mental simulations. Copyright © 2008 John Wiley & Sons, Ltd.     

Disjunctivism, contextualism and the sceptical aporia

We know things that entail things we apparently cannot come to know. This is a problem for those of us who trust that knowledge is closed under entailment. In the paper I discuss the solutions to this problem offered by epistemic disjunctivism and contextualism. The contention is that neither of these theories has the resources to deal satisfactory with the problem.     

Full-screen ultrafast video modes over-clocked by simple VESA routines and registers reprogramming under MS-DOS

Fast full-screen presentation of stimuli is necessary in psychological research. Although Spitczok von Brisinski (1994) introduced a method that achieved ultrafast display by reprogramming the registers, he could not produce an acceptable full-screen display. In this report, the author introduces a new method combining VESA routine calling with registers reprogramming that can yield a display at 640 × 480 resolution, with a refresh rate of about 150 Hz.     

Evaluation of a Swedish version of the Job Stress Survey

The present study assesses and evaluates the psychometric properties of a Swedish version of the Job Stress Survey (JSS; Spielberger, 1991; Spielberger & Vagg, 1999). This instrument is constructed to measure generic sources of occupational stress encountered by employees in a wide variety of work settings, settings that often result in psychological strain. The JSS was administered to metal assembly industry workers and medical service personnel in northern Sweden (n= 1186). The exploratory factor analysis showed that there is a high similarity between the present Swedish version and the original American version. Internal reliabilities of the scales, as well as test-retest reliabilities were shown to be high, and concurrent validity, as examined by comparisons with the Perceived Stress Questionnaire Index (Levenstein et al., 1993) was found to be satisfactory. The consistency of these findings is discussed with particular focus on groups of employees, gender, and cross-cultural evaluations.     

Continuous and discontinuous drawing: high temporal variability exists only in discontinuous circling in young children

The authors studied whether the drawing variability in young children is best explicable by (a) demands on the explicit timing system, (b) an underdeveloped ability to control limb dynamics, or (c) both. The explicit timing demands were lower in continuous drawing in comparison with the discontinuous task. The authors manipulated limb dynamics by changing the number of joints involved, with line drawing requiring fewer joints than circle drawing. Results showed that young children had high temporal variability in discontinuous circling but not in other conditions. The authors argue that both explicit timing and dynamic complexity of limb control may be determinants of temporal consistency and may thus play an important role in the development of drawing and writing skills in children.     

Prevalence, course, incidence, and 1-year prediction of deliberate self-harm and suicide attempts in early Norwegian school adolescents

In this survey of early Norwegian school adolescents, the prevalence, course, and incidence of self-harm behavior with or without suicide intent were examined, in addition to predictors of self-harm for a 1-year follow-up period. Lifetime prevalence rates of self-harm without suicide intent and suicide attempts were 2.9% and 3.0%, respectively, while 1-year incidence rates were 3.6% and 1.7%, respectively. In multivariate analysis, five predictors significantly differentiated self-harmers from non-self-harming adolescents. Early school adolescents having frequent or intense suicidal ideation over an extended time period and attempting self-harm repeatedly with or without suicide intent should be identified and offered treatment.     

理解私人意图与交际意图的ERP证据

已有的意图理解神经成像研究大多关注理解单一个体私人意图的脑功能定位, 而较少涉及两个或更多人的社会性交际意图, 大脑区分私人意图和交际意图的动态时间过程尚不清楚。本研究记录了16名健康被试理解三种不同意图任务时的脑电成分。三种意图分别为: 1)私人意图; 2)交际意图; 3)物理意图。电生理学结果表明在大脑顶区, 私人意图的N250的峰值显著大于交际意图和物理意图。在晚期阶段(300~600 ms), 交际意图的晚期正成分(LPC)的平均波幅要显著大于私人意图和物理意图。在400~600 ms时, 私人意图的LPC的平均波幅要显著大于物理意图。本研究为理解私人意图和交际意图的动态加工过程提供了神经电生理学的初步证据。     

Psychopathy in a forensic sample – the factor structure of the PCL:SV in a Danish forensic sample

The research literature reveals an ongoing debate regarding the most appropriate conceptualization of psychopathic personality disorder. Specifically, it is discussed to what degree antisocial behavior is part of the conceptualization of the psychopathy construct and what constitutes the best factor model of the Psychopathy Checklist scales. The aim of the present study is to consider the underlying factor structure of the PCL:SV (Psychopathy Checklist Screening Version) in a Danish sample as well as considering the role of antisocial behavior in the psychopathy construct. Data from a Danish forensic patient sample (N = 225) was used and item response theory (IRT), aonfirmatory factor analyses (CFA) and structural equations model (SEM) analyses were carried out. Overall, the findings suggest appropriate item and model fit for the PCL:SV as well as superiority of the three‐factor model over the four‐factor model. The results are discussed in relation to the broader concept of personality disorder as well as clinical practice in regards to violence risk assessments and treatment of psychopathy.