Optimal and Most Exact Confidence Intervals for Person Parameters in Item Response Theory Models

The common way to calculate confidence intervals for item response theory models is to assume that the standardized maximum likelihood estimator for the person parameter θ is normally distributed. However, this approximation is often inadequate for short and medium test lengths. As a result, the coverage probabilities fall below the given level of significance in many cases; and, therefore, the corresponding intervals are no longer confidence intervals in terms of the actual definition. In the present work, confidence intervals are defined more precisely by utilizing the relationship between confidence intervals and hypothesis testing. Two approaches to confidence interval construction are explored that are optimal with respect to criteria of smallness and consistency with the standard approach.     

Number sense or working memory? The effect of two computer-based trainings on mathematical skills in elementary school

Research on the improvement of elementary school mathematics has shown that computer-based training of number sense (e.g., processing magnitudes or locating numbers on the number line) can lead to substantial achievement gains in arithmetic skills. Recent studies, however, have highlighted that training domain-general cognitive abilities (e.g., working memory [WM]) may also improve mathematical achievement. This study addressed the question of whether a training of domain-specific number sense skills or domain-general WM abilities is more appropriate for improving mathematical abilities in elementary school. Fifty-nine children (M_age = 9 years, 32 girls and 27 boys) received either a computer-based, adaptive training of number sense (n = 20), WM skills (n = 19), or served as a control group (n = 20). The training duration was 20 min per day for 15 days. Before and after training, we measured mathematical ability using a curriculum-based math test, as well as spatial WM. For both training groups, we observed substantial increases in the math posttest compared to the control group (d = .54 for number sense skills training, d = .57 for WM training, respectively). Whereas the number sense group showed significant gains in arithmetical skills, the WM training group exhibited marginally significant gains in word problem solving. However, no training group showed significant posttest gains on the spatial WM task. Results indicate that a short training of either domain-specific or domain-general skills may result in reliable short-term training gains in math performance, although no stable training effects were found in the spatial WM task.     

Statements

The churches today are called to confess anew their faith, and to repent for the times when Christians have remained silent in the face of injustice or threats to peace. The biblical vision of peace with justice for all, of wholeness, of unity for all God's people is not one of several options for the followers of Christ. It is an imperative in our time. (Peace and Justice Statement, WCC Sixth Assembly, Vancouver 1983)     

A dual-route perspective on eye movements of dyslexic readers

This study assessed eye movement abnormalities of adolescent dyslexic readers and interpreted the findings by linking the dual-route model of single word reading with the E-Z Reader model of eye movement control during silent sentence reading. A dysfunction of the lexical route was assumed to account for a reduced number of words which received only a single fixation or which were skipped and for the increased number of words with multiple fixations and a marked effect of word length on gaze duration. This pattern was interpreted as a frequent failure of orthographic whole-word recognition (based on orthographic lexicon entries) and on reliance on serial sublexical processing instead. Inefficiency of the lexical route was inferred from prolonged gaze durations for singly fixated words. These findings were related to the E-Z Reader model of eye movement control. Slow activation of word phonology accounted for the low skipping rate of dyslexic readers. Frequent reliance on sublexical decoding was inferred from a tendency to fixate word beginnings and from short forward saccades. Overall, the linkage of the dual-route model of single word reading and a model of eye movement control led to a useful framework for understanding eye movement abnormalities of dyslexic readers.     

Metamemory,distinctiveness, and event-related potentials in recognition memory for faces

A neglected topic in metamemory research is the ability of subjects to predict their own recognition performance for faces. We investigated whether subjects can make such judgments of learning (JOL) for unfamiliar faces and whether JOLs relate to facial distinctiveness, a powerful determinant of face recognition. One group of subjects made JOLs, and a second group rated the same faces for distinctiveness; subsequently, both groups tried to recognize these faces among new faces. There was significant prospective metamemory for faces that appeared to be based on facial distinctiveness. Both prospective metamemory and distinctiveness ratings related to long-lasting effects in event-related brain potentials (ERPs), closely resembling an ERP component that predicted face recognition. Therefore, the brain processes underlying JOLs, distinctiveness, and recognition memory for faces appear to be intimately related.     

Validierungskorrelate der inhaltsanalytisch erfaßten Leistungsmotivation guter und schwacher Schüler des dritten Schuljahres

Ohne ZusammenfassungHerrn Prof. Dr. Wolfgang Metzger zum 65. Geburtstag gewidmet.     

Application of Latent Semantic Analysis to Divergent Thinking is Biased by Elaboration

Scoring divergent‐thinking response sets has always been challenging because such responses are not only open‐ended in terms of number of ideas, but each idea may also be expressed by a varying number of concepts and, thus, by a varying number of words (elaboration). While many current studies have attempted to score the semantic distance in divergent‐thinking responses by applying latent semantic analysis (LSA), it is known from other areas of research that LSA‐based approaches are biased according to the number of words in a response. Thus, the current article aimed to identify and demonstrate this elaboration bias in LSA‐based divergent‐thinking scores by means of a simulation. In addition, we show that this elaboration bias can be reduced by removing the stop words (for example, and, or, for and so forth) prior to analysis. Furthermore, the residual bias after stop word removal can be reduced by simulation‐based corrections. Finally, we give an empirical illustration for alternate uses and consequences tasks. Results suggest that when both stop word removal and simulation‐based bias correction are applied, convergent validity should be expected to be highest.     

Mobbing at work and the development of post-traumatic stress disorders

Abstract

Psychosocial research on mobbing is currently being carried out in a number of countries, mainly in Europe. Mobbing is defined as an extreme social stressor at workplaces. In this article, its serious mental and psychosomatic health consequences are demonstrated and discussed. A factor analysis of symptom statistics collected through answers from a study representative of the entire Swedish workforce showed post-traumatic stress disorder (PTSD) as the plausible diagnosis. In addition, 64 patients subjected to mobbing at their work places are diagnosed with the co-operation of a rehabilitation clinic specializing in the treatment of chrome PTSD. The statistical analysis of these 64 diagnoses shows a severe degree of PTSD, with mental effects fully comparable with PTSD from war or prison camp experiences.     

Thought contents and cognitive functioning in motivational versus volitional states of mind

Do people who are about to make a decision differ from people who are about to enact a decision just made with respect to (1) the contents of their spontaneous stream of thought, and (2) aspects of cognitive functioning reflective of short-term memory? Subjects either made a choice between, or were assigned to, two available test materials allegedly designed to measure creativity and differentially suited to promote an individual's full creative potential. Subjects were, however, interrupted prior to or shortly after making this choice: In Study 1, they were asked to report on the thoughts they experienced during the time period just before the interruption; in Study 2, subjects were interrupted either before or after making a choice and were asked to recall lists of words designed to test memory span. The results of Study 1 confirmed our assumption that predecisional versus postdecisional streams of spontaneous thought reflectmotivational versusvolitional states of mind. That is, predecisional thought was preoccupied with incentive values of goal options, expectancy of performance outcomes, and metamotivational directives, whereas postdecisional thought was concerned with questions of how to implement the pursued goal. In Study 2, subjects in a motivational state of mind exhibited a greater memory span than subjects in a volitional state of mind. Since, in a further study, performance on arithmetic tasks did not improve for subjects in a motivational as opposed to a volitional state of mind, the results of Study 2 are understood as a state-dependent increase in receptivity with respect to incoming information. In interpreting the present findings, the characteristic features of motivational and volitional states are explicated. Furthermore, it is suggested that the dominating research tradition focusing on motivational problems (i.e., expectancy-value models) and the abandoned research tradition concerned with volitional problems (i.e., formation and implementation of an intent) should be integrated into a functional unit.