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

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

Likelihood-Based Clustering of Meta-Analytic SROC Curves

Meta-analysis of diagnostic studies experience the common problem that different studies might not be comparable since they have been using a different cut-off value for the continuous or ordered categorical diagnostic test value defining different regions for which the diagnostic test is defined to be positive. Hence specificities and sensitivities arising from different studies might vary just because the underlying cut-off value had been different. To cope with the cut-off value problem interest is usually directed towards the receiver operating characteristic (ROC) curve which consists of pairs of sensitivities and false-positive rates (1-specificity). In the context of meta-analysis one pair represents one study and the associated diagram is called an SROC curve where the S stands for “summary”. In meta-analysis of diagnostic studies emphasis has traditionally been placed on modelling this SROC curve with the intention of providing a summary measure of the diagnostic accuracy by means of an estimate of the summary ROC curve. Here, we focus instead on finding sub-groups or components in the data representing different diagnostic accuracies. The paper will consider modelling SROC curves with the Lehmann family which is characterised by one parameter only. Each single study can be represented by a specific value of that parameter. Hence we focus on the distribution of these parameter estimates and suggest modelling a potential heterogeneous or cluster structure by a mixture of specifically parameterised normal densities. We point out that this mixture is completely nonparametric and the associated mixture likelihood is well-defined and globally bounded. We use the theory and algorithms of nonparametric mixture likelihood estimation to identify a potential cluster structure in the diagnostic accuracies of the collection of studies to be analysed. Several meta-analytic applications on diagnostic studies, including AUDIT and AUDIT-C for detection of unhealthy alcohol use, the mini-mental state examination for cognitive disorders, as well as diagnostic accuracy inspection data on metal fatigue of aircraft spare parts, are discussed to illustrate the methodology.     

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.     

The futility of explicit knowledge of a sequence of tasks

In an experiment that combined the task-shifting methodology with a serial reaction-time task, three groups of participants had to shift among a set of four tasks that were arranged in regular sequences of length eight. Two groups of participants were given explicit knowledge about the sequence of tasks. To ensure that the knowledge of the sequence was referred to in each trial, one group was asked to verbalise the forthcoming task (verbalisation group), whereas the other group had to detect trials that deviated from the learned sequence (detection group). Participants of a control group were given no information about the sequence of tasks. In addition, for all experimental groups in half of the blocks of trials external precues were presented which indicated the forthcoming task. The control group exhibited substantial task-shifting costs that were greatly reduced by the presentation of precues. Participants of the explicit-knowledge groups showed no indication that explicit knowledge resulted in advance preparation of the forthcoming task. In addition, the effect of the precues depended on the secondary task that had to be performed on the basis of explicit knowledge. Whereas for the detection group precues reduced shift costs to the same degree as for the control group, the verbalisation group showed no precueing benefits at all.     

Relationships between restrictive mother-child interactions and anxiety of the child

Abstract

The “two-process model” postulates that there are specific associations between patterns of parental child-rearing styles and the development of the child's anxiety and coping dispositions. Besides parameters of parental feedback to the child, this model considers support and restriction to be the central dimensions of child-rearing behavior. The present study aims at assessing behavioral indicators for restriction. For this purpose, the working and intervention behavior of 47 mothers and their ten- to 13-year-old children was observed and registered during a 15-minute period of common problem-solving (putting together a difficult puzzle-like cube). In order to register processes of problem-oriented cooperation between mother and child, transitional probabilities between defined state and event classes were analyzed. Based on the theoretical definition of the child-rearing style “restrictio”, hypotheses concerning the significance of variable transitional probabilities are formulated and tested regarding their correspondence with anxiety-related characteristics of the child.     

Negative perfectionism increases the risk of fatigue following a period of stress

Abstract

There is a considerable amount of research concerning (he relationship between psychological variables and the postoperative outcome of surgery. However, little attention has been paid to the potential influence of psychological factors on infra-operative variables, most notably on anaesthetic requirement. The present study investigates the influence of surgery-related trail and slate anxiety as well as of dispositional and surgery-related actual coping on several indicators of intra- and postoperative adjustment. In addition, a possible mediating effect of stress-induced analgesia on the relationships between anxiety, coping, and intraoperative anaesthetic requirements was evaluated. Sixty-one patients undergoing elective lumbar iniclcotomy completed questionnaires regarding anxiety and coping variables one day before surgery. Intraoperative adjustment was assessed by measuring EEG-controlled anaesthetic requirements for induction and maintenance of anaesthesia, β-endorphin plasma concentration was collected preoperatively in the induction room. Postoperative outcome was assessed on the third day after surgery by questionnaires regarding pain experience, physical condition and emotional state. For preoperative anxiety as well as vigilant coping behaviour, there were opposite relationships with subjective measures of adjustment (e.g. self-reported postoperative pain experience), on the one side, and objective measures on the other (e.g., intraoperative anaesthetic requirement). Stress-induced analgesia was found for the subgroup of high-anxious patients. The results indicate that psychological programmes aimed at facilitating patients' perioperative adjustment should consider the different effects of anxiety and coping on subjective and objective measures.     

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.     

Number Judgment of Postage Stamps: A Contribution to the Psychology of Social Norms

PBI teems with unanswered questions regarding location, relative position, size, color, shape, movement, magnification, and what, precisely, is being observed. A novel experimental design is suggested which might permit sustained observation of PBI with use of facilitating flicker with a quasi-moving but motionless stimulus and a stationary eye.     

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.     

Alcohol and aggression without consumption. Alcohol cues, aggressive thoughts, and hostile perception bias

Researchers and the lay public have long known of a link between alcohol and aggression. However, whether this link results from alcohol's pharmacological effects or is merely an artifact of the belief that alcohol has been consumed (i.e., placebo effect) has been debated. The current experiments examined the propensity for alcohol-related cues to elicit aggressive thoughts and hostile perceptions in the absence of alcohol or placebo consumption. In Experiment 1, participants made faster lexical decisions concerning aggression-related words following alcohol-related primes compared with neutral primes. In Experiment 2, participants who first were exposed to alcohol advertisements subsequently rated the behavior of a target person as more hostile than participants who initially viewed control advertisements. Furthermore, this effect was largest among participants who most strongly associated alcohol and aggression. Findings are discussed in terms of semantic network theory and links in memory between alcohol and its anticipated effects.