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131.
A 2-step approach for obtaining internal consistency reliability estimates with item-level missing data is outlined. In the 1st step, a covariance matrix and mean vector are obtained using the expectation maximization (EM) algorithm. In the 2nd step, reliability analyses are carried out in the usual fashion using the EM covariance matrix as input. A Monte Carlo simulation examined the impact of 6 variables (scale length, response categories, item correlations, sample size, missing data, and missing data technique) on 3 different outcomes: estimation bias, mean errors, and confidence interval coverage. The 2-step approach using EM consistently yielded the most accurate reliability estimates and produced coverage rates close to the advertised 95% rate. An easy method of implementing the procedure is outlined. 相似文献
132.
Boredom proneness and sleep disorders as predictors of adult attention deficit scores 总被引:1,自引:0,他引:1
This study examined the extent to which boredom proneness and sleep disturbances were related to attention deficit scores in college-aged adults. In a sample of 148 college students, Attention scores on the Adult Behavior Checklist were best predicted by Boredom Proneness (BP) subscale scores, which assess one's inability to maintain internal stimulation and feelings of constraint, and scores on the Epworth Daytime Sleepiness Scale and Athens Insomnia Scale (R2 = .57). Hyperactivity scores were best predicted by the BP subscales, which assess one's need for a stimulating environment, the perception of time passing slowly, and feelings of constraint, and the Epworth Scale (R2 = .51). The findings contribute to the understanding of the symptomatology of attention deficit in adults and provide further evidence of the validity of this measure. 相似文献
133.
In modern digital applications, users often interact with virtual representations of themselves or others, called avatars. We examined how these avatars and their perspectives influence stimulus–response compatibility in a Simon task. Participants responded to light/dark blue stimuli with left/right key presses in the presence of a task-irrelevant avatar. Changes in stimulus–response compatibility were used to quantify changes in the mental representation of the task and perspective taking toward this avatar. Experiments 1 and 2 showed that perspective taking for an avatar occurred in orthogonal stimulus–response mappings, causing a compatibility effect from the avatar’s point of view. In the following two experiments we introduced a larger variety of angular disparities between the participant and avatar. In Experiment 3, the Simon effect with lateralized stimulus positions remained largely unaffected by the avatar, pointing toward an absence of perspective taking. In Experiment 4, after avatar hand movements were added in order to strengthen the participants’ sense of agency over the avatar, a spatial compatibility effect from the avatar’s perspective was observed again, and hints of the selective use of perspective taking on a trial-by-trial basis were found. Overall, the results indicate that users can incorporate the perspective of an avatar into their mental representation of a situation, even when this perspective is unnecessary to complete a task, but that certain contextual requirements have to be met. 相似文献
134.
Craig M 《Stress (Amsterdam, Netherlands)》2001,4(3):205-213
Our current understanding into the role of stress in unexplained recurrent miscarriages comes from two different research strategies. The majority of research has examined the role of psychological support within this patient population. This support has been provided in a number of ways ranging from weekly interviews with a psychiatrist or gynaecologist and or visual re-assurance in the form of ultrasound scans. A comparison of psychological support with an absence of such intervention has found differences in successful pregnancy outcome varying from as great as 84 versus 26%, respectively. It has been assumed that psychological support reduces the miscarriage rate by reducing “stress”within this patient population. In addition it provides indirect support for a role of stress in the aetiology of unexplained recurrent miscarriage. Other studies have attempted to directly assess the effect of personality characteristics on miscarriage rate; these studies have yielded conflicting results.The mechanism by which stress may be causal in the aetiology of unexplained recurrent miscarriage has not been examined in humans. Animal studies, however, have found that psychological distress can alter immune parameters that may be intricately involved with implantation. These parameters include an elevation of the “abortive” cytokine TNF-a and a reduction in the “anti-abortive” cytokine TGF-P2. Cells that are involved in the release of TNF-a at the feto-maternal interface include T cells, macrophages and mast cells.Mechanisms through which stress may act on these cells are explored and an integrated model is postulated. 相似文献
135.
In two experiments, we examined whether voluntary and reflexive saccades shared a common fixation disengagement mechanism. Participants were required to perform a variety of tasks, each requiring a different level of information processing of the display prior to execution of the saccade. In Experiment 1, participants executed either a prosaccade or an antisaccade upon detecting a stimulus array. In Experiment 2, participants executed a prosaccade to a stimulus array only if the array contained a target item. The target could be a line (easy search) or a digit (difficult search). The critical manipulation in both experiments was the relative timing between the removal of the fixation stimulus and the onset of the stimulus array. In both experiments, it was found that saccadic latencies were shortest when the fixation stimulus was removed before the onset of the stimulus array--a gap effect. It was concluded that reflexive and voluntary saccades share a common fixation disengagement mechanism that is largely independent of higher level cognitive processes. 相似文献
136.
Craig RJ 《Journal of personality assessment》1999,73(2):290-304
Test results from the MCMI have been ruled admissible in court for a variety of clinical and forensic issues. This article addresses MCMI issues such as the test's applicability and admissibility of test results in forensic evaluations, test administration, test scoring, malingering and deception, prediction and diagnosis of behavior, reliability, validity, operating characteristics and diagnostic efficiency statistics, and use of computer-assisted interpretation of test results for forensic presentation. Recommendations are suggested for dealing with each of these issues in a forensic context. 相似文献
137.
Zusammenfassung. Das hier vorgestellte Modell lernt graduell, Planungsaufgaben aus der Klasse der Maschinenbelegungsprobleme (job-shop-scheduling problems) zu lösen. Mit Hilfe des Chunking-Mechanismus von Soar wird episodisches Wissen über die Belegungsreihenfolge von Aufträgen auf Maschinen memoriert. Bei der Entwicklung des Modells wurden zahlreiche qualitative (z. B. Transfereffekte) und quantitative Befunde (z. B. Bearbeitungszeiten) aus einer früheren empirischen Untersuchung berücksichtigt. In einer Validierungsstudie wurden dieselben Aufgaben von 14 Probanden und dem Modell bearbeitet. Die Passung von Simulationsdaten und empirischen Ergebnissen fiel insgesamt gut aus. Allerdings löst das Modell die Aufgaben schneller und zeigt auch einen etwas besseren Lernverlauf als die Probanden. Das Modell liefert eine Erklärung für das Rauschen, das typischerweise bei Bearbeitungszeiten zu beobachten ist: es handelt sich um erworbenes Wissen, das mehr oder weniger gut und auch unterschiedlich häufig auf neue Situationen übertragen wird. Der Lernverlauf der Probanden entspricht nur für aggregierte Daten einer Potenzfunktion (power law). Der vorgestellte Mechanismus zeigt, wie ein symbolisches Modell der Informationsverarbeitung graduelle Verhaltensänderungen generiert und wie der offensichtliche Erwerb allgemeiner Prozeduren ohne explizites Lernen von deklarativen Regeln erfolgen kann. Es wird nahegelegt, daß es sich hier um die Modellierung einer Form impliziten Lernens handelt. Summary. The model presented here gradually learns how to perform a job-shop scheduling task. It uses Soar's chunking mechanism to acquire episodic memories about the order to schedule jobs. The model was based on many qualitative (e.g., transfer effects) and quantitative (e.g., solution time) regularities found in previously collected data. The model was tested with new data where scheduling tasks were given to the model and to 14 subjects. The model generally fit these data with the restrictions that the model performs the task (in simulated time) faster than the subjects, and its performance improves somewhat more quickly than the subjects' performance. The model provides an explanation of the noise typically found in problem solving times - it is the result of learning actual pieces of knowledge that transfer more or less to new situations but rarely by an average amount. Only when the data are averaged (i.e., over subjects) does the smooth power law appear. This mechanism demonstrates how symbolic models can exhibit a gradual change in behavior and how the apparent acquisition of general procedures can be performed without resorting to explicit declarative rule generation. We suggest that this may represent a type of implicit learning. 相似文献
138.
139.
140.
Luc Steels 《Kognitionswissenschaft》1999,8(4):143-150
Linguistics must again concentrate on the evolutionary nature of language, so that language models are more realistic with respect to human natural languages and have a greater explanatory force. Multi-agent systems are proposed as a possible route to develop such evolutionary models and an example is given of a concrete experiment in the origins and evolution of word-meaning based on a multi-agent approach. 相似文献