Modellierung von Fehlkonzepten in einer algebraischen Wissensstruktur

An extension of the theory of knowledge spaces by Doignon &; Falmagne (1985) is presented that tries to account for subjects’ typical errors and wrong answers. This extension concerns two major points: The usual dichotomous item format (right/wrong) is generalized to polytomous response categories, and the theoretical structure (knowledge, skills, misconceptions) is clearly separated from the empirical structure (observable solution behavior, subject’s responses). Using examples from a set of questions about properties of simple electric circuits the general method is demonstrated. Axioms of an algebraic structure known as “information system” (Scott, 1982) are shown to provide an appropriate characterization of the theoretical domain. The structural properties of the data, on the other hand, can be derived from assumptions about the influence of knowledge and misconceptions on specific answers for a set of questions.     

On counteradaptation

Often adaptation to artificially altered stimulation takes place because veridical stimulation that produces the same perceptual property that is produced by the altered stimulation is also received. In these cases, an assimilation of the two perceptual processes produced by the two different stimulations (the altered and the veridical) is supposed to be responsible for the adaptation that is achieved. This hypothesis, which was formulated by Wallach and Karsh (1963), would be confirmed by demonstrating a modification of the perceptual process produced by veridical stimulation rather than the one produced by the altered stimulation. We demonstrated this by having S observe in the dark for 20 min a luminous figure that objectively expanded as it moved toward S and contracted as it moved away. But instead of testing for changes in size perception as such, we tested for a change in the relation between accommodation and convergence on the one hand and registered distance on the other. In one experiment, such a change was measured by obtaining estimates of perceived size and depth before and after the adaptation period. Highly significant changes of size and significantly greater changes of stereoscopic depth were obtained. Inasmuch as stereoscopic vision was totally absent from the adaptation conditions, the change in stereoscopic depth that was larger than the size change can only be ascribed to a change in registered distance. In another experiment, we tested for a change in distance by having S point from the side to a vertical line, before and again after the adaptation period, under conditions where only accommodation and convergence could serve as distance cues. Significant changes in the pointing distance were measured, indicating more directly a change in the relation between these oculomotor adjustments and perceived distance. We propose the term counteradaptation for such modification of a perceptual process away from veridicality.     

Primate learning tasks reveal strong impairments in patients with presenile or senile dementia of the Alzheimer type

Eight subjects with the likely diagnosis of presenile or senile dementia of the Alzheimer type were tested on two frequently used primate learning tasks: a concurrent object discrimination task and a delayed non-match-to-sample task. In addition, various tests for cognitive, mnemonic, perceptual, and language functions were applied. The results suggest a severe decline of the Alzheimer subjects in all measures when compared with 10 control subjects matched for age, gender, and education. The two animal learning tasks revealed strong impairments, thus demonstrating a high sensitivity for the detection and assessment of human amnesic disorders. Implications of these findings for human neuropsychological, and especially comparative neuropsychological, research are discussed.     

Optimizing Exposure Therapy for Pathological Health Anxiety: Considerations From the Inhibitory Learning Approach

Exposure therapy has demonstrated its efficacy in the treatment of pathological health anxiety—however, psychotherapy research reveals that many patients do not show a clinically significant change. Therefore, improvements are necessary to optimize psychotherapy for pathological health anxiety. Most treatment rationales refer to habituation during exposure as the central mechanism of change. However, there is evidence that extinction learning is mediated by inhibitory learning processes. Targeting these processes may help to improve treatment outcomes in pathological health anxiety. The aim of this review was to adapt, from the inhibitory learning approach and empirical findings, the most promising strategies for the exposure-based treatment of pathological health anxiety. The exposure-optimizing strategies adapted are expectancy violation, combination, variability in contexts and stimuli, affect labeling, and removal of safety signals. A case example illustrates how to implement these methods for patients with pathological health anxiety.     

Development and validation of a brief self-report measure of trauma exposure: the Trauma History Screen

Although information about individuals' exposure to highly stressful events such as traumatic stressors is often very useful for clinicians and researchers, available measures are too long and complex for use in many settings. The Trauma History Screen (THS) was developed to provide a very brief and easy-to-complete self-report measure of exposure to high magnitude stressor (HMS) events and of events associated with significant and persisting posttraumatic distress (PPD). The measure assesses the frequency of HMS and PPD events, and it provides detailed information about PPD events. Test-retest reliability was studied in four samples, and temporal stability was good to excellent for items and trauma types and excellent for overall HMS and PPD scores. Comprehensibility of items was supported by expert ratings of how well items appeared to be understood by participants with relatively low reading levels. In five samples, construct validity was supported by findings of strong convergent validity with a longer measure of trauma exposure and by correlations of HMS and PPD scores with posttraumatic stress disorder (PTSD) symptoms. The psychometric properties of the THS appear to be comparable or better than longer and more complex measures of trauma exposure.     

The role of encoding strategies in the verbal memory performance in patients with schizophrenia

Background. Verbal learning and memory is often compromised in patients with schizophrenia who prefer encoding words in order of their presentation (serial clustering) rather than using semantic categories (semantic clustering). Method. One hundred and four in‐patients with schizophrenia were assessed twice with the California Verbal Learning Test. Results. Patients showed significantly less semantic than serial clustering at both assessment times. Usage of encoding strategies were not stable over time. An increase in semantic clustering improved recall and recognition performance. Conclusions. Patients with schizophrenia should be taught to use the more effective encoding strategy of semantic clustering in order to improve their memory performance.     

The importance of context information for the spatial specificity of gaze cueing

In three experiments, we investigated the spatial allocation of attention in response to central gaze cues. In particular, we examined whether the allocation of attentional resources is influenced by context information—that is, the presence or absence of reference objects (i.e., placeholders) in the periphery. On each trial, gaze cues were followed by a target stimulus to which participants had to respond by keypress or by performing a target-directed saccade. Targets were presented either in an empty visual field (Exps. 1 and 2) or in previewed location placeholders (Exp. 3) and appeared at one of either 18 (Exp. 1) or six (Exps. 2 and 3) possible positions. The spatial distribution of attention was determined by comparing response times as a function of the distance between the cued and target positions. Gaze cueing was not specific to the exact cued position, but instead generalized equally to all positions in the cued hemifield, when no context information was provided. However, gaze direction induced a facilitation effect specific to the exact gazed-at position when reference objects were presented. We concluded that the presence of possible objects in the periphery to which gaze cues could refer is a prerequisite for attention shifts being specific to the gazed-at position.     

Three Assistants on Boltzmann

The three demi-articles presented here would give a brief biographical account of Ludwig Boltzmann’s life plus some details about his Vienna laboratories first in the 1860’s in the Erdberg and second in Türkenstrasse from 1894. Josef Nabl’s account discusses J. J. Thomson’s Laboratory in Cambridge, which allows a provisional comparison between two different largely contemporary institutes. Nabl’s second letter also mentions Lord Kelvin’s late rejection of the kinetic gas theory of Maxwell and Boltzmann, rejection which on top of the negative attitude of Mach, Zermelo, and Poincaré probably did not benefit Boltzmann’s state of mind and may have contributed to the extreme character of Boltzmann’s anti-philosophical counterattack starting in 1903. This revised version was published online in June 2006 with corrections to the Cover Date.