Threatened leadership and intergroup competition

In this paper three experimental studies are reported in which leaders were given a choice between intergroup competition or -cooperation under the threat of being deposed or not by their followers. Consistent with our predictions, threatened leaders were more likely to opt for intergroup competition, especially when their group was internally divided and when they had a strong bargaining position. However, they only chose intergroup competition, regardless of their chances of bringing the intergroup conflict to a successful conclusion, when their tenure of power was very precarious.     

Formal and informal classroom settings: Effects on hyperactivity

The behavior of hyperactive children was compared to controls in two different classroom settings. One setting (Informal) involved choice and variety of tasks; the other setting (Formal) involved teacher specification of a small number of tasks. As assessed by a composite observational measure of hyperactivity, there were significant differences between the hyperactive and control groups in the Formal but not in the Informal setting. Analyses of five individual categories of hyperactive behavior showed that, with one exception, the hyperactive group tended to display higher frequencies of behavior than did controls in both settings. For two of the categories, the difference between the groups was significantly larger in the Formal than in the Informal setting. Finally, a modified observational code was suggested that differentiated hyperactives from controls equally in the two settings.     

Teachers' norms and teacher-parent agreement on the Missouri children's behavior checklist

Normative data are reported for a 68-item teacher's form of the Missouri Children's Behavior Checklist (MCBC-T). Sex differences comparable to those found in parents' ratings were found but teachers' average ratings were significantly lower than parents' ratings. The correlations between teachers' and parents' ratings are comparable to those found in the literature and provide evidence for convergent and discriminant validity of the MCBC scales.     

Relative alpha desynchronization and synchronization during perception of music

Relative desynchronization (ERD) and synchronization (ERS) of the 8–10 Hz and 10–12 Hz alpha freqency bands elicited by music were studied in ten musically untrained right-handed subjects. The subjects listened to two five-minute musical excerpts representing two different musical genres, popular and classical, presented both foward and backward. ERD/ERS of the two alpha frequency bands was examined during the first four minutes of stimulus presentation using one-minute time windows. The results demonstrated that both the 8–10 Hz and the 10–12Hz frequency band exhibited reactivity to musical stimuli. The responses of the 8–10Hz and 10–12 Hz alpha frequency bands were dissimilar, dymanic and dependent on both time and stimulation type. The dynamics of these changes over time may explain some discrepancies in earlier EEG studies during listening to music.     

A study of the classification capabilities of neural networks using unsupervised learning: A comparison withK-means clustering

Several neural networks have been proposed in the general literature for pattern recognition and clustering, but little empirical comparison with traditional methods has been done. The results reported here compare neural networks using Kohonen learning with a traditional clustering method (K-means) in an experimental design using simulated data with known cluster solutions. Two types of neural networks were examined, both of which used unsupervised learning to perform the clustering. One used Kohonen learning with a conscience and the other used Kohonen learning without a conscience mechanism. The performance of these nets was examined with respect to changes in the number of attributes, the number of clusters, and the amount of error in the data. Generally, theK-means procedure had fewer points misclassified while the classification accuracy of neural networks worsened as the number of clusters in the data increased from two to five.Acknowledgements: Sara Dickson, Vidya Nair, and Beth Means assisted with the neural network analyses.     

Interference in the perceived segregation of equal-luminance element-arrangement texture patterns

Perceived segregation in element-arrangement patterns composed of squares of equal size and luminance, but of two different hues, was investigated in two experiments. Element-arrangement patterns consist of two types of elements, arranged in alternating vertical stripes in the top and bottom regions and in a checkerboard pattern in the center region. Perceived segregation of the striped and checkerboard regions decreased with increasing luminance of the interspaces between the squares, a high-luminance surround, and the increased spacing of the squares. When the luminance of the horizontal interspaces was increased, the decrease in perceived segregation was greater than that when the luminance of the vertical interspaces was increased. Two explanations of the interference of the interspace luminance are discussed. One explanation is in terms of inhibitory interactions among cortical filters tuned to spatial frequency and orientation. A second explanation is in terms of interference with preattentive grouping processes.     

Discomfort with space and motion: A possible marker of vestibular dysfunction assessed by the situational characteristics questionnaire

Space and motion discomfort (SMD) refers to the situational specificity of symptoms occurring in some patients with vestibular dysfunction, such as those with balance disorders and some with panic disorder. SMD occurs in situations characterized by inadequate visual or kinesthetic information for normal spatial orientation. We report the results of two studies of the construct validity of the Situational Characteristics Questionnaire (SitQ), which has two subscales, both of which measure SMD: the SMD-I and SMD-II. In Study 1, the SitQ was administered to members of a self-help group for balance disorders, a psychiatric sample consisting of patients with panic disorder, nonpanic anxiety disorders, depression, and a sample of normals. SMD levels were the highest in the self-help balance group, next to the highest in the panic groups, and lowest in the remaining groups. In Study 2, the SitQ was administered to otolaryngological patients with vestibular dysfunction and to patients with hearing loss. SMD levels were higher in the vestibular patients. Data on internal consistency, test-retest reliability, and convergent and discriminant validity are presented. The SitQ, particularly the SMD-II, is recommended for quantifying space and motion discomfort in patients with anxiety and/or balance disorders.Study 1 was funded by MH 40757. Study 2 was funded by a grant from the Upjohn Company and MH 19816.     

Experiences in the diagnosis and treatment of polyneuropathies in patients with malignant monoclonal gammopathy

4 patients are reported having monoclonal gammopathies, who clinically exhibited a sensomotoric polyneuropathy being progressive during some years. The EMG showed axional failure and secondary demyelisation. In two of the patients an IgG-type multiple myeloma has been revealed, while in the other two ohnes an increase of abnormal IgM-mIg could be demonstrated. In all patients the liquor protein was found increased and the appropriate mIg has been found in the liquor. Immunohistochemically the appropriate immunoglobulins could be demonstrated on the peripheral nerve by means of immunofluorescence method. Electron microscopical studies of nerval biopsies supported the diagnosis of mIg-associated polyneuropathy. References to diagnostics and treatment of mIg-associated polyneuropathy are done.