Some further studies on the effect of grouping elements of a visual stimulus on the cortical evoked potential

Grouping elements of a visual stimulus is shown to reduce the amplitude of the bipolar occipital evoked potential in three experiments. The first shows similar effects of grouping elements on the horizontal and vertical dimensions, combining in a nearly additive manner. The second shows a less stable grouping effect using irregularly spaced lines as stimuli. In the third experiment, small deviations from uniformity are seen to produce a reliable attenuation of the cortical evoked potential.     

Satisfied and Dissatisfied Students

Satisfaction toward school was assessed by means of a 60-item questionnaire and was related to measures of academic success, intellectual ability, social, class, and personal values. For the total sample of 258 high school juniors, there was no significant relation between their evaluation of school experiences and their achievement, as measured by standardized tests and teachers' grades. Teachers rated satisfied students as less impulsive and more responsible than average students. The teachers' ratings also revealed a marked positive bias in favor of girls. Extreme groups on the satisfaction measures were compared and tentative explanations are offered for some of the major differences.     

A responsibility model for the practice of professional school psychology: Psychoeducational therapy

This paper discusses from first-hand experience the need for, and development of, a program of psychoeducational therapy within a school system. Conditions in the schools that support and influence the therapy, as well as therapy characteristics, are considered in some detail. Reasons are delineated that make this a responsibility model of school psychology practice. The therapy program is part of a larger supporting thrust in intervention, features of which are briefly referred to.     

Counterconditioning and exposure-only in the treatment of specific (conditioned suppression) and generalized fear in rats

In Experiment 1 the conditioned suppression technique was used to condition specific fear, suppression of operent lever pressing for food to a discrete CS. The efficacy of four treatment conditions on fear reduction was evaluated. Counterconditioning in which exposure to the CS was contiguously paired with food was significantly less effective than noncontiguous CS exposure and food. An exposure-only effect was indicated by the superiority of all three treatments involving CS exposure (the above two plus a typical conditioned suppression extinction procedure) to treatment consisting of food only. The reverse counterconditioning effect and the exposure effect are consistent with current views that emphasize the centrality of aversive stimulus exposure in fear reduction. Experiment 2 investigated elimination of generalized fear produced by unsignalled, inescapable shocks in the lever-pressing apparatus. Two treatments (counterconditioning and exposure-only) were equally effective and they were superior to no exposure control treatment. The results of the two experiments reinforce recent attempts toward a reevaluation of the role of anxiety-competing responses in elimination of fear.     

Lower bounds for the reliability of the total score on a test composed of non-homogeneous items: I: Algebraic lower bounds

Let Σ _x be the (population) dispersion matrix, assumed well-estimated, of a set of non-homogeneous item scores. Finding the greatest lower bound for the reliability of the total of these scores is shown to be equivalent to minimizing the trace of Σ _x by reducing the diagonal elements while keeping the matrix non-negative definite. Using this approach, Guttman's bounds are reviewed, a method is established to determine whether his λ₄ (maximum split-half coefficient alpha) is the greatest lower bound in any instance, and three new bounds are discussed. A geometric representation, which sheds light on many of the bounds, is described. Present affiliation of the second author: Department of Statistics, University of Nigeria (Nsukka Campus). Work on this paper was carried out while on study leave in Aberystwyth.     

Period analytic algorithms for the estimation of selected spectral properties of short segments of EEG data

The accuracy and computational speed of three algorithms (spectral analysis, period analysis, and period amplitude analysis) for the extraction of spectral estimates from time-series data are empirically evaluated in the context of a neuropsychological experiment that requires estimates of power in the standard electroencephalographic frequency bands.     

Duration of unemployment and psychological well-being in young men and women

Previous research has typically failed to support the plausible expectation that lower psychological well-being accompanies longer unemployment. Two cohorts of recent school-leavers were interviewed over two years, and five data sets were available for investigation. Measures of both psychological distress and self-esteem were found to be uncorrelated with duration of unemployment for young men. For young women no relationships with self-esteem were observed, and in one cohort longer female unemployment was associated with lower distress. This was shown to be due to women's withdrawal from the labour market because of pregnancy and child care. It is suggested that the expected association between duration and well-being may be restricted to older samples and longer periods out of work.     

Note on the squared multiple correlation as a lower bound to communality

It is demonstrated that the squared multiple correlation of a variable with the remaining variables in a set of variables is a function of the communalities and the squared canonical correlations between the observed variables and common factors. This equation is shown to imply a strict inequality between the squared multiple correlation and communality.