Interference with memory for lifted weight

An adaptation-level model for memory was tested by interpolating different weights between the standard and comparison weights. The results suggest that the model should be modified to account for the general tendency to use alternative categories of judgment with equal frequency. In terms of the modified model, memory for the standard shifts toward the value of the interfering stimulus, the magnitude of shift being proportional to the difference between the interfering stimulus and the value the memory would otherwise have had.     

Potentiation of the pressor response to stress by tolbutamide in dogs

Tolbutamide has previously been shown to amplify the pressor effects of “exogenous” catecholamines in conscious dogs, possibly due to sensitization of the α₁-adrenoreceptor-mediated vasoconstriction. The objective of this study was to examine if tolbutamide also amplifies the pressor effects of “endogenous” catecholamines released during psychological stress (classical Pavlovian aversive conditioning). Experiments were conducted in β-adrenoreceptor-blocked (propranolol, 1 mg/kg, i.v.) conscious dogs (n=4) trained in classical aversive conditioning. Conditioning was accomplished by following a tone (CS+) with a 1/2 second shock; another tone (CS-) was not followed by any shock and served as control. With saline pretreatment, aversive conditioning (i.e., CS+) increased mean arterial pressure (MAP) only by approximately 4.7% when compared to CS-, whereas with tolbutamide (45 mg/kg, i.v.) pretreatment, the increase in MAP induced by CS+ beyond what was induced by the CS- (approximately 6.2%) was significantly (p<0.05) larger than that with saline pretreatment. In isolated canine femoral arterial segments (n=4), the vasoconstrictor effect of phenylephrine (an α₁-agonist) at 5×10^?6M (which was the EC₅₀ value) was amplified by 2×10^?2M of tolbutamide from 54.0±2.0% to 66.9±2.1%. In conclusion, tolbutamide amplifies the pressor effects of “endogenous” catecholamines in conscious dogs, possibly by sensitization of the α₁-adrenoreceptor-mediated vasoconstriction. This mechanism of action is novel and has not been reported with other agents.     

Contributors to the Appraisal of Major Life Changes: Gender, Perceived Controllability, Sensation Seeking, Strain, and Social Support

This study investigated relationships between the appraisal of life events and gender, locus of control, social support, strain, and sensation seeking. In group sessions, undergraduate males and females completed self-report measures assessing life events appraisals and self-report measures for the above individual differences. Analyses supported the notion that a range of these variables, previously shown to serve as moderators of life stress, are significantly related to the appraisals of life events. Moreover, in addition to the gender differences obtained for the perception of life events, gender was found to influence several associations between the individual differences and life events appraisal.     

A comparison of two multidimensional health locus of control instruments

This study examined the factor structure, internal consistency reliability, and construct validity of the multidimensional health locus of control (MHLC) instruments developed by K.A. Wallston, B.S. Wallston, and DeVellis (1978) and Lau (Lau, 1982; Lau & Ware, 1981). Both measures were administered to a sample of Veterans Administration (VA) medical outpatients (N = 181). Only minimal evidence of convergence was found between corresponding scales of the two MHLC instruments. Low convergent validity appears attributable to the poor internal consistency reliability of the Lau-Ware subscales. Moreover, results of factor analysis largely supported the a priori factor structure of the K.A. Wallston et al. (1978) MHLC instrument but failed to support the factor structure of the Lau-Ware instrument. Health locus of control (HLC) dimensions that emerged from simultaneous factor analysis of both instruments were most consistent with a three-dimensional typology (i.e., Personal Control, Professional Control, and Chance) rather than the four-dimensional typology proposed by Lau (Lau, 1982; Lau & Ware, 1981). Implications for HLC conceptualization and measurement are discussed.     

Athletic self-concept and mathematics achievement in girls

Several researchers have suggested that girls' mathematics performance may be mediated by an assertive sex role or "masculine interest." The present study made the assumption that girls' athletic self-confidence reflects "masculine interest" so girls' test scores for perceived athletic competence would be related to their mathematics achievement scores. A total of 207 boys and girls in Grades 4, 5, and 6 were tested for their perceived athletic ability using the Athletic Competence subscale of Harter's 1985 Self-perception Profile, and these scores were correlated with their mathematics achievement as measured on the Metropolitan Achievement Test and term grades. A low but significant correlation with Athletic Competence scores was found for girls on both measures of mathematics achievement. Although boys scored higher on the Athletic Competence subscale, there were no sex differences on either measure of mathematics achievement. Results are discussed in terms of both sex-role theory and cognitive development.     

The analysis of one-way between effects in fluency research

In fluency research, the potential for extreme variance heterogeneity exists when comparing stutterers to other disordered or control populations. There is now a growing concern on the part of statisticians that the F statistic is not nearly so robust to violations of the homogeneity of variance assumption as was once thought. Together, these two circumstances represent potential for compromise on the statistical conclusion validity of fluency research. In this first of two papers, alternatives to the usual analysis of variance are described for the research design involving a single between effect. A second paper will be a similar treatment of the two-way between effects design.     

Performance objectives in the stance phase of human pathological walking

Permanent disruption of aspects of a highly learned skill such as walking force adaptations to occur to the movement. Firstly the body must determine what factors will guide the formation of the new walking pattern, and secondly that new movement pattern must be learned. Frequently the questionable assumption is made that the performance objectives of the new skill are the same as the original. This work used non-linear optimal control and multiple segment simulation to evaluate the ability of several possible objective functions to predict pathological walking patterns. These predictions were then also compared to the results from normal walking. Preliminary results indicate the performance objectives of pathological gaits may be quite different from those of normals. Some support was also provided for the existence of simultaneous multiple performance objectives in complex movements.