Self-Efficacy,Perceptions of Success,and Intrinsic Motivation for Exercise1

A number of investigators have attempted to identify the determinants of continued participation in exercise regimens. Within a social cognitive framework, the present study examined the relationships among self-efficacy cognitions, perceptions of success, and multidimensional intrinsic motivation in the exercise domain. Multivariate analyses of variance indicated that highly efficacious individuals were more intrinsically motivated toward aerobic dance than were their less efficacious counterparts. However, multiple regression analyses revealed both perceptions of success and self-efficacy to account for significant variance in intrinsic motivation at both the composite and dimensional levels. Moreover, perceptions of success were considerably stronger predictors than were efficacy cognitions. The results are discussed in terms of the need for multiple measures of perceived success, the employment of longitudinal designs to determine the direction of causality among these variables, and possible implications for adherence issues.     

Co-operative solutions to the Prisoner's Dilemma

For helpful comments, my thanks to Robert Bright, Richmond Campbell, Julia Colterjohn, Peter Danielson, Ish Haji, Keith Lehrer, Robert Martin, Victoria McGeer, Terrence Tomkow and an anonymous referee. I also thank the Canadian S.S.H.R.C. for a Doctoral Fellowship and Dalhousie University for a Killam Post-Doctoral Fellowship.     

Violence and degradation as themes in "adult" videos

Videocassettes have become the dominant medium for pornography. One previous content analysis examined the prevalence of violence in such videos. The Attorney General's Commission on Pornography (1986) has asserted that nonviolent pornography depicting degradation produces harm similar to that from violent pornography. Content analysis of a 10% random sample (n = 50) of the videos displayed in the "adult" section of a video store showed that 13.6% of the scenes in the videos contained violent acts and 18.2% contained degrading acts.     

Categories and particulars: prototype effects in estimating spatial location

A model of category effects on reports from memory is presented. The model holds that stimuli are represented at 2 levels of detail: a fine-grain value and a category. When memory is inexact but people must report an exact value, they use estimation processes that combine the remembered stimulus value with category information. The proposed estimation processes include truncation at category boundaries and weighting with a central (prototypic) category value. These processes introduce bias in reporting even when memory is unbiased, but nevertheless may improve overall accuracy (by decreasing the variability of reports). Four experiments are presented in which people report the location of a dot in a circle. Subjects spontaneously impose horizontal and vertical boundaries that divide the circle into quadrants. They misplace dots toward a central (prototypic) location in each quadrant, as predicted by the model. The proposed model has broad implications; notably, it has the potential to explain biases of the sort described in psychophysics (contraction bias and the bias captured by Weber's law) as well as symmetries in similarity judgments, without positing distorted representations of physical scales.     

Attractors and perceptual field dynamics of homogeneous stimulus areas

Summary The phenomenon of the wandering point on a blank sheet of paper in serial reproductions is the starting point of an investigation of the perceptual field structure of homogeneous stimulus areas; 609 stimulus points distributed regularly in 21 rows and 29 columns on a DIN A4 sheet were presented successively to 10 subjects and had to be reproduced immediately afterwards in order to establish empirical vector fields. These were subjected to vector-analytic procedures. A method for the decomposition of the measured vector fields into partitions from gradient potentials and circulation potentials is demonstrated. The gradient potentials of the empirical vector fields revealed a highly regular structure with four point attractors near the corners of the sheet. A model calculation of the wandering point in this potential landscape showed results comparable to the empirical phenomenon. The results are discussed in favor of Gestalt theory and against direct perception.     

Analysis of the elements of attention: A neuropsychological approach

A model for conceptualizing the components or elements of attention is presented. The model substitutes for the diffuse and global concept of attention a group of four processes and links them to a putative system of cerebral structures. Data in support of the model are presented; they are derived from neuropsychological test scores obtained from two samples, the first consisting of 203 adult neuropsychiatric patients and normal control subjects, and the second, an epidemiologically-based sample of 435 elementary school children. Principal components analyses of test scores from these two populations yielded similar results: a set of independent elements of attention that are assayed by different tests. This work presents a heuristic for clinical research in which the measurement of attention is essential.     

Differential indication of trimipramine - results of a controlled multiclinical study]

The antidepressants trimipramine and imipramine were compared within the framework of a multiclinical study performed under the conditions of a controlled clinical experiment. There has been found a time-different remission of affective und psychomotoric symptoms. The panthymoleptic action of trimipramine and other antidepressants is discussed with reference to these results. Trimipramine influences psychotic states, especially if in depression anxiety is combined with agitation, also in hypochondriac forms of depression.     

The generality of learned helplessness in the rat

Two experiments were simultaneously conducted in which two different groups of 40 rats each were exposed to one of two different stressors. In both experiments half the subjects were pretreated with shock, half with underwater exposure. For each pretreatment stressor, half the subjects were allowed to escape, the other half were not. The experiments differed in the test task used. Approximately 24 hr after pretreatment, one-half the subjects from each pretreatment group received 20 water-escape trials in an underwater maze, the other half received 20 shock-escape trials in a two-way shuttle box. The subjects in each of the inescapable pretreatment conditions were slower to escape in the subsequent shock-escape and water-escape tasks when compared with subjects in the corresponding escapable pretreatment condition. The “learned helplessness” effect appeared to be no smaller when aversive stimuli were changed between pretreatment and test than when they remained the same.