EFFECTS OF A VARIABLE-RATIO REINFORCEMENT SCHEDULE WITH CHANGING CRITERIA ON EXERCISE IN OBESE AND NONOBESE BOYS

The effects of a variable-ratio schedule of reinforcement on pedaling a stationary exercise bicycle were examined. Three obese and three nonobese 11-year-old boys were individually tested five times weekly for approximately 12 weeks. A changing-criterion design was used in which each successive criterion was increased over mean performance rate in the previous phase by approximately 15%. The contingencies of the successive criteria resulted in systematic increases in rate of exercise for all children. Final variable-ratio rates were higher than those under fixed ratios found in previous research, with rates for 2 of the 3 obese boys approximating those of the nonobese.     

Affective valence and memory in depression: dissociation of recall and fragment completion.

Depressed (n = 16) and nondepressed (n = 16) subjects' memory for affectively valenced words was assessed by an explicit test (free recall) and an implicit test (word fragment completion). Under free-recall instructions, depressed subjects recalled significantly more negatively valenced than positively valenced words, whereas the opposite pattern was observed in nondepressed control subjects. These results replicate those previously reported in the literature. The differential effect of word valence was absent, however, when memory was tested implicitly: Depressed and nondepressed subjects exhibited equivalent priming of positive and negative words. These data are discussed in terms of Williams, Watts, MacLeod, and Mathews's (1988) model of depression.     

Linking empirically based theory and evaluation: The family bereavement program

Conclusion We have illustrated how our small theory (Lipsey, 1990) of bereavement guided the development and evaluation of a preventive intervention for bereaved children. Our small theory, based on prior empirical research, enabled us to identify family processes that appeared to mediate the effects of parental death on child mental health. Our intervention was designed to attempt to change these processes. The evaluation of our experimental trial of the intervention assessed changes on these processes as well as the more distal mental health outcomes. The experimental trial showed some-what encouraging results, in terms of the program's ability to modify the warmth of the parent–child relationship and to decrease symptomatology in the adolescent children. We also obtained further empirical support for our underlying theoretical model. Finally, implications for redesign of the program were derived from assessing the adequacy of the program components to change each of the mediators in the theoretical model.Support for this research was provided by NIMH grant P5OMH39246 which is gratefully acknowledged. David R. Pillow is now at Western Psychiatric Institute, Pittsburgh; Fred Rogosch is at the University of Rochester; Janette Beals is now at University of Colorado Health Sciences Center; Kim D. Reynolds is now at the University of Alabama, Birmingham; Carl Kallgren is now at the Pennsylvania State University, at Erie; and Rafael Ramirez is now at the University of Puerto Rico.     

The application of Michel Foucault's philosophy in the problem externalizing discourse of Michael White

This paper examines how Michael White's theoretical and practice orientation can be mapped onto the work of French philosopher/historian Michel Foucault. Specifically, Foucault's analysis of his three modes of the objectification of the subject and the inseparability of power and knowledge will be viewed as similar to, and shaping of, White's conceptions of externalizing internalized problem discourse.
Where religions once demanded the sacrifice of bodies, knowledge now calls for experimentation on ourselves, calls us to the sacrifice of the subject of knowledge
Michel Foucault: Madness and Civilization     

The effects of social support on children's eyewitness testimony

Child witnesses often give only short accounts of witnessed events. Part of the reason for this failing centres on the stress present during an interview. The most obvious means of reducing stress in children, through the provision of social support, has typically been neglected in eyewitness research, presumably because of fears over children's excessive suggestibility. Social support is also believed to inhibit children during interviews. However, these fears appear to stem more from general suspicions about children's competencies rather than empirical findings. Studies are described which show that child witnesses express a strong desire for social support, and that support may be provided in a number of different ways, from peers as well as adults. It is argued that social support is one of the most unfairly neglected issues in eyewitness research, and the minimal evidence available suggests that allowing support may have a facilitative effect on task performance, including free-recall memory.     

A theory of cheating

The theory of motivated cheating postulates that test takers may cheat when they do not know an answer. With probabilityk, an “observer” is unsure of an answer and will copy from a nearby “target” with probabilityc. The corresponding parameters for the target may be entirely unrelated to those of the observer. Thus, the undesirable feature of bidirectionality of parameters found in correlational techniques is not an inherent feature of this theory of cheating. Predictions are derived, and estimates ofk andc are proposed. Statistically large values of c suggest that an observer was copying from a target. High values ofc for both the observer and the target suggest collusion. The theory is applied to a 40-item five-choice test taken by students in an introductory psychology section. From the full paired comparison matrix of target × observer parameter estimates, the method identifies 2 students who were probably in collusion.     

Psychological aspects of scuba diving injuries: Suggestions for short-term treatment from a psychodynamic perspective

Dive medicine is described as an area of practice in which psychologists may choose to expand their clinical service and research activities. The author argues that most research studying risk behavior and sports take into account biological, behavioral or cognitive approaches, while ignoring unconscious conflict in risk-taking and injury management. The present paper uses a psychodynamically-oriented, interview-based approach to studying psychological reactions to decompression sickness in three experienced scuba divers. Brief interventions and their outcomes are described.     

Incorporating the size principle into an ensemble of back-propagating neurons

As researchers try to move from cybernetics to neural reality, it is time to look at the match between the back propagation strategy and the functional parameters of neurons. Traditionally, the “bias value” in the back propagation activation function has served a mathematical rather than a biological function. By incorporating a production system into the activation logic at the hidden layer, we are able to arrive at a conditional bias value that approximates the function of thresholds in biological neurons.     

Experimental Personality Designs: Analyzing Categorical by Continuous Variable Interactions

Theories hypothesizing interactions between a categorical and one or more continuous variables are common in personality research. Traditionally, such hypotheses have been tested using nonoptimal adaptations of analysis of variance (ANOVA). This article describes an alternative multiple regression-based approach that has greater power and protects against spurious conclusions concerning the impact of individual predictors on the outcome in the presence of interactions. We discuss the structuring of the regression equation, the selection of a coding system for the categorical variable, and the importance of centering the continuous variable. We present in detail the interpretation of the effects of both individual predictors and their interactions as a function of the coding system selected for the categorical variable. We illustrate two- and three-dimensional graphical displays of the results and present methods for conducting post hoc tests following a significant interaction. The application of multiple regression techniques is illustrated through the analysis of two data sets. We show how multiple regression can produce all of the information provided by traditional but less optimal ANOVA procedures.     

Category typicality effects in episodic memory: Testing models of distinctiveness

Middle Tennessee State University, Murfreesboro, Tennessee Category typicality effects were investigated within the context of three models of distinctiveness: a univariate model, a fixed-multifeature model, and a weighted-multifeature model. High-typical, medium-typical, and atypical targets were embedded in lists containing a background set of mediumto high-typicality items. Atypical items were more poorly recalled than were medium- and high-typical items independently of list structure. In recognition, subjects who studied high-typical items had difficulty discriminating between high-typical items that were and were not presented as part of the list. However, item typicality had little effect on the recognition performance of subjects who did not study high-typical items. These findings were consistent with the weighted-multifeature model of distinctiveness.