Category variability, exemplar similarity, and perceptual classification

Experiments were conducted in which observers learned to classify simple perceptual stimuli into low-variability and high-variability categories. Similarities between objects were measured in independent psychological-scaling tasks. The results showed that observers classified transfer stimuli into the high-variability categories with greater probability than was predicted by a baseline version of an exemplar-similarity model. Qualitative evidence for the role of category variability on perceptual classification, which could not be explained in terms of the baseline exemplar-similarity model, was obtained as well. Possible accounts of the effects of category variability are considered in the General Discussion section.     

How golden hamsters (Mesocricetus auratus) discriminate top from bottom flank scents in over-marks

Using a habituation-discrimination paradigm, the authors investigated what cues male golden hamsters (Mesocricetus auratus) use to determine the top and bottom positions in flank gland over-marks. A difference in the ages of 2 hamsters' marks did not, by itself, produce differential memory or evaluation of the 2 scents. A spatial configuration of marks suggestive of an overlap was sufficient for the apparently overlapping scent to be remembered or valued more than the apparently underlying scent. Cues from the overlap of 2 hamsters' marks were also sufficient. These results, consistent with those previously found for responses to hamster vaginal scent over-marks, suggest that hamsters use similar cues to analyze scent over-marks that are different in chemical composition and in social functions.     

Deductivism Within Pragma-Dialectics

The present paper elaborates a deductivist account of natural language argu-ment in the context of pragma-dialectics. It reviews earlier debates, criticizes some standard misconceptions in the literature, and argues that the identification and analysis of deductive argument schemes can be the basis of a compelling theory of argumentative discourse.     

Infants' Perception of Causal Chains

Three experiments examined infants' and adults' perception of causal sequences of events. In a causal-chain sequence, the first action causes a second action that then causes a final outcome; in a temporal-chain sequence, the first two actions are independent and the second action causes a final outcome. Infants and adults were shown the same event sequences; infants were tested using a visual habituation paradigm, whereas adults were given a questionnaire. Experiment 1 indicated that 15-month-old infants perceive the primary cause of the final outcome to be the first action in a causal chain but the second action in a temporal chain. Experiment 2 showed that adults interpret the causal sequences in a manner similar to that of 15-month-olds. Finally, Experiment 3 showed that 10-month-old infants do not yet perceive causal sequences in the same manner as 15-month-olds and adults. These results are interpreted in terms of both infants' developing knowledge of causal events and adults' attributions of causality in complex events.     

Applying Utilization Management Principles to a Comprehensive Service System for Children with Emotional and Behavioral Disorders and Their Families: A Feasibility Study

The Comprehensive Services Act for At Risk Youth and Families of Virginia (CSA), is a service, funding, and organizational reform initiative designed to improve the provision of child centered and family focused services within a community setting. We conducted this study in order to assess the feasibility of applying utilization management principles to the CSA in order to improve the appropriateness, quality, and cost effectiveness of this service delivery system. Data were gathered through focus groups, surveys, clinical profiling, and analysis of costs, and service utilization. While overall program costs increased since inception of the program, the costs per child served rose less than the rate of inflation. CSA appeared to be serving children with a high degree of emotional and behavioral difficulties. There was considerable variation among localities in placement patterns. A majority of survey and focus group respondents were willing to consider the application of utilization management principles to the CSA as long as decision making remained within localities. We concluded that there is a constructive role for utilization management approaches to improve the appropriateness and quality of services as well as enhancing efficiency in child mental health.     

Context-processing deficits in schizophrenia: converging evidence from three theoretically motivated cognitive tasks

To test the hypothesis that the ability to actively represent and maintain context information in a central function of working memory and that a disturbance in this function contributes to cognitive deficits in schizophrenia, the authors modified 3 tasks--the AX version of the Continuous Performance Test, Stroop, and a lexical disambiguation task--and administered them to patients with schizophrenia as well as to depressed and healthy controls. The results suggest an accentuation of deficits in patients with schizophrenia in context-sensitive conditions and cross-task correlations of performance in these conditions. However, the results do not definitively eliminate the possibility of a generalized deficit. The significance of these findings is discussed with regard to the specificity of deficits in schizophrenia and the hypothesis concerning the neural and cognitive mechanisms that underlie these deficits.     

Effects of weight cycling on metabolic control in male outpatients with non-insulin-dependent diabetes mellitus

Examined the effects of weight cycling (i.e., losing and regaining or gaining and relosing body weight) versus weight maintenance on metabolic control in 327 adult, male, outpatient veterans with non-insulin-dependent diabetes mellitus (NIDDM) who were followed over an average of 3.4 years. When compared with weight maintenance, weight cycling, whether defined as a categorical or as a continuous variable, was not found to be associated with deficits in metabolic control or increased need for hypoglycemic medication. Patients who weight cycled had fasting serum glucose and hemoglobin A1c levels comparable to those who remained within 10% of their initial body weights, and these levels of metabolic control were obtained with similar classes and dosages of hypoglycemic medication.