A model of perceptual classification in children and adults

The developmental trend from overall-similarity to dimensional-identity classifications is explained by a quantitative model. I begin with the assumption that objects are represented in terms of constituent dimensions and that the representation of objects changes little with development. Given this assumption, the model has three major parts. First, the similarity between objects is a function of the combination of the constituent dimensional differences. I propose developmental change in the likelihood that dimensions are differentially weighted in the calculation of similarity. Second, the perceived similarities between objects are valued for the purpose of constructing classifications. I propose that similarities are valued more dichotomously with age, such that identity becomes increasingly special. Third, the valued similarities are used to choose the best classification of those possible. The model provides good qualitative fits to the extant data. Three experiments examining classifications in 2- to 8-year-olds and in adults support specific new claims of the model. The data and the model provide new insights about development, classification, and similarity.     

Mental health expert witnesses: Of science and crystal balls

This article reviews the history of and basis for mental health testimony. It surveys the roles of such experts in the legal system and the concomitant problems with current approaches. Finally, it suggests specific reforms that may improve the use of mental health experts in legal proceedings.     

The 20 questions task with families of schizophrenics: divergent findings

The study attempted to replicate and extend the results of an earlier study by Wild and Shapiro (16), establishing the utility of Mosher and Hornsby's (8) 20 Questions Task as a means of differentiating families with schizophrenic patients from those of psychiatrically hospitalized but nonschizophrenic individuals. In the current study, Wild and Shapiro's original design was expanded and revised by (a) diagnosing patients using Research Diagnostic Criteria rather than hospital diagnoses and (b) including families with schizophrenic daughters and/or one-parent families, in addition to intact families with schizophrenic sons. Families were comparable on age, intelligence, and socioeconomic variables. The results failed to replicate those reported by Wild and Shapiro, and indicated that the 20 Questions Task was sensitive to differences in family constellation and offspring gender as well as offspring diagnosis. The findings suggest that forms of familial communication deviance detected with the 20 Questions Task may not be unique to families of schizophrenics, thus highlighting the need to expand research on family communication deviance in families with schizophrenic offspring to families with varied family constellations and characteristics.     

Cardiovascular reactivity and interpersonal influence: active coping in a social context

Previous studies have demonstrated that effortful attempts to secure positive outcomes or avoid negative outcomes produce significant increases in systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR). Although these effects of active coping on cardiovascular reactivity are central in current psychosomatic theories, virtually all of the research to date has used impersonal, asocial tasks. Our two studies examined the cardiovascular effects of effortful attempts to influence other people. In Study 1, male subjects attempting to influence the opinions of their discussion partner to improve their own chances of winning money displayed significantly greater SBP, DBP, and HR reactivity. In Study 2, we obtained similar effects on SBP and DBP reactivity in men and women, while both preparing an influence attempt and making that attempt. Furthermore, reactivity levels were larger as the magnitude of incentive for successful persuasion increased. Implications of this interpersonal equivalent of active coping for the development of cardiovascular disease are discussed.     

Eyewitness accuracy and confidence: within- versus between-subjects correlations

Previous researchers using between-subjects comparisons have found eyewitness confidence and accuracy to be only negligibly correlated. In this study, we examined the predictive power of confidence in within-subject terms. Ninety-six subjects answered, and made confidence ratings for, a series of questions about a crime they witnessed. The average between-subjects and within-subject accuracy-confidence correlations were comparably low: r = .14 (p less than .001) and r = .17 (p less than .001), respectively. Confidence is neither a useful predictor of the accuracy of a particular witness nor of the accuracy of particular statements made by the same witness. Another possible predictor of accuracy, response latency, correlated only negligibly with accuracy (r = -.09 within subjects), but more strongly with confidence (r = -.27 within subjects). This pattern was obtained for both between-subjects and within-subject comparisons. The theoretical and practical implications of these results are discussed.     

The inequivalence of self-reports of Type A behavior: Differential relationships of the Jenkins Activity Survey and the Framingham cale with affect,stress, and control

The Jenkins Activity Survey (JAS) and the Framingham Type A Scale (FTAS) have been found to have different psychological correlates. The JAS is typically unrelated to anxiety, while the FTAS is consistently correlated with trait anxiety. The present study of 200 male and female college students clarifies further the psychological heterogeneity of these measures. Enhanced motivation to control the environment has been suggested as an underlying psychological component of Type A behavior (Glass, 1977). Dysphoric emotions and the perception of more environmental stresses, on the other hand, are typical of neuroticism or negative affectivity (Watson & Clark, 1984). Although the results indicate that the JAS and FTAS are highly correlated, the JAS is more closely related to control motivation than is the FTAS. Further, compared to the JAS, the FTAS is more closely correlated with dysphoric emotions and perceived daily stresses. Thus, the results indicate that the JAS is closely correlated with core psychological components of the Type A pattern, while the FTAS has a relatively unique association with general emotional distress. Such differences may account for the fact that these measures are related to different disease end points.     

Reflex responses of human lip muscles to mechanical stimulation during speech

The role played by reflex pathways in the production of movement has been a significant issue for motor control theorists interested in a wide variety of motor behaviors. From studies of locomotion and chewing, it appears that gains in reflex pathways can be altered so that activity in these pathways does not produce destabilizing responses during movement. In speech production, recent experimental evidence has been interpreted to suggest that autogenetic lip reflexes (perioral reflexes) are suppressed during sustained phonation or speech production. The present study was conducted to assess the effects of phonation, direction of movement, and ongoing speech production on reflex responses of lip muscles. The present results suggest, in contrast to earlier work, that this reflex pathway is not suppressed or absent because the amplitude of the observed response depends upon the activation levels of the various muscles of the lower lip and, therefore, indirectly on the nature of the gesture the subject is instructed to produce.     

Cognitive impairment in preschoolers: Identification using the personality inventory for children-revised

This study evaluated the clinical validity of the Intellectual Screening, Development, and Achievement scales of the Personality Inventory for Children-Revised (PIC-R), as well as the newly derived PIC-R Factor IV scale, in identifying cognitive impairment in a clinic-referred sample of preschoolers. The clinical validity of these PIC-R subscales was also compared to that of the Minnesota Child Development Inventory (MCDI). The results showed that the PIC-R scales and Factor IV were reasonably successful in identifying cognitively impaired preschoolers, but much less successful in identifying cognitively normal preschoolers. Overall, the MCDI was the most successful in correctly identifying the preschoolers' cognitive status.