Incorporating prior theory in covariance structure analysis: A bayesian approach

A Bayesian approach to the testing of competing covariance structures is developed. The method provides approximate posterior probablities for each model under consideration without prior specification of individual parameter distributions. The method is based on ayesian updating using cross-validated pseudo-likelihoods. Given that the observed variables are the samefor all competing models, the approximate posterior probabilities may be obtained easily from the chi square values and other known constants, using only a hand calculator. The approach is illustrated using and example which illustrates how the prior probabilities can alter the results concerning which model specification is preferred.     

Right hemisphere contribution to lexical access in an aphasic with deep dyslexia

Three hemifield tachistoscopic studies of a right-handed patient with acquired Broca's aphasia and deep dyslexia, but with intact visual fields, are presented to support the hypothesis of right hemisphere (RH) participation in deep dyslexic reading. A systematic comparison of this deep dyslexic with the disconnected RHs of two patients with complete cerebral commissurotomy disclosed a similar, but not identical, pattern of abilities. The results demonstrate partial reliance on the RH for accessing the meaning of single words, but not for phonological encoding in this patient.     

A componential model for mental addition

A componential model capable of representing simple and complex forms of mental addition was proposed and then tested by using chronometric techniques. A sample of 23 undergraduate students responded to 800 addition problems in a true-false reaction time paradigm. The 800 problems comprised 200 problems of each of four types: two single-digit addends, one single- and one double-digit addend, two double-digit addends, and three single-digit addends. The results revealed that the columnwise product of addends, a structural variable consistent with a memory network retrieval process, was the best predictor of mental addition for each of the four types of problem. Importantly, the componential model allowed estimation of effects of several other structural variables, e.g., carrying to the next column and speed of encoding of digits. High levels of explained variance verified the power of the model to represent the reaction time data, and the stability of estimates across types of problem implied consistent component use by subjects. Implications for research on mental addition are discussed.     

Social and life skill competence in potential early school-leavers

Competencies in social and life skills of a group of students expecting to leave school at the end of Grade 10 in Australia is compared with groups expecting to continue. Academic performance and skills were also assessed. The results of the study indicated that the potential early school-leavers were disadvantaged both socio-economically and academically. But, surprisingly, the findings indicated that they were not significantly different from the other two groups of students targeted in the study in terms of their social and life skills. The results imply that potential early leavers in school populations may be unnecessarily disadvantaged because school programmes, in concentrating on a narrow range of cognitive skills, do not build on personal competency skills already possessed by students of all levels of ability. Whilst this is the case, potential early school-leavers will be likely to continue to be disaffected and disadvantaged educationally.     

Potential for hostility and dimensions of anger

Recent reviews have linked Potential for Hostility derived from the Structured Interview (SI) to coronary artery disease, independent of the global Type A pattern. The present study examined the construct validity of Potential for Hostility ratings by correlating Potential for Hostility with 21 scales from four widely used anger/hostility measures: 7 scales from the Anger Self-Report, 8 scales from the Buss-Durkee Hostility Inventory, the total score from the Novaco Anger Inventory, and 5 scales from the Multidimensional Anger Inventory. The pattern of correlations revealed that Potential for Hostility was significantly related to scales reflecting awareness and arousal of anger, particularly the verbal expression of anger. To identify underlying anger dimensions, the 21 scales were factor-analyzed. Examination of two and three rotated principal components confirmed previous solutions. The first component, representing anger-arousing and -eliciting situations and anger awareness, was labeled Experience of Anger. The second component, consisting of scales dealing with either physical assault or verbal expression of anger, was labeled Expression of Anger. When a third factor was retained, it contained scales of suspicion, mistrust-suspicion, and guilt: It was therefore labeled Suspicion-Guilt. Potential for Hostility was correlated only with the Expression of Anger factor in the two-factor solution; in the three-factor solution, Potential for Hostility was correlated equally with the Experience of Anger and Expression of Anger factors but was not correlated with the Suspicion-Guilt factor. The implications of these results for the assessment of hostility are discussed.     

Age differences in the acculturation process

Age differences were assessed in a conceptual model that seeks to explain how acculturation affects psychological well-being among Mexican Americans. The data were from a national probability sample of 859 persons of Mexican decent. It was hypothesized that low acculturation creates financial stress. Moreover, low acculturation and financial stress were in turn predicted to erode feelings of personal control and self-esteem. Finally, diminished feelings of control and low self-esteem were hypothesized to exert a negative impact on psychological well-being. When data from respondents of all ages was assessed, empirical support was found for all of the hypotheses except the linkage between acculturation and financial stress. However, few age differences emerged in the model. The authors conclude that older Mexican Americans may not be more vulnerable to the stressors associated with acculturation.     

Expert evidence by psychologists: Sometimes problematic and often premature

This article provides a critical review of two major types of expert evidence: (a) clinical assessments, and (b) generalizations drawn from psychological research. Strong arguments both for and against both types of testimony have been offered by legal experts and psychologists. These arguments are evaluated and the conclusion is drawn that there are two fundamental problems for psychologists in the role of expert. First, the types of assessments clinicians are asked to make (e.g., concerning the accused's mental state at the time of committing the offense) may exceed the capacity of the discipline; such assessments are problematic. Second, the research foundation that psychologists employ in court does not always apply to the court situation in the way experts imply; the application of laboratory research findings to real world contexts is sometimes premature. The article concludes with an admonition that psychologists should adopt a more conservative response to requests to provide expert evidence.