Methods for evaluating empirical bayes point estimates of latent trait scores

Empirical Bayes point estimates of latent trait scores, derived under the assumptions of one of several test theory models, display a certain degree of instability unless the sample size is sufficiently large. A measure of this instability over repeated sampling is the distribution of the overall expected squared error loss which converges, both in probability and in the mean, to the minimum (Bayes) overall expected loss as sample size increases. An asymptotic distribution theory is developed, and the resulting large sample approximation is compared with results obtained from simulated data. Attention is also given to the effects of using a smoothing procedure.     

Structure in semantic memory: A probabilistic approach using a continuous response task

In the continuous response (CR) task, the subject is given the name of a familiar category and must respond with category examples within a fixed time limit. The response sequence and the interresponse times are the measured variables. A general model is proposed for performance in the CR task. The time taken to generate a response is identified with the shortest search time from among a set of simultaneous search processes. Each response has a generation probability that is a function of the parameters governing the search process durations. Data involving the category states in the United States are used to test the model. The model accounts for the performance of nearly all individuals in these data.This article is based on a dissertation completed at the University of California-Berkeley in partial fullfillment of the requirements for the Ph.D. degree in psychology. Portions of the article were presented at the joint meeting of the Psychometric and Classification Societies (June 1984) and at the meeting of the Society for Mathematical Psychology (August 1984). The authors wish to thank Barbara Mellers, Juliet Schaffer, Steve Palmer, and Eleanor Rosch for helpful comments.     

Presentation modality and proactive interference in short-term retention using a mixed-morality distractor task

Two experiments investigated the release from PI following a shift in mode of presentation of the study words. In each experiment, the interpolated task required processing of both auditory (A) and visual (V) information. The results were the same with mixed lists (Experiment I) and with independent groups (Experiment II): A release from PI was obtained following an A to V shift but not following a V to A shift. It was concluded that the mixed-modality filler task has functional characteristics very similar to those of an A filler and that the filler task influences the memory code for study items.     

Religious Affiliation Influences on the Health Status and Behaviours of Students Attending Seventh-Day Adventist Schools in Australia

Students attending Seventh-day Adventist (Adventist) schools in Australia have been shown to have better health status and behaviours compared to secular norms, yet these schools cater for a high percentage of non-Adventist students. The purpose of this study was to investigate the influence of religious affiliation (Adventist/non-Adventist) on the health status and behaviours of students attending Adventist secondary schools in Australia. The sample included 1734 students who responded to a health and lifestyle survey that captured demographic details, self-reported height and weight, self-reported health status, mental health and select health behaviours. Students who identified themselves as Adventist reported significantly better health behaviours than the non-Adventist students in several behavioural domains, especially among the male students. However, this did not translate to a difference in health status. Further research is needed to understand the causal mechanisms responsible for the potential health advantage of Adventist students, which may include family or church religious influences.     

American Indian methamphetamine and other drug use in the Southwestern United States

To investigate the extent of methamphetamine and other drug use among American Indians (AIs) in the Four Corners region, we developed collaborations with Southwestern tribal entities and treatment programs in and around New Mexico. We held nine focus groups, mostly with Southwestern AI participants (N = 81) from three diverse New Mexico communities to understand community members, treatment providers, and clients/relatives views on methamphetamine. We conducted a telephone survey of staff (N = 100) from agencies across New Mexico to assess perceptions of methamphetamine use among people working with AI populations. We collected and analyzed self-reported drug use data from 300 AI clients/relatives who completed the Addiction Severity Index (ASI) in the context of treatment at three diverse addiction treatment programs. Each focus group offered a unique perspective about the effect of drugs and alcohol on each respective community. Though data from the phone surveys and ASIs suggested concerning rates of methamphetamine use, with women more adversely affected by substance use in general, alcohol was identified as the biggest substance use problem for AI populations in the Southwest. There appears to be agreement that methamphetamine use is a significant problem in these communities, but that alcohol is much more prevalent and problematic. There was less agreement about what should be done to prevent and treat methamphetamine use. Future research should attend to regional and tribal differences due to variability in drug use patterns, and should focus on identifying and improving dissemination of effective substance use interventions.