Observations on the factor structure of the WAIS-R

Confirmatory factor analyses (CFAs) revealed 2 important characteristics of the standardization data of the Wechsler Adult Intelligence Scale Revised. One finding was that Digit Symbol fit better on an attentional factor in younger groups, but fit was better when Digit Symbol loaded on a visual-perceptual factor in older groups. A second observation was that specifying correlated errors or a fourth factor to explain covariance between Block Design and Object Assembly improved model fit in all age groups except 70- to 74-year-olds. The results illustrate the value of CFA and have implications for investigating other samples and other Wechsler tests.     

Exploring the effects of icon characteristics on user performance: the role of icon concreteness, complexity, and distinctiveness

Because icons, signs, and symbols are now widely used to communicate information, it is essential for system designers to know what makes them easy to use and interpret. The authors report a series of studies that examine characteristics considered central to icon usability. After quantifying the properties of icon concreteness, complexity, and discriminability, the authors assessed each property's effects on user performance when user experience, task demands, and presentation context were systematically varied. Findings indicated that the effects of icon concreteness were primarily associated with the initial grasp of meaning, whereas complexity effects were found to persist longer and to be associated with search efficacy. The effects of icon distinctiveness were complex, but distinctiveness was enhanced by using both semantic and visual contrasts. The implications of these findings for interface design are discussed.     

Theory-Driven Interventions in Psychoneuroimmunology and HIV-1 Infection

Psychoneuroimmunology (PNI) is a rapidly evolving multidisciplinary field founded on the premise that psychosocial factors, the central nervous system, and the immune system are intimately linked. Following publication of scientific evidence supporting this link, a number of animal and human studies have been published, both inside and outside the area of human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome. These studies support the existence of bidirectional feedback mechanisms operating between the brain and the immune system. To date, however, there is no all-encompassing model that predicts individual differences in the relationship among psychosocial factors, immunologic measures, and clinical disease progression in HIV type 1 (HIV-1) infection. This variability in human response has been explained by a number of cofactors (host as well as environmental) that appear to accelerate the course of the disease. Since psychosocial factors are highly amenable to behavioral interventions, several models for intervention research have been proposed to evaluate whether such interventions can enhance immune functioning, thereby curtailing disease progression. Examination of these interventions in the context of PNI and HIV-1 infection, however, is rather limited. Therefore, researchers and clinicians must not only consider conceptualizations and paradigms in this area of research, but also focus on empirically testable, theory-driven models that allow for the unique characteristics of individual patients.     

The name game: using retrieval practice to improve the learning of names

In medium-sized groups such as classes, it is often desirable that the members become acquainted with one another. Toward this end, various methods of introducing group members are often used, with only anecdotal evidence for their effectiveness. The name game is a method for introducing group members that is based on the principles of retrieval practice. The authors compared 2 versions of the name game with a widely used introductory method--pairwise introductions--and found that the name game participants were much better at remembering one another's name after 30 min, 2 weeks, and 11 months. A second experiment tested the contribution of retrieval practice by comparing 2 versions of the name game with a procedure that was matched for number of repetitions and time spent on the task. Again, the name games were superior.     

Adaptive automation, trust, and self-confidence in fault management of time-critical tasks

An experiment on adaptive automation is described. Reliability of automated fault diagnosis, mode of fault management (manual vs. automated), and fault dynamics affect variables including root mean square error, avoidance of accidents and false shutdowns, subjective trust in the system, and operator self-confidence. Results are discussed in relation to levels of automation, models of trust and self-confidence, and theories of human-machine function allocation. Trust in automation but not self-confidence was strongly affected by automation reliability. Operators controlled a continuous process with difficulty only while performing fault management but could prevent unnecessary shutdowns. Final authority for decisions and action must be allocated to automation in time-critical situations.     

Functional brain imaging as a looking-glass into the degraded brain: reviewing evidence from Alzheimer disease in relation to normal aging

Research on the real-time relationship between brain activity and mental performance is intense. However, relatively few studies have been devoted to patients with different diseases or lesions. Such studies may cast light on certain aspects of brain activity, such as plasticity. This review summarizes studies on Alzheimer's disease (AD) patients where the techniques to map brain activity in relation to mental performance have been utilized. Research findings suggest, that there is a spectrum of changes in AD patients that is distinct from that seen in healthy aging. These changes include: (i) loss of activated regions, (ii) reduced activation possibly due to brain degeneration typical of AD, (iii) the emergence of newly activated regions in order to compensate for minor brain deterioration (e.g., an enlargement of activated regions sometimes manifested as an increased bilaterality or a hemispheric shift of activation, and dedifferentiation), (iv) decreased level of activation, and (v) no change at all, which may occur in easy tasks or tasks that do not involve regions exposed to brain atrophy. In conclusion, the pattern of activation in AD depends on interactions between the clinical stage of patients, and the pattern of brain degeneration, as well as the task difficulty and specific networks necessary for solving the task.