Effects of extensive dual-task practice on processing stages in simultaneous choice tasks

Schumacher et al. Psychological Science 12:101–108, (2001) demonstrated the elimination of most dual-task costs (“perfect time-sharing”) after extensive dual-task practice of a visual and an auditory task in combination. For the present research, we used a transfer methodology to examine this practice effect in more detail, asking what task-processing stages were sped up by this dual-task practice. Such research will be essential to specify mechanisms associated with the practice-related elimination of dual-task costs. In three experiments, we introduced postpractice transfer probes focusing on the perception, central response-selection, and final motor-response stages. The results indicated that the major change achieved by dual-task practice was a speed-up in the central response-selection stages of both tasks. Additionally, perceptual-stage shortening of the auditory task was found to contribute to the improvements in time-sharing. For a better understanding of such time-sharing, we discuss the contributions of the present findings in relation to models of practiced dual-task performance.     

An explanation of the hard-easy effect in studies of realism of confidence in one's general knowledge

Abstract

Recent ecological approaches to realism of confidence in general knowledge (Gigerenzer, Hoffrage & Kleinbolting, 1991; Juslin, in press) argue that people are well-calibrated to their natural environments. Both the overconfidence phenomenon and the hard-easy effect are explained as consequences of informal experimenter-guided selection of almanac items, selection that changes the validity of the cues used by the subjects for selection of answers to the items. The paper presents the ecological approach and reports an experiment showing that: (1) when the objects of judgement are selected randomly from a natural environment, people are well-calibrated; (2) when more and less difficult item samples are created by selecting items with more and less familiar contents, i.e. in a way that does not affect the validity of the cues, no hard-easy effect is observed, and people are well-calibrated both for hard and easy item samples. These results, predicted by the ecological approach, provide further support for the ecological approach to realism of confidence.     

Disturbances of consciousness in dementia with Lewy bodies associated with alteration in nicotinic receptor binding in the temporal cortex

Disturbances of consciousness, including fluctuations in attention and awareness, are a common and clinically important symptom in dementia with Lewy bodies (DLB). In the present study we investigate potential mechanisms of such disturbances of consciousness (DOC) in a clinicopathological study evaluating specific components of the cholinergic system. [3H]Epibatidine binding to the high-affinity nicotinic receptor in the temporal cortex (Brodmann's areas 20 and 36) differentiated DLB cases with and without DOC, being 62-66% higher in those with DOC (F=4.5,p=.025). The were no differences between DLB patients with or without DOC in 125I-labeled alpha-bungaratoxin binding to the low-affinity nicotinic receptor, [3H]pirenzepine binding to the muscarinic M1 receptor, or in choline acetyltransferase activity. These findings provide support for the hypothesis that cholinergic activity is an important neural correlate if consciousness and suggest a mechanism of DOC in DLB involving alterations in the nicotinic receptor, composed of predominantly alpha4 and beta2 subunits.     

Decision-making deficits in drug addiction

Core aspects of addictive behaviour can be explained in terms of abnormal decision-making. Using recording of autonomic function during performance of two gambling tasks, Bechara et al. have recently identified three distinct neuropsychological subtypes in individuals with substance dependence. These subtypes may reflect dissociable patterns of disruption in limbic brain circuitry.     

Investment in body image among patients diagnosed with or at risk for malignant melanoma

We examined investment in body image among 48 patients diagnosed with, or at risk for malignant melanoma (MM), as well as factors hypothesized as related to increased investment, such as gender, perceived stress, mood, fatigue, and personality characteristics. Investment in body image was evaluated using the Measure of Body Apperception [Carver, C. S., Pozo-Kaderman, C., Price, A. A., Noriega, V., Harris, S. D., Derhagopian, R. S., Robinson, D. S., & Moffat, F. L. Jr. (1998). Concern about aspects of body image and adjustment to early state breast cancer. Psychosomatic Medicine, 60, 168–174]. Results showed that women reported more concerns about physical appearance than men, and patients with MM exhibited more concerns about body integrity than at-risk patients. Concerns about body integrity were related to more compulsive personality characteristics, whereas concerns about appearance were associated with more histrionic personality characteristics. Body image investment was related to poorer adjustment as indicated by heightened symptoms of fatigue and stress. This study suggests that further research on investment in body image in this patient population is warranted.     

Matters temporal

Current evidence suggests that neural Hebbian learning in cortical and hippocampal synapses is fundamentally predictive rather than conventionally correlational. Much attention is focussing on what sort of predictions are acquired, and in what neural architectures. A recent paper by Rao and Sejnowski has suggested an interesting interpretation in terms of a popular predictive algorithm that has roots in psychology, computer science and engineering.     

Why Do Churches Become Empty,While New Age Grows? Secularization and Religious Change in the Netherlands

Research from the Netherlands has pointed out that the increased popularity of New Age since the 1960s by no means compensates for the dramatic decline of the Christian churches. From a theoretical point of view, however, it is more important to study why those remarkably divergent developments have occurred in the first place. This article does this by analyzing survey data collected among the Dutch population at large in 1998, focusing on a comparison of the young and the elderly. It is concluded, first, that there are no indications that the decline of the Christian tradition has been caused by a process of rationalization. Second, the decline of the Christian tradition and the growth of nonreligiosity as well as New Age are caused by increased levels of moral individualism (individualization). Implications for the sociological analysis of cultural and religious change are discussed.     

Playing Mating Games in Foreign Cultures: A Conceptual Framework and an Experimental Paradigm for Inductive Trivariate Inference

A conceptual framework is presented for studying trivariate inference, in which the influence of a primary independent factor, x, on a dependent variable, y, depends on a secondary factor, z. In two experiments, this was operationalized as the contingency between mating strategies, x, and mating success, y, for targets stemming from different tribes, z. In Experiment 1, z was manipulated to produce four contingency types: control, orthogonal, suppressor, and spurious correlations. Performance variation was not restricted by encoding capacity; explicit and implicit measures were more accurate at the trivariate level than at the bivariate level of assessment. Aside from normal regression effects, neither task complexity nor competition among influence factors led to impaired performance. Impairment was evident mainly in a radical discounting effect for spurious correlations due to representational conflicts. Experiment 2 demonstrates that the difficulties with spurious correlations can be overcome when temporal cues disambiguate the joint influence of x and z on y.