Testing the predictions of the central capacity sharing model

The divergent predictions of 2 models of dual-task performance are investigated. The central bottleneck and central capacity sharing models argue that a central stage of information processing is capacity limited, whereas stages before and after are capacity free. The models disagree about the nature of this central capacity limitation. The central bottleneck model claims that central processing acts on only 1 task at a time and, therefore, constitutes a bottleneck that processes tasks serially. The central capacity sharing model postulates that the central stage is a limited-capacity parallel processor that divides resources among to-be-performed tasks. As a result of this difference, in the psychological refractory period paradigm, the central capacity sharing model predicts that lengthening Task 2 precentral processing will improve Task 1 performance at short stimulus onset asynchronies, whereas the central bottleneck model does not. Results of 2 experiments confirm the prediction of the central capacity sharing model.     

Changes in the neuropsychological correlates of clinical dimensions between the acute and stable phase of schizophrenia

This study was designed to investigate whether the neuropsychological correlates of the symptom dimensions of schizophrenia vary with the clinical state in patients followed from the acute to stable the phase of the illness. Fifteen patients were assessed for symptoms (SAPS-SANS) and undergone a complete neuropsychological assessment at two sessions. The first session (S1) was carried out within six days after admission, i.e., acute phase and the second (S2) at least two month after hospitalization, i.e., stable phase. The data were analyzed using stepwise regression models in which neuropsychological scores were in entered to predict each dimensional score. This analysis was applied on the S1 and S2 data as well as on the S2-S1 difference to assess the neuropsychological predictors of clinical changes. Generally, the results replicate the previous associations between neuropsychological and dimensional measures found in stable patients. In addition, this study shows if each dimension appears to rely on a key structure, symptom variations seems to involve changes in the spread of the dysfunction and/or changes in the connectivity between the key and other regions. The results also suggest that functional changes related to some symptoms dimensions occur to compensate for the dysfunction associated with other symptoms.     

Development and validation of a brief version of the dyadic adjustment scale with a nonparametric item analysis model

The main purpose of the current research was to develop an abbreviated form of the Dyadic Adjustment Scale (DAS) with nonparametric item response theory. The authors conducted 5 studies, with a total participation of 8,256 married or cohabiting individuals. Results showed that the item characteristic curves behaved in a monotonically increasing function for all items of the brief 4-item version of the DAS (DAS-4). The DAS-4 proved to be informative at all levels of couple satisfaction. Compared with the 32-item version of the DAS (DAS-32), it was as effective in predicting couple dissolution and was significantly less contaminated by socially desirable responding. In addition, structural equation modeling demonstrated that the underlying latent construct measured by the DAS-4 was very stable over a 2-year period. This brief version has the advantage of being less time consuming and constitutes a promising alternative to the original DAS-32 for clinicians and researchers.     

Cytokine production by spleen cells after social defeat in mice: activation of T cells and reduced inhibition by glucocorticoids

Social disruption (SDR) is an effective model of social stress associated with an enhanced inflammatory reactivity of the immune system. The aim of the present study was to further describe SDR effects on cytokine production by spleen cells, testing selectively monocyte and T cell functions as a result of this stressor. For this purpose, splenocytes from control mice (C) and mice socially stressed for 7 days (SDR) were cultured in the presence of lipopolysaccharide (LPS) or concanavalin A (Con A). Splenocyte proliferation, cytokine production and sensitivity of spleen cells to corticosterone were assessed in vitro. The humoral response to keyhole limpet hemocyanin (KLH) immunization was assessed. SDR induced splenomegaly and enhanced splenocyte basal proliferation. The pro-inflammatory influence of SDR was confirmed by an increased release of interleukin-6 (IL-6) by LPS-stimulated cultures and by a reduced sensitivity of spleen cells to the anti-inflammatory effect of corticosterone. The mechanism increasing cytokine production in response to LPS was cytokine specific, since among inflammatory cytokines, IL-6 but not interferon-gamma (IFN-gamma) was enhanced by stress. In stressed mice, the increase in IL-6 and IFN-gamma and the decrease in IL-10 release in Con A-stimulated cultures indicate that SDR did not modify the Th1/Th2 cytokine balance but globally activated T cells. Plasma anti-KLH antibody levels were similar in both groups. Wounded and non-wounded mice presented similar responses to stress. This study shows that social disruption stress enhances the reactivity of cells from both the acquired and innate immune systems.     

A Critique of Miller and Rohling's Statistical Interpretive Method for Neuropsychological Test Data

A critical review of the 24-step procedure of Miller and Rohling's (in press) proposed standardization of clinician's use of neuropsychological assessment batteries is presented. Each step is examined for statistical sources of invalidity. It was concluded that parts of the procedure are quite vulnerable to between-battery variability that cannot be easily estimated or controlled, leading to significant errors in analysis and classification. A second fatal flaw is the failure to distinguish in the procedures between standard error measurement and standard error of the estimate in calculations in several steps. The purpose of the process remains viable, however, and is an important contribution toward the improvement of clinical diagnosis.     

Changing features do not guide attention in change detection: Evidence from a spatial cuing paradigm

Smilek, Eastwood, and Merikle (2000) demonstrated that the detection of change was facilitated when the target character changed in many rather than few of its features. Specifically, the function relating search response time to display set size was shallower when more features changed than when fewer features changed. The researchers interpreted these results as indicating that large feature changes provide preattentive guidance of focal attention to the location of the change. We tested this preattentive guidance hypothesis by examining change detection performance in the context of a spatial cuing paradigm. The hypothesis predicts that (1) the cost on invalidly cued trials should be less when more features change than when fewer features change, and (2) the features manipulation should have no effect on validly cued trials. In contrast to these predictions, our results show that cuing effects are equivalent across all levels of feature change and that a robust effect of the features manipulation is observable for both validly and invalidly cued trials. We argue that large feature changes do not provide preattentive guidance and in fact can be detected more readilyafter attention is already in place at the target location.     

Adolescent personality: a five-factor model construct validation

The purpose of this study was to investigate convergent and discriminant validity of the five-factor model of adolescent personality in a school setting using three different raters (methods): self-ratings, peer ratings, and teacher ratings. The authors investigated validity through a multitrait-multimethod matrix and a confirmatory factor analysis correlated trait, uncorrelated method model. With the exception of Emotional Stability, each analysis demonstrated similar patterns and together provided support for the convergent and discriminant validity of the five-factor model structure of adolescent personality. However, among the three raters, self-ratings of personality provided a comparatively weaker method for assessing adolescent personality. The influences of agreement between self and other raters are discussed in relation to contrast, perceiver, and target effects; expert observer effects; the degree of acquaintanceship; and the effect of the social context.     

A pilot study of an intervention for breast cancer survivors and their spouses

Recent studies have shown that interventions that increase breast cancer patients' communication with family members lead to reduced patient distress. In this article, we report on a treatment development and pilot study of an intervention for couples coping with breast cancer. In phase 1 of this study, 10 couples participated in two focus groups that generated ideas and themes for the intervention. In phase 2, we developed and pilot tested our intervention with 48 couples: 12 in a 2-session format, 21 in a 1-session format, and 15 in a non-experimental control group. Our response rate shows that breast cancer patients and spouses were willing to participate and that treatment providers were willing to refer patients and their spouses. The 2-session format showed the most promise for producing positive change in mental health functioning and cancer-related stress.     

Virtually no evidence for virtually perfect time-sharing

An examination of previous claims for virtually perfect time-sharing in dual-task situations reveals confounding effects that may have obscured dual-task interference. Two experiments are conducted in which these confounding effects are minimized, revealing statistically significant dual-task interference. These results support the hypothesis that human information processing is dominated by a structural central capacity limitation and call into question the hypothesis that dual-task interference can be eliminated by meeting the 5 conditions outlined by D. Meyer and D. Kieras (1999).     

Arguments for adjuncts

It is commonly assumed across the language sciences that some semantic participant information is lexically encoded in the representation of verbs and some is not. In this paper, we propose that semantic obligatoriness and verb class specificity are criteria which influence whether semantic information is lexically encoded. We present a comprehensive survey of the English verbal lexicon, a sentence continuation study, and an on-line sentence processing study which confirm that both factors play a role in the lexical encoding of participant information.