High impact running improves learning

Regular physical exercise improves cognitive functions and lowers the risk for age-related cognitive decline. Since little is known about the nature and the timing of the underlying mechanisms, we probed whether exercise also has immediate beneficial effects on cognition. Learning performance was assessed directly after high impact anaerobic sprints, low impact aerobic running, or a period of rest in 27 healthy subjects in a randomized cross-over design. Dependent variables comprised learning speed as well as immediate (1 week) and long-term (>8 months) overall success in acquiring a novel vocabulary. Peripheral levels of brain-derived neurotrophic factor (BDNF) and catecholamines (dopamine, epinephrine, norepinephrine) were assessed prior to and after the interventions as well as after learning. We found that vocabulary learning was 20 percent faster after intense physical exercise as compared to the other two conditions. This condition also elicited the strongest increases in BDNF and catecholamine levels. More sustained BDNF levels during learning after intense exercise were related to better short-term learning success, whereas absolute dopamine and epinephrine levels were related to better intermediate (dopamine) and long-term (epinephrine) retentions of the novel vocabulary. Thus, BDNF and two of the catecholamines seem to be mediators by which physical exercise improves learning.     

Immersiveness and physiological arousal within panoramic video-based virtual reality.

In this paper, we discuss findings from a study that used panoramic video-based virtual environments (PVVEs) to induce self-reported anger. The study assessed "immersiveness" and physiological correlates of anger arousal (i.e., heart rate, blood pressure, galvanic skin response [GSR], respiration, and skin temperature). Results indicate that over time, panoramic video-based virtual scenarios can be, at the very least, physiologically arousing. Further, it can be affirmed from the results that hypnotizability, as defined by the applied measures, interacts with group on physiological arousal measures. Hence, physiological arousal appeared to be moderated by participant hypnotizability and absorption levels.     

Supervisors safety response: a multisample confirmatory factor analysis

Supervisors Safety Response (SSR) has been closely linked to workplace safety, and, as perceived by workers, it is considered to be one of the most influential issues with regard to employees compliance with safety behaviours. This study defines and tests a bifactorial and a monofactorial model of the SSR. Two facets of the SSR were measured: (a) supervisors response toward workers safe or unsafe behaviour and (b) supervisors safety attitudes and behaviours applied to their own work. In three samples of injured blue-collar workers ( N(1) = 110, N(2) = 123, N(3) = 104), multisample confirmatory factor analyses, using maximum likelihood estimation, were conducted to test both the bifactorial and the monofactorial model. Both models provide an overall good fit, but parsimony and the high correlation between factors in the bifactorial model support the monofactorial model. Attention is drawn to the measurement of the SSR as a diagnostic tool useful in selecting intervention goals, specifically integrating supervisors safety behaviour.     

What determines the speed of lexical access: homophone or specific-word frequency? A reply to Jescheniak et al. (2003)

A. Caramazza, A. Costa, M. Miozzo, and Y. Bi (2001) reported a series of experiments showing that naming latencies for homophones are determined by specific-word frequency (e.g., frequency of nun) and not homophone frequency (frequency of nun + none). J. D. Jescheniak, A. S. Meyer, and W. J. M. Levelt (2003) have challenged these studies on a variety of grounds. Here we argue that these criticisms are not well founded and try to clarify the theoretical issues that can be meaningfully addressed by considering the effects of frequency on homophone production. We conclude that the evidence from homophone production cannot be considered to provide support to 2-layer theories of the lexical system.     

Does Hiv or Poverty Cause Aids? Biomedical and Epidemiological Perspectives

This paper contrasts biomedical and epidemiological approaches to the diagnosis and treatment of disease, and uses Collingwood's "principle of the relativity of causes" to show how different approaches focus on different causal factors reflecting different interests. By distinguishing between the etiology of a disease and an epidemic, the paper argues that, from an epidemiological perspective, poverty is an important causal factor in the African AIDS epidemic and that emphasizing this should not be considered incompatible with recognizing the causal necessity of HIV for the AIDS disease.     

Infants' perception of depth from cast shadows

Five- and 7-month-old infants viewed displays in which cast shadows provided information that two objects were at different distances. The 7-month-olds reached preferentially for the apparently nearer object under monocular-viewing conditions but exhibited no reaching preference under binocular-viewing conditions. These results indicate that 7-month-old infants perceive depth on the basis of cast shadows. The 5-month-olds did not reach preferentially for the apparently nearer object and, therefore, exhibited no evidence of sensitivity to cast shadows as depth information. In a second experiment, 5-month-olds reached preferentially for the nearer of two objects that were similar to those used in the first experiment but were positioned at different distances from the infant. This result indicated that 5-month-olds have the motor skills and motivation necessary to exhibit a reaching preference under the conditions of this study. The results are consistent with the hypothesis that depth perception based on cast shadows first appears between 5 and 7 months of age.     

Self-representation: searching for a neural signature of self-consciousness

Human self-consciousness operates at different levels of complexity and at least comprises five different levels of representational processes. These five levels are nonconceptual representation, conceptual representation, sentential representation, meta-representation, and iterative meta-representation. These different levels of representation can be operationalized by taking a first-person-perspective that is involved in representational processes on different levels of complexity. We refer to experiments that operationalize a first-person-perspective on the level of conceptual and meta-representational self-consciousness. Interestingly, these experiments show converging evidence for a recruitment of medial cortical and parietal regions during taking a first-person-perspective, even when operating on different degrees of complexity. These data lend support for the speculative hypothesis, that there exist a neural signature for human self-consciousness that is recruited independent from the degree of representational complexity to be performed.