The egocentric reference for visual exploration and orientation

Clinical signs of damage to the egocentric reference system range from the inability to detect stimuli in the real environment to a defect in recovering items from an internal representation. Despite clinical dissociations, current interpretations consider all symptoms as due to a single perturbation, differentially expressed according to the medium explored (perceptual or representational). We propose an alternative account based on the functional distinction between two separate egocentric mechanisms: one allowing construction of the immediate point of view, the other extracting a required perspective within a mental representation. Support to this claim comes from recent results in the domain of navigation, showing that separate cognitive mechanisms maintain the egocentric reference when actively exploring the visual space as opposed to moving according to an internal map. These mechanisms likely follow separate developmental pathways, seemingly depend on distinct neural pathways and are used independently by healthy adults, reflecting task demands and individual cognitive style. Implications for spatial cognition and social skills are discussed.     

Can residual lexical knowledge concern word form rather than word meaning?

We described a patient with a dramatic deficit of both word comprehension and naming but with good preservation of visual pictorial semantics. On word-picture matching, his performances were slightly better than expected based on the observed lexical semantic disorder; in addition, the patient, who maintained good preservation of his underlying phonology, showed a tendency to point to the picture phonologically related to the target. In order to interpret these data, we advanced the hypothesis that the patient, in spite of his virtually complete inability to name, would be able, in a word-picture matching task, to "covertly" (i.e., preverbally) retrieve the name from the picture and to use this name to attempt a match with the phonological form of the stimulus word. This mechanism, that we called "phonological" comprehension, would allow the identification of the correct target and would explain the choice of the phonologically related foil that was sometimes selected.     

Attributional processing style differences in depressed and nondepressed individuals

A series of four studies used different measures to assess the amount of attributional processing following failure and success. It was found that, from an actor's point of view, relatively depressed students consistently differed from relatively nondepressed students in the amount of their attributional processing. The depressed individuals reported more attributions for both hypothetical and real failure, compared to the nondepressed individuals. They also reported fewer attributions for hypothetical success than the nondepressed individuals. In line with previous findings, depressed individuals took less personal credit for their successes and ascribed their failures more pronouncedly to their lack of ability. The findings reflect a depressive attributional processing style that encompasses individual differences, both in the content and in the amount of causal thinking following failure and success. Integration of this style into the attributional helplessness model of depression is suggested. The findings are compatible with a differential self-esteem view of depression and with aspects of Kuhl's functional helplessness model of depression. Implications for depression therapy are briefly discussed.Financial support for the studies was obtained from the University of Bielefeld (Grants 0Z 2760/2774). I wish to thank Karola Bettmer, Thomas Feld, and Stefan Wächter for their participation in the collection and the preparation of the data, as well as Friedrich Försterling, Jonathan Harrow, Wulf-Uwe Meyer, and two unknown reviewers for their helpful comments on earlier versions of this paper.     

Temporal Perspectives of the Nanotechnological Challenge to Regulation: How Human Rights Can Contribute to the Present and Future of Nanotechnologies

Expectations play a central role in understanding scientific and technological changes. Future-oriented representations are also central with regard to nanotechnologies as they can guide policy activities, provide structures and legitimation, attract different interests, focus policy-makers’ attention and foster investments for research. However, the emphasis on future scenarios tends to underrate the complexity of the challenges of the present market of nanotechnologies by flattening them under the needs and promises of scientific research. This is particularly apparent if we consider the viewpoint of the regulator who faces two different ranges of problems with regard to the market and research and is expected, simultaneously, to manage two different types of regulatory instruments, pursuing at the same time the same goals. Instead, by favoring only the future scenarios, the regulator runs the risk of abruptly shifting from more flexible and elastic tools to forms of hard legislation, wasting, thus, the resources of the soft-regulation, in particular those of self-regulation. By referring primarily to the European context, human rights, also thanks to their normative structure of principles, can help in strengthening both the legislation needed for regulating the present market and the soft instruments needed for steering research and for fostering the stakeholders’ participation without sacrificing the coherence of the regulatory response.     

Many-Valued Points And Equality

In 1999, da Silva, D'Ottaviano and Sette proposed a general definition for the term translation between logics and presented an initial segment of its theory. Logics are characterized, in the most general sense, as sets with consequence relations and translations between logics as consequence-relation preserving maps. In a previous paper the authors introduced the concept of conservative translation between logics and studied some general properties of the co-complete category constituted by logics and conservative translations between them. In this paper we present some conservative translations involving classical logic, Lukasiewicz three-valued system L ₃, the intuitionistic system I ¹ and several paraconsistent logics, as for instance Sette's system P ¹, the D'Ottaviano and da Costa system J ₃ and da Costa's systems C _n, 1 n.     

The glare effect does not give rise to a longer-lasting afterimage

The glare effect is an illusion in which a region appears self-luminous when flanked by gradients that decrease in luminance with distance from the region (Zavagno, 1999 Perception 28 835-838). This region also appears brighter than a surface of the same luminance. We investigated, using the paradigm of afterimages, whether a low-level mechanism at the level of the retina or LGN could account for this apparent brighter sensation. We first replicated the result from the literature that brighter and longer-lasting physical stimuli generate longer-lasting afterimages. We then compared the glare-effect stimuli with their counterpart controls, and found that the glare-effect stimuli did not give rise to longer-lasting afterimages. This suggests that the apparent brighter sensation of the glare effect is not due to a retinal or LGN mechanism, but must have a cortical origin.     

Glowing greys and surface-white: the photo-geometric factors of luminosity perception

The perception of luminosity is thought to depend upon the intensity of the stimulus: a surface begins to appear self-luminous when it emits or reflects a certain amount of light. This is known as the luminosity threshold. It is a common opinion among vision scientists that such a threshold is correlated to the intensity of a perceptually white surface, in the sense that only an area of the visual field with luminance higher than perceived surface-white will appear luminous. Here we show grey colours that appear luminous in virtue of surrounding luminance ramps. These ramps are intended to mimic halos seen around light sources in natural environments. The results of three experiments indicate that the phenomenon is in direct contradiction to the aforementioned assumptions and suggest the existence of separate perceptual pathways for self-luminosity perception and for surface-colour perception.     

Respiration and postural sway: detection of phase synchronizations and interactions

The aim of the central nervous system in upright stance is to control an intrinsically unstable plant. Internal disturbances, such as haemodynamics and respiration, constitute an endogenous threat to equilibrium. The way CNS reacts to those perturbations was studied in this work, through the analysis of summary scores taken from posturographic and pneumographic data. Signals were recorded simultaneously during trials administered on a sample population of healthy young adults, while sitting and standing and at paced and spontaneous uncontrolled breathing. The extraction of posturographic and pneumographic parameters was accompanied by the utilization of techniques for the detection of phase synchronization in bivariate data, and the extraction of an interaction index, the mutual information MI. The effects of the biomechanical condition and respiratory amplitude on MI and summary measures were tested with a two-way ANOVA. Summary scores clearly depend on posture condition. Synchronization between breath and postural sway is always present, depends on both biomechanical condition and respiratory threat, and cannot be reduced to a simple linear relation.