The perception of an optical flow projected on the ground surface

In most experiments in which the importance of visual control on postural stability is studied, optical stimuli attached to vertical surfaces are used. Analyses of long-term standing readjustments generally involve back-and-forth movements of a visual scene or its projection on vertical circular screens. In a natural environment, however, visual information is largely available from the ground. The aim of the experiment reported was to assess the effect of a flow pattern simulating an open outdoor setting on motion perception and postural control. Subjects were presented with an optical texture projected onto the ground. Periods of motionless texture alternated with equivalent durations of unidirectional flows. The change of position of the subject's centre of gravity over time was recorded on a force platform. Results show that the direction of body sway corresponded with that of texture motion. Important aftereffects, as shown in linear vection experiments, were also observed. However, the latency of postural responses was much shorter than with prolonged unidirectional flows produced in other locations of the visual environment. The hypothesis of an ecological specificity of the flows perceived on the ground during terrestrial displacements is discussed.     

Interactions between area and numerosity

Summary The concept of filled area, i.e. the impressionistic ensemble of parts of a stimulus field occupied by dots, is used to account for various kinds of numerosity illusions due to perceptual interaction between a number of dots and their spatial arrangement. A measure of filled area is derived from a model for the perceptual clustering of dots on the basis of relative proximity. It is shown that the quantified concept of filled area successfully predicts illusion data from earlier studies. Subsequently, a two-alternatives forced-choice numerosity experiment is reported, the data of which gave further evidence of the predictive power of the filled-area hypothesis. Our approach is discussed with respect to spatial features of dot stimuli that might be in rivalry with the filled-area factor in numerosity-estimation tasks.     

The use of prediction data in understanding delinquency

Predicting delinquency is valuable for understanding the course of crime, factors that influence its course, and the identification of markers that signal deviant processes. In addition, prediction data are relevant for judicial and clinical decision making. This article summarizes research findings on the prediction of delinquency. In the realm of early childhood behaviors, there is consensus that aggression (especially in conjunction with hyperactivity), drug use, truancy, lying, stealing, general problem behaviors, and poor educational achievement all predict later delinquency, albeit to varying degrees, with composite prediction scales yielding the highest degree of accuracy. In addition, studies show a reasonable consensus that the following family factors also predict delinquency: poor supervision, lack of involvement by parents, poor discipline, rejection by a parent, parental criminality and aggressiveness, marital problems, parental absence, and poor parental health. Variables reflecting socialization processes predicted later delinquency as well as children's early behavior. Although studied less frequently, youngsters' association with deviant peers is also predictive of delinquency.     

The correlation between coping with stress and blood pressure reaction]

This study explored the relationship between individual strategies of coping and blood pressure responses during and after mental stress. Blood pressure behavior was measured noninvasively and continuously before, during and after a mental stress situation in 27 normotensive subjects. Coping strategies were assessed with the Stressverarbeitungsfragebogen (SVF; coping with stress inventory). Two extreme groups were formed on the basis of the scores in the SVF. Results were: (a) Individuals who used coping strategies characterized by controlling the situation directly and constructively, in contrast to probands not using these strategies, exhibited lower blood pressure during the stress situation and a faster return to baseline levels after cessation of stress. (b) Subjects using a coping behavior characterized by the use of defense mechanisms such as suppression and denial, also showed lower blood pressure during stress but a significantly delayed return to baseline levels of blood pressure after stress was concluded.     

Radikaler Konstruktivismus und Konstruktionismus

Both radical constructivism and constructionism are naturalized approaches to epistemology. They try to fertilize results from biology and psychology for epistemological aims. They both refuse epistemological realism as unsustainable metaphysics. This raises the problem of the range of the naturalistic approach to epistemology. Constructivism, in both forms, turns out to be untenable because it runs in an aporia: it must borrow from realism either, or it must qualify its own position as a metaphysical one. But therewith, constructivism would be blamed to be metaphysical itself.