Reference frames and haptic perception of orientation: Body and head tilt effects on the oblique effect

The aim of this study was to examine the effect of body and head tilts on the haptic oblique effect. This effect reflects the more accurate processing of vertical and horizontal orientations, relative to oblique orientations. Body or head tilts lead to a mismatch between egocentric and gravitational axes and indicate whether the haptic oblique effect is defined in an egocentric or a gravitational reference frame. The ability to reproduce principal (vertical and horizontal) and oblique orientations was studied in upright and tilted postures. Moreover, by controlling the deviation of the haptic subjective vertical provoked by postural tilt, the possible role of a subjective gravitational reference frame was tested. Results showed that the haptic reproduction of orientations was strongly affected by both the position of the body (Experiment 1) and the position of the head (Experiment 2). In particular, the classical haptic oblique effect observed in the upright posture disappeared in tilted conditions, mainly because of a decrease in the accuracy of the vertical and horizontal settings. The subjective vertical appeared to be the orientation reproduced the most accurately. These results suggest that the haptic oblique effect is not purely gravitationally or egocentrically defined but, rather, depends on a subjective gravitational reference frame that is tilted in a direction opposite to that of the head in tilted postures (Experiment 3).     

Kooperatives Lernen auf der Grundlage komplementären Vorwissens: ein Experiment und eine Simulationsstudie

Summary. Knowledge acquisition in collaborative problem solving is mainly realized by two activities: (1) when participants mutually impart their knowledge and (2) when they elaborate their knowledge together. Both activities are favoured by differences in the participants' prior knowledge. To support this thesis, an experimental study and a cognitive simulation are described. In the study, pairs of students were systematically taught complementary knowledge about qualitative resp. quantitative aspects of classical mechanics. During the subsequent collaborative problem solving the students successfully exchanged information about their complementary knowledge. Students who had been taught knowledge about qualitative aspects of physics gained more from their partners than students who had been taught knowledge about quantitative aspects. A cognitive model simulates problem solving and learning under the conditions set up in the study. In a simulation study based on the cognitive model it was possible to reconstruct the main results of the experimental study. Finally, the role of dialogue analysis and external representations are discussed and conclusions for the design of computer systems supporting collaborative problem solving are drawn. Zusammenfassung. Wissenserwerb bei der Kooperation vollzieht sich vor allem durch zwei Aktivitäten: (1) gegenseitige Wissensvermittlung und (2) gemeinsame Elaboration des Wissens. Für beides ist unterschiedliches Vorwissen der Beteiligten eine günstige Voraussetzung. Um diese These zu unterstützen, wird im vorliegenden Artikel eine experimentelle Studie dargestellt, in der Paaren von Schülerinnen systematisch komplementäres Vorwissen über qualitative bzw. quantitative Aspekte der klassischen Mechanik vermittelt wurde. Beim anschließenden kooperativen Problemlösen vermittelten die Schülerinnen sich gegenseitig erfolgreich Teile ihres Wissens. Schülerinnen, die zuvor Wissen über qualitative Aspekte der Physik erworben hatten, lernten dabei mehr von ihren Partnerinnen als Schülerinnen, die zuvor Wissen über quantitative Aspekte erworben hatten. Ein nachfolgend implementiertes kognitives Modell simuliert kooperatives Lernen und Problemlösen unter den Bedingungen der Studie und ist in der Lage, die zentralen Befunde der Studie zu rekonstruieren. In der Diskussion wird auf die Rolle des Dialogverhaltens und der Nutzung externer Repräsentationen für das kooperative Lernen und Problemlösen eingegangen. Abschließend werden Schlußfolgerungen für die Gestaltung von Computersystemen zur Unterstützung kooperativen Lernens und Problemlösens gezogen.     

Valuing Happiness is Not a Good Way of Pursuing Happiness,but Prioritizing Positivity is: A Replication Study

Numerous studies confirm the merits of positive psychology. However, an emerging literature brings nuances, with one particular question concerning the impact of pursuing happiness: is this always positive? Some data suggest that an excessive level of valuing happiness may partly diminish the happiness felt, but that prioritizing positivity may increase subjective well-being. The aim of the present study was to replicate these findings. Participants (N = 683, 75% female) completed the prioritizing positivity scale (PPS) and the valuing happiness scale (VHS), as well as four well-being scales: the subjective happiness scale (SHS), the satisfaction with life scale (SWLS), the psychological well-being scales (PWB) and the center for epidemiological studies – depression (CES-D). Regression analyses showed that prioritizing positivity was positively associated with subjective happiness, life satisfaction and psychological well-being, but that it was negatively linked to depression. Opposite results partly emerged for valuing happiness. This cross-sectional study confirms that the way people pursue happiness, by prioritizing positivity or valuing it, may promote or partly hinder well-being.     

Special Issue: Character Strengths,Well-Being,and Health in Educational and Vocational Settings

Applied Research in Quality of Life -     

The internal clock: Electroencephalographic evidence for oscillatory processes underlying time perception

It has been proposed that temporal perception and performance depend on a biological source of temporal information. A model for a temporal oscillator put forward by Treisman, Faulkner, Naish, and Brogan (1990) predicted that if intense sensory pulses (such as auditory clicks) were presented to subjects at suitable rates they would perturb the frequency at which the temporal oscillator runs and so cause over- or underestimation of time. The resulting pattern of interference between sensory pulse rates and time judgments would depend on the frequency of the temporal oscillator and so might allow that frequency to be estimated. Such interference patterns were found using auditory clicks and visual flicker (Treisman & Brogan, 1992; Treisman et al., 1990). The present study examines time estimation together with the simultaneously recorded electroencephalogram to examine whether evidence of such an interference pattern can be found in the EEG.

Alternative models for the organization of a temporal system consisting of an oscillator or multiple oscillators are considered and predictions derived from them relating to the EEG. An experiment was run in which time intervals were presented for estimation, auditory clicks being given during those intervals, and the EEG was recorded concurrently. Analyses of the EEG revealed interactions between auditory click rates and certain EEG components which parallel the interference patterns previously found. The overall pattern of EEG results is interpreted as favouring a model for the organization of the temporal system in which sets of click-sensitive oscillators spaced at intervals of about 12.8 Hz contribute to the EEG spectrum. These are taken to represent a series of harmonically spaced distributions of oscillators involved in time-keeping.