Gaze stability of observers watching Op Art pictures

It has been the matter of some debate why we can experience vivid dynamic illusions when looking at static pictures composed from simple black and white patterns. The impression of illusory motion is particularly strong when viewing some of the works of 'Op Artists, such as Bridget Riley's painting Fall. Explanations of the illusory motion have ranged from retinal to cortical mechanisms, and an important role has been attributed to eye movements. To assess the possible contribution of eye movements to the illusory-motion percept we studied the strength of the illusion under different viewing conditions, and analysed the gaze stability of observers viewing the Riley painting and control patterns that do not produce the illusion. Whereas the illusion was reduced, but not abolished, when watching the painting through a pinhole, which reduces the effects of accommodation, it was not perceived in flash afterimages, suggesting an important role for eye movements in generating the illusion for this image. Recordings of eye movements revealed an abundance of small involuntary saccades when looking at the Riley pattern, despite the fact that gaze was kept within the dedicated fixation region. The frequency and particular characteristics of these rapid eye movements can vary considerably between different observers, but, although there was a tendency for gaze stability to deteriorate while viewing a Riley painting, there was no significant difference in saccade frequency between the stimulus and control patterns. Theoretical considerations indicate that such small image displacements can generate patterns of motion signals in a motion-detector network, which may serve as a simple and sufficient, but not necessarily exclusive, explanation for the illusion. Why such image displacements lead to perceptual results with a group of Op Art and similar patterns, but remain invisible for other stimuli, is discussed.     

The role of item-specific information for the serial position curve in free recall

The serial position curve in free recall of a list of action phrases differs depending on whether the phrases were memorized by listening/reading (verbal task; VT) or by additionally enacting the denoted actions (subject-performed task; SPT). In VTs there is a clear primacy effect and a short recency effect. In SPTs there is no primacy effect but an extended recency effect. H. D. Zimmer, T. Helstrup, and J. Engelkamp (2000) assumed that SPTs provide excellent item-specific information, which leads to an automatic pop-out of the items presented last. In the present study, the authors assumed that good item-specific encoding generally enhances the recency effect and that it hinders rehearsal processes and thereby reduces the primacy effect. This assumption was confirmed. An item-specific orienting task leads to parallel serial position curves in VTs and SPTs with no primacy effect but a clear recency effect. Moreover, the same serial position effects were shown with nouns as learning material. An item-specific orienting task changes the classical U-shaped serial position curve with verbal material and leads to the disappearance of the primacy and the enhancement of the recency effect.     

The Determinables Of Explanatory Mechanisms

Sometimes instances of perceived causation turn out to lack causal relata. The reasons may vary. Causation may display itself as prevention, or as omission, and in some cases causation occurs within such complex environments that few of the things we associate with causes and effects are true of them, etc. But even then, there may be causal explanations to be had. This suggests that the explanatory power of causal reports have other sources than the relation between cause and effect. In this paper it is argued that the causal mechanisms we allude to in explanations have relevant determinables other than the traditionally acknowledged ones. The traditional but in this aspect mistaken view of causation is to be blamed. Discernability, complexity of manifestation, originality, and even stability have often been overlooked. We know, that, in fact, heat is a constant attendant of flame; but what is the connexion between them, we have no room so much as to conjecture or imagine. (Hume 1777, VII. 2, 64) This revised version was published online in June 2006 with corrections to the Cover Date.     

Empfehlungen zur Behandlungspraxis bei psychotherapeutischen Kriseninterventionen

Ohne Zusammenfassung     

SCRIPTKELL: A tool for measuring cognitive effort and time processing in writing and other complex cognitive activities

We present SCRIPTKELL, a computer-assisted experimental tool that makes it possible to measure the time and cognitive effort allocated to the subprocesses of writing and other cognitive activities. SCRIPTKELL was designed to easily use and modulate Kellogg’s (1986) triple-task procedure, which consists of a combination of three tasks: a writing task (or another task), a reaction time task (auditory signal detection), and a directed retrospection task (after each signal detection during writing). We demonstrate how this tool can be used to address several novel empirical and theoretical issues. In sum, SCRIPTKELL should facilitate the flexible realization of experimental designs and the investigation of critical issues concerning the functional characteristics of complex cognitive activities.     

Behandlung und Teamprozesse in der stationären Psychotherapie

Ohne Zusammenfassung     

Power at work: Linking objective power to psychological power

Experimental research conducted with student participants has documented that feeling powerful or powerless (psychological power) affects outcomes with high practical relevance for organizations. However, it is unclear how results from these studies can be generalized to organizational settings in which individuals have various roles that imply more or less objective power. To address this gap, we present a theoretical framework to aid in the understanding of how objective power in organizations affects psychological power. We assume that stable differences in organizational rank (i.e., structural power) determine the likelihood of interactions with superiors, subordinates, or peers. These interactions give rise to within-person variation in situational power which should lead to dynamic fluctuations of psychological power and eventually its outcomes. Results of a preregistered experiment (n = 190 participants) and a preregistered experience sampling study (n = 129 participants) conducted with working adults support our key predictions: Structural power was associated with the likelihood of being in a high power versus low power situation. Within-person differences in situational power were related to feelings of power such as judgments about (1) one's own ability to influence others in a given social situation (i.e., interpersonal power) and (2) one's own competence, agency, autonomy, and independence (i.e., personal power).