A model of saccadic landing positions in reading under the influence of sensory noise

During reading, saccadic eye movements are produced to move the high acuity foveal region of the eye to words of interest for efficient word processing. Distributions of saccadic landing positions peak close to a word's centre but are relatively broad compared to simple oculomotor tasks. Moreover, landing-position distributions are modulated both by distance of the launch site and by saccade type (e.g., one-step saccade, word skipping, refixation). Here we present a mathematical model for the computation of a saccade intended for a given target word. Two fundamental assumptions are related to (1) the sensory computation of the word centre from inter-word spaces and (2) the integration of sensory information and a priori knowledge using Bayesian estimation. Our model was developed for data from a large corpus of eye movements from normal reading. We demonstrate that the model is able simultaneously to account for a systematic shift of saccadic mean landing position with increasing launch-site distance and for qualitative differences between one-step saccades (i.e., from a given word to the next word) and word-skipping saccades.     

Contemporary theories of 1/f noise in motor control

1/f noise has been discovered in a number of time series collected in psychological and behavioral experiments. This ubiquitous phenomenon has been ignored for a long time and classical models were not designed for accounting for these long-range correlations. The aim of this paper is to present and discuss contrasted theoretical perspectives on 1/f noise, in order to provide a comprehensive overview of current debates in this domain. In a first part, we propose a formal definition of the phenomenon of 1/f noise, and we present some commonly used methods for measuring long-range correlations in time series. In a second part, we develop a theoretical position that considers 1/f noise as the hallmark of system complexity. From this point of view, 1/f noise emerges from the coordination of the many elements that compose the system. In a third part, we present a theoretical counterpoint suggesting that 1/f noise could emerge from localized sources within the system. In conclusion, we try to draw some lines of reasoning for going beyond the opposition between these two approaches.     

Grasping of extrafoveal targets: A robotic model

We present a computational model of grasping of non-fixated (extrafoveal) target objects which is implemented on a robot setup, consisting of a robot arm with cameras and gripper. This model is based on the premotor theory of attention (Rizzolatti et al., 1994) which states that spatial attention is a consequence of the preparation of goal-directed, spatially coded movements (especially saccadic eye movements). In our model, we add the hypothesis that saccade planning is accompanied by the prediction of the retinal images after the saccade. The foveal region of these predicted images can be used to determine the orientation and shape of objects at the target location of the attention shift. This information is necessary for precise grasping. Our model consists of a saccade controller for target fixation, a visual forward model for the prediction of retinal images, and an arm controller which generates arm postures for grasping. We compare the precision of the robotic model in different task conditions, among them grasping (1) towards fixated target objects using the actual retinal images, (2) towards non-fixated target objects using visual prediction, and (3) towards non-fixated target objects without visual prediction. The first and second setting result in good grasping performance, while the third setting causes considerable errors of the gripper orientation, demonstrating that visual prediction might be an important component of eye–hand coordination. Finally, based on the present study we argue that the use of robots is a valuable research methodology within psychology.     

Psychotherapie auf Palliativstationen

Exemplary for psychotherapeutic activity in the ??sphere of death?? the article focuses on the present situation of psychotherapists working on palliative care units in Germany. For that a questionnaire has been developed which includes 17 items dealing with fields of concrete psychotherapeutic work, psychotherapy training, relations with teams and institutions, subjectively felt burden and contentment etc. The questionnaire was sent to most of the German palliative care infirmaries. There is a high presence of psychotherapists in these units who are well trained in different therapeutic methods, numerically led by behavior therapy and non-directive therapy. In addition most colleagues are qualified in psychooncology and specialized pain management. Surprisingly topics, such as death or spirituality are not so often found in therapeutic contacts as would be expected. Furthermore there is a rather negative outlook on the preparation for the palliative working field during psychotherapy training. This requires extensions and supplementary curricula concerning existential themes in psychotherapy. The psychotherapists feel well integrated in their therapeutic teams but many of them have a feeling of at best a mediocre appreciation in their institutions. In spite of the difficult and stressful work the general job satisfaction is stated as high to very high.     

Perceptual grouping in haptic search: The influence of proximity, similarity, and good continuation

We conducted a haptic search experiment to investigate the influence of the Gestalt principles of proximity, similarity, and good continuation. We expected faster search when the distractors could be grouped. We chose edges at different orientations as stimuli because they are processed similarly in the haptic and visual modality. We therefore expected the principles of similarity and good continuation to be operational in haptics as they are in vision. In contrast, because of differences in spatial processing between vision and haptics, we expected differences for the principle of proximity. In haptics, the Gestalt principle of proximity could operate at two distinct levels-somatotopic proximity or spatial proximity-and we assessed both possibilities in our experiments. The results show that the principles of similarity and good continuation indeed operate in this haptic search task. Neither of our proximity manipulations yielded effects, which may suggest that grouping by proximity must take place before an invariant representation of the object has formed. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Klinisch-psychologische Intervention im Internet

Background

Currently a multitude of Internet-based intervention (IBI) programs exist for various disorders. These programs generally have the potential to reach a wide spectrum of the low threshold population and encourage them to play a more active role in managing individual healthcare. How effective are disorder and problem-specific IBI programs? This review aims to give a systematic overview of controlled evaluation studies available to date and contrast them with the state of research in 2003 (Ott 2003).

Method

References were analyzed in three steps: 1. Research in pertinent international scientific databases using specified keywords (result: more than 1,000 publications since 2003). 2. Selection: exclusion of publications which did not contain empirical evidence of effectiveness (with control group design) (result: 89 studies published between 2003 and 2009 as opposed to 30 up to 2003). 3. Systemization: classification of the analyzed studies based on two dimensions (type of syndrome, function of intervention).

Results

In most of the studies on hand (91.0%) the effectiveness of IBI could be confirmed. Among the methods used cognitive behavioral methods (cognitive, behavioral therapy, CBT) were used almost exclusively. In nearly three quarters of all studies (71.9%), IBI procedures were used for treatment. The remaining studies were on prevention (19.1%) and rehabilitation (9.0%).

Conclusion

Evaluation studies of IBIs are now available, particularly for anxiety disorders, depression, posttraumatic stress disorder, eating disorders including adiposity, substance-related and behavioral medical disorders, psychological problems related to physical illnesses, compulsive gambling and burnout. For each type of disorder, exemplary programs are described. Subsequently the methodical limitations of several of the studies are pointed out.