Lösungsstrategien beim Attneaveschen Rateversuch

Zusammenfassung Der Rateversuch von Attneave wurde durch Zulassung freier Ratestrategien modifiziert und der Lösungsvorgang der Rateaufgabe zum Thema einer Untersuchung gemacht. Es zeigte sich, daß die Rateleistung (Position des letzten Fehlers) mit zwei provisorisch gebildeten Strategiemerkmalen kovariiert: der Systematik der Abfolge und dem Verhalten nach einem Fehler. Je weniger systematisch die Reihenfolge überprüfter Flächenelemente ist oder/und je konsequenter die positive Strategie der Suche nach dem Figurverlauf auch nach der Widerlegung von Teilhypothesen beibehalten wird, um so besser ist die Rateleistung. Die Befunde werden kurz diskutiert.     

Acquiring a Taste: Alcohol Experiences of German Elementary School Children

Few data are available on alcohol experiences among elementary school children, although early onset and trying of alcohol use is known to be a risk factor for adolescent alcohol abuse. Until now, research leaves open the question on which factors encourage early trying behavior. In a cross-sectional study design, a written survey was conducted in 49 randomly selected elementary schools in Germany. The survey was carried out among 3rd and 4th graders with a median age of 9 years during class time in the school year 2010/2011. 1806 questionnaires were included in the study. The risk behavior of having tried alcohol was analyzed. A total of 37.7% (n = 681) of all children reported to have already tried alcohol. While grade and age had no significant influence in the final multivariate model, the gender effect stayed relevant (Male: aOR 1.2, 95%-CI 1.0–1.5), as did the question of whether the child liked going to school (No: aOR 1.4, 95%-CI 1.1–1.7), a lack of parental monitoring (aOR 1.5, 95%-CI 1.1–2.1), consistent parenting (Sometimes/never: aOR 1.5, 95%-CI 1.1–1.9), a regularly provided break-time snack (No: aOR 2.2, 95%-CI 1.3–3.8), as well as parents’ drinking (Yes: aOR 2.0, 95%-CI 1.6–2.6) and drinking among peers (Yes: aOR 8.5, 95%-CI 6.2–11.6). Our study shows that alcohol experiences can be highly prevalent among 3rd and 4th grade elementary school children in Germany. Our findings suggest that especially those variables which may be controlled by the parents are strongly associated with children’s alcohol experiences suggesting a starting point for preventative intervention measures. The results also indicate the need for innovative gender-sensitive approaches in the living environment of elementary school children.     

Measuring perceived ceiling height in a visual comparison task

When judging interior space, a dark ceiling is judged to be lower than a light ceiling. The method of metric judgments (e.g., on a centimetre scale) that has typically been used in such tasks may reflect a genuine perceptual effect or it may reflect a cognitively mediated impression. We employed a height-matching method in which perceived ceiling height had to be matched with an adjustable pillar, thus obtaining psychometric functions that allowed for an estimation of the point of subjective equality (PSE) and the difference limen (DL). The height-matching method developed in this paper allows for a direct visual match and does not require metric judgment. It has the added advantage of providing superior precision. Experiment 1 used ceiling heights between 2.90?m and 3.00?m. The PSE proved sensitive to slight changes in perceived ceiling height. The DL was about 3% of the physical ceiling height. Experiment 2 found similar results for lower (2.30?m to 2.50?m) and higher (3.30?m to 3.50?m) ceilings. In Experiment 3, we additionally varied ceiling lightness (light grey vs. dark grey). The height matches showed that the light ceiling appeared significantly higher than the darker ceiling. We therefore attribute the influence of ceiling lightness on perceived ceiling height to a direct perceptual rather than a cognitive effect.     

Verbal-Motor Attention-Focusing Instructions Influence Kinematics and Performance on a Golf-Putting Task

The authors examined how varying the content of verbal-motor instructions and requesting an internal versus external focus influenced the kinematics and outcome of a golf putting task. On Day 1, 30 novices performed 120 trials with the instruction to focus attention either on performing a pendulum-like movement (internal) or on the desired ball path (external). After 20 retention trials on Day 2, they performed 20 transfer trials with the opposite instruction. Group differences for retention and a group by block interaction showed that external instruction enhanced movement outcome. Kinematic data indicated that specific instruction content influenced outcomes by eliciting changes in movement execution. Switching from the external to the internal focus instruction resulted in a more pendulum-like movement.     

The Functional Role of Cognitive Frameworks on Visuomotor Adaptation Performance

The authors investigated the effects of cognitive representations of movement directions on sensorimotor adaptation performance. Adaptation performance was measured via a pointing experiment in which participants were provided with visual feedback that was distorted along the midsagittal plane (i.e., left-right reversal). Performance was analyzed relative to participants’ individual adaptation gains and 3 groups were subsequently defined (i.e., skilled, average, and poor adapters). The group separation was kept for the Cognitive Measurement of Represented Directions, which was used to analyze participants’ cognitive representation of movement directions. The results showed that skilled adapters, in contrast to poor adapters, possess a global representation of movement directions aligned to the cardinal axes. The cognitive representation structure hence supports the sensorimotor adaptation performance.     

Model for a flexible motor memory based on a self-active recurrent neural network

Using recent recurrent network architecture based on the reservoir computing approach, we propose and numerically simulate a model that is focused on the aspects of a flexible motor memory for the storage of elementary movement patterns into the synaptic weights of a neural network, so that the patterns can be retrieved at any time by simple static commands. The resulting motor memory is flexible in that it is capable to continuously modulate the stored patterns. The modulation consists in an approximately linear inter- and extrapolation, generating a large space of possible movements that have not been learned before. A recurrent network of thousand neurons is trained in a manner that corresponds to a realistic exercising scenario, with experimentally measured muscular activations and with kinetic data representing proprioceptive feedback. The network is “self-active” in that it maintains recurrent flow of activation even in the absence of input, a feature that resembles the “resting-state activity” found in the human and animal brain. The model involves the concept of “neural outsourcing” which amounts to the permanent shifting of computational load from higher to lower-level neural structures, which might help to explain why humans are able to execute learned skills in a fluent and flexible manner without the need for attention to the details of the movement.     

Impaired visual perception of hurtful actions in patients with chronic low back pain

Visually presented biological motion stimuli activate regions in the brain that are also related to musculo-skeletal pain. We therefore hypothesized that chronic pain impairs the perception of visually presented actions that involve body parts that hurt. In the first experiment, chronic back pain (CLBP) patients and healthy controls judged the lifted weight from point-light biological motion displays. An actor either lifted an invisible container (5, 10, or 15 kg) from the floor, or lifted and manipulated it from the right to the left. The latter involved twisting of the lower back and would be very painful for CLBP patients. All participants recognized the displayed actions, but CLBP patients were impaired in judging the difference in handled weights, especially for the trunk rotation. The second experiment involved discrimination between forward and backward walking. Here the patients were just as good as the controls, showing that the main result of the first experiment was indeed specific to the sensory aspects of the task, and not to general impairments or attentional deficits. The results thus indicate that the judgment of sensorimotor aspects of a visually displayed movement is specifically affected by chronic low back pain.     

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.