Identifying individuality and variability in team tactics by means of statistical shape analysis and multilayer perceptrons

Offensive and defensive systems of play represent important aspects of team sports. They include the players' positions at certain situations during a match, i.e., when players have to be on specific positions on the court. Patterns of play emerge based on the formations of the players on the court. Recognition of these patterns is important to react adequately and to adjust own strategies to the opponent. Furthermore, the ability to apply variable patterns of play seems to be promising since they make it harder for the opponent to adjust. The purpose of this study is to identify different team tactical patterns in volleyball and to analyze differences in variability. Overall 120 standard situations of six national teams in women's volleyball are analyzed during a world championship tournament. Twenty situations from each national team are chosen, including the base defence position (start configuration) and the two players block with middle back deep (end configuration). The shapes of the defence formations at the start and end configurations during the defence of each national team as well as the variability of these defence formations are statistically analyzed. Furthermore these shapes data are used to train multilayer perceptrons in order to test whether artificial neural networks can recognize the teams by their tactical patterns. Results show significant differences between the national teams in both the base defence position at the start and the two players block with middle back deep at the end of the standard defence situation. Furthermore, the national teams show significant differences in variability of the defence systems and start-positions are more variable than the end-positions. Multilayer perceptrons are able to recognize the teams at an average of 98.5%. It is concluded that defence systems in team sports are highly individual at a competitive level and variable even in standard situations. Artificial neural networks can be used to recognize teams by the shapes of the players' configurations. These findings support the concept that tactics and strategy have to be adapted for the team and need to be flexible in order to be successful.     

Representing others' actions: the role of expertise in the aging mind

A large body of evidence suggests that action execution and action observation share a common representational domain. To date, little is known about age-related changes in these action representations that are assumed to support various abilities such as the prediction of observed actions. The purpose of the present study was to investigate (a) how age affects the ability to predict the time course of observed actions; and (b) whether and to what extent sensorimotor expertise attenuates age-related declines in prediction performance. In a first experiment, older adults predicted the time course of familiar everyday actions less precisely than younger adults. In a second experiment, younger and older figure skating experts as well as age-matched novices were asked to predict the time course of figure skating elements and simple movement exercises. Both young age and sensorimotor expertise had a positive influence on prediction performance of figure skating elements. The expertise-related benefit did not show a transfer to movement exercises. Together, the results suggest a specific decline of action representations in the aging mind. However, extensive sensorimotor experience seems to enable experts to represent actions from their domain of expertise more precisely even in older age.     

Common patterns of prediction of literacy development in different alphabetic orthographies

Previous studies have shown that phoneme awareness, letter-sound knowledge, rapid automatized naming (RAN), and verbal memory span are reliable correlates of learning to read in English. However, the extent to which these different predictors have the same relative importance in different languages remains uncertain. In this article, we present the results from a 10-month longitudinal study that began just before or soon after the start of formal literacy instruction in four languages (English, Spanish, Slovak, and Czech). Longitudinal path analyses showed that phoneme awareness, letter-sound knowledge, and RAN (but not verbal memory span) measured at the onset of literacy instruction were reliable predictors, with similar relative importance, of later reading and spelling skills across the four languages. These data support the suggestion that in all alphabetic orthographies, phoneme awareness, letter-sound knowledge, and RAN may tap cognitive processes that are important for learning to read.     

Verbal descriptions of spatial information can interfere with picture processing

Two studies are reported that tested the assumption that learning is improved by presenting text and pictures compared to text only when the text conveys non-spatial rather than spatial information. In Experiment 1, 59 students learned with text containing either visual or spatial contents, both accompanied by the same pictures. The results confirmed the expected interference between the processing of spatial text contents and pictures: Learners who received text containing spatial information showed worse text and picture recall than learners who received text containing visual information. In Experiment 2, 85 students were randomly assigned to one of four conditions, which resulted from a 2×2 between-participants design, with picture presentation (with vs without) and text contents (visual vs spatial) as between-participants factors. Again the results confirmed the expected interference between processing of spatial text information and pictures, because beneficial effects of adding pictures to text were observed only when the texts conveyed visual information. Importantly, when no pictures were present no differences were observed between learners with either visual or spatial texts contents, indicating that the observed effects are not caused by absolute differences between the two texts such as their difficulty. The implications of these results are discussed.     

The Illness/Injury Sensitivity Index: Validation of a German Version of the ISI-R

Three fundamental fears-anxiety sensitivity, fear of negative evaluation, and illness/injury sensitivity-are considered integral components of anxiety-related psychopathology and also bear connections with chronic pain. Scales measuring the first two fears, the Anxiety Sensitivity Index and the Fear of Negative Evaluation Scale, have been translated into German; however, the nine-item Illness/Injury Sensitivity Index-Revised (ISI-R) that measures fears of injury and illness has not been available in German language yet. The aim of this study therefore was a translation of the ISI-R into German language and an initial validation of the translated scale in two different samples. The German ISI-R was translated by both professionals and laypersons, and a final version was decided on by consensus. In Study 1, participants included 96 undergraduate students (85% women) who completed the German version of the ISI as part of a larger study. An exploratory factor analysis with oblique rotation was conducted and suggested a two-factor-solution with one factor representing fears of illness and the other fears of injury. This factor structure was confirmed via a confirmatory factor analysis (CFA) in Study 2. Participants included 117 community members (79% women). Convergent validity was supported using a visual analogue scale for fear of illness in both samples and the German translation of the Whiteley Index in Study. Overall, the results supported the German translation of the ISI-R. Comprehensive results, limitations, and directions for future research are discussed.     

The interleaving of actions in everyday life multitasking demands

It has been argued that executive tests should capture central aspects of executive functions in everyday life such as initiating and monitoring parallel actions in low-structured environments (so-called multitasking; see Burgess, 2000). We present a cooking task in order to assess executive function impairments in brain-damaged patients, which focuses on a central feature of multitasking, the interleaving of tasks (Burgess, 2000). Behavioural performance of 21 brain-damaged patients (stroke, traumatic brain injury) and of a group of matched controls was analysed on the basis of a standardized protocol. In comparison to controls, the patients explored less, were less successful in monitoring their actions and corrected errors less efficiently. Interleaving of actions was observed less frequently in patients, with respect to both cooking itself as well as to subordinate goals (e.g., cleaning up). Interleaving proved efficient, as it was associated with less time to complete the task. Patients' scores in the cooking task correlated with performance in both the Behavioural Assessment of the Dysexecutive Syndrome (BADS) Zoo Map Test and the BADS Six Elements Test, but not with tests of attention, verbal memory, or figural fluency, thus demonstrating convergent and discriminant validity. In summary, our task demonstrates that cooking can provide a valid testing ground for assessing a central aspect of everyday multitasking demands, namely, the interleaving of actions.     

Is it possible to prepare the second component of a movement before the first one?

Experiment 1 utilized a choice reaction time paradigm to examine whether advance information about the second component of a movement has similar effects upon movement initiation and execution as advance information about the first component. Four stimuli were assigned to four goal keys. Subjects responded with the index finger of their preferred hand. They had to press on of two intermediate keys before pressing the assigned stimulus goal key. Advance information signaled one pair of goal keys in such a way that either the first or the second movement component was unequivocally specified before the response signal appeared. Shorter reaction times resulted when the first component was precued. Further control conditions showed that advance information about the second movement component could not be utilized for movement preparation. Experiment 2 ruled out a perceptual interpretation of this effect. Experiment 3 showed that preparation time for two-component movements are longer than for one-component movements. The study permits the conclusions that speeded two-component movements are controlled by motor programs and that advance information about the first movement component is required before the second movement component can be programmed.