The impact of self-generated and explicitly acquired contextual knowledge on anticipatory performance.

The present study aimed to investigate the impact of self-generated and explicitly acquired contextual knowledge of teammates' defensive qualities on anticipatory performance in a complex sensorimotor task. Twelve expert and twelve near-expert handball players were examined in a domain-specific defence task presented in an immersive virtual-reality environment. In two-thirds of the trials, 1:1 situations (i.e., teammate versus opponent) were presented in which the teammates next to the participant played a specific role. Whilst the weak teammate lost every situation, which required the participant to block a throw, the strong teammate won every situation, which required the participant to stay in his position. Since explicit knowledge of this pattern was only provided in a later phase of the experiment, participants would have to generate the respective knowledge themselves beforehand. To this end, the following variables were analysed: the detection of experimentally induced patterns, the correctness of the participants' motor responses and their positioning as a function of the respective teammate's defensive quality. Main results showed that experts are better able to utilize both self-generated as well as explicitly acquired knowledge regarding teammates' defensive qualities, whereas near-experts' performance was enhanced only by explicitly provided contextual knowledge.

The role of viewing distance and viewing angle on referees' decision-making performance during the FIFA World Cup 2014.

The present study aims to reveal the effects of positioning on decision-making performance in top-level refereeing in association football. To this end, for all 64 matches of the FIFA World Cup 2014, potential foul-play situations were videometrically analysed in terms of the referee's position relative to the infringement. Contrary to earlier studies, viewing angles were analysed in addition to viewing distances and error rates were considered for not only falsely whistled but also falsely non-whistled events. Moreover, direct logistic regression analysis was applied to detect position-dependent differences. For the total of 1,527 potential foul play situations, an overall low error rate of 6.9% was found. The similar numbers of total whistle (n = 52) and non-whistle errors (n = 54) reflect referees' ability to balance both types of errors. Regarding the overall viewing-distance effect, referees were 2.58 times (95% CI 1.47-4.54) more likely to commit a whistle error at 10-15 m and 5.51 times (95% CI 1.35-22.47) more likely to commit a non-whistle error at 0-5 m, corresponding to the position ranges occurring with the highest (10-15 m: 30.3%) and lowest (0-5 m: 5.8%) frequencies. In contrast, no significant effects of viewing-angle on decision-making accuracy could be revealed.

Peripheral Vision in Martial Arts Experts: The Cost-Dependent Anchoring of Gaze.

Research on martial arts has suggested that gaze anchoring is functional for optimizing the use of peripheral visual information. The current study predicted that the height of gaze anchoring on the opponent's body would depend on the potential attacking locations that need to be monitored. To test this prediction, the authors compared high-level athletes in kung fu (Qwan Ki Do), who attack with their arms and legs, with Tae Kwon Do fighters, who attack mostly with their legs. As predicted, the results show that Qwan Ki Do athletes anchor their gaze higher than Tae Kwon Do athletes do before and even during the first attack. In addition, gaze anchoring seems to depend on 3 factors: the particulars of the evolving situation, crucial cues, and specific visual costs (especially suppressed information pickup during saccades). These 3 factors should be considered in future studies on gaze behavior in sports to find the most functional, that is, cost-benefit-optimized, gaze pattern.

Quiet Eye and Motor Performance: The Longer the Better?

The quiet-eye (QE) phenomenon has been found to predict subsequent motor performance. However, it remains unclear whether this effect also holds for considerably extended QE durations. Therefore, in 2 ball-throwing studies, QE durations of 400-3,200 ms were experimentally induced. Inferior performance was found in short QE-duration conditions; however, there was no difference between the long QE-duration conditions. Extrapolations beyond the observed QE values showed performance gains up to 2,000 ms and a shallow interval of optimality at a QE duration of about 3,000 ms. These results, together with the fact that the intended absolute QE durations were not achieved, point toward an inhibition explanation of the QE. Thus, the initial performance gain is interpreted as shielding of the movement parameterization against suboptimal alternatives, whereas the performance loss due to very long QE durations is ascribed to mutually balancing the processes of shielding and environmental monitoring.

Disentangling vision and attention in multiple-object tracking: How crowding and collisions affect gaze anchoring and dual-task performance.

Previous studies of multiple-object tracking have shown that gaze behavior is affected by target collisions and target-distractor crowding. Therefore, in order to experimentally disentangle this collision-crowding confound, we examined events of target collisions with the bordering frame and crowding with distractors. We hypothesized that collisions are particularly demanding for covert attentional processing, whereas crowding particularly challenges peripheral vision. Results show that gaze is located closer to targets when they are crowded, as would be expected to reduce negative crowding effects by utilizing the higher spatial acuity of foveal vision. However, saccades, which interrupt visual information processing, were instead initiated as a function of target collisions with the bordering frame. Consequently, in a dual-task condition that required the detection of target changes, participants more frequently missed changes if they occurred in time intervals around a collision. Based on these results, superior performance should be expected if foveal gaze is optimally anchored among crowded targets and if potential target changes are monitored with peripheral vision. In addition to the implications for further laboratory research of multiple-object tracking, these findings are relevant to a multitude tasks that require the monitoring of several targets and the simultaneous detection of certain events in the visual periphery, as it is commonly the case, for instance, in sports.

Direction detection thresholds of passive self-motion in artistic gymnasts.

In this study, we compared direction detection thresholds of passive self-motion in the dark between artistic gymnasts and controls. Twenty-four professional female artistic gymnasts (ranging from 7 to 20 years) and age-matched controls were seated on a motion platform and asked to discriminate the direction of angular (yaw, pitch, roll) and linear (leftward-rightward) motion. Gymnasts showed lower thresholds for the linear leftward-rightward motion. Interestingly, there was no difference for the angular motions. These results show that the outstanding self-motion abilities in artistic gymnasts are not related to an overall higher sensitivity in self-motion perception. With respect to vestibular processing, our results suggest that gymnastic expertise is exclusively linked to superior interpretation of otolith signals when no change in canal signals is present. In addition, thresholds were overall lower for the older (14-20 years) than for the younger (7-13 years) participants, indicating the maturation of vestibular sensitivity from childhood to adolescence.

On the interaction of attentional focus and gaze: the quiet eye inhibits focus-related performance decrements.

To date, despite a large body of evidence in favor of the advantage of an effect-related focus of attention compared with a movement-related focus of attention in motor control and learning, the role of vision in this context remains unclear. Therefore, in a golf-putting study, the relation between attentional focus and gaze behavior (in particular, quiet eye, or QE) was investigated. First, the advantage of an effect-related focus, as well as of a long QE duration, could be replicated. Furthermore, in the online-demanding task of golf putting, high performance was associated with later QE offsets. Most decisively, an interaction between attentional focus and gaze behavior was revealed in such a way that the efficiency of the QE selectively manifested under movement-related focus instructions. As these findings suggest neither additive effects nor a causal chain, an alternative hypothesis is introduced explaining positive QE effects by the inhibition of not-to-be parameterized movement variants.

How spotting technique affects dizziness and postural stability after full-body rotations in dancers.

Consecutive longitudinal axis rotations are very common in dance, ranging from head spins in break dance to pirouettes in ballet. They pose a rather formidable perceptuomotor challenge - and hence form an interesting window into human motor behaviour - yet they have been scarcely studied. In the present study, we investigated dancers' dizziness and postural stability after consecutive rotations. Rotations were performed actively or undergone passively, either with or without the use of a spotting technique in such an order that all 24 ordering options were offered at least once and not more than twice. Thirty-four dancers trained in ballet and/or contemporary dance (aged 27.2 ± 5.1 years) with a mean dance experience of 14.2 ± 7.1 years actively performed 14 revolutions in passé or coupé positions with a short gesture leg "foot down" after each revolution. In addition, they were passively turned through 14 revolutions on a motor-driven rotating chair. Participants' centre-of-pressure (COP) displacement was measured on a force-plate before and after the rotations. Moreover, the dancers indicated their subjective feeling of dizziness on a scale from 0 to 20 directly after the rotations. Both the active and passive conditions were completed with and without the dancers spotting. As expected, dizziness was worse after rotations without the adoption of the spotting technique, both in active and passive rotations. However, the pre-post difference in COP area after active rotations was unaffected by spotting, whereas in the passive condition, spotting diminished this difference. Our results thus suggest that adopting the spotting technique is a useful tool for dizziness reduction in dancers who have to perform multiple rotations. Moreover, spotting appears most beneficial for postural stability when it involves less postural control challenges, such as when seated on a chair and occurs in situations with limited somatosensory feedback (e.g., from the cutaneous receptors in the feet). However, the unexpected finding that spotting did not help postural stability after active rotations needs to be investigated further in future studies, for example with a detailed analysis of whole-body kinematics and eye-tracking.

Eye-tracking technology and the dynamics of natural gaze behavior in sports: an update 2016-2022.

Updating and complementing a previous review on eye-tracking technology and the dynamics of natural gaze behavior in sports, this short review focuses on the progress concerning researched sports tasks, applied methods of gaze data collection and analysis as well as derived gaze measures for the time interval of 2016-2022. To that end, a systematic review according to the PRISMA guidelines was conducted, searching Web of Science, PubMed Central, SPORTDiscus, and ScienceDirect for the keywords: eye tracking, gaze behavio*r, eye movement, and visual search. Thirty-one studies were identified for the review. On the one hand, a generally increased research interest and a wider area of researched sports with a particular increase in official's gaze behavior were diagnosed. On the other hand, a general lack of progress concerning sample sizes, amounts of trials, employed eye-tracking technology and gaze analysis procedures must be acknowledged. Nevertheless, first attempts to automated gaze-cue-allocations (GCA) in mobile eye-tracking studies were seen, potentially enhancing objectivity, and alleviating the burden of manual workload inherently associated with conventional gaze analyses. Reinforcing the claims of the previous review, this review concludes by describing four distinct technological approaches to automating GCA, some of which are specifically suited to tackle the validity and generalizability issues associated with the current limitations of mobile eye-tracking studies on natural gaze behavior in sports.

Beyond task-space exploration: On the role of variance for motor control and learning.

This conceptual analysis on the role of variance for motor control and learning should be taken as a call to: (a) overcome the classic motor-action controversy by identifying converging lines and mutual synergies in the explanation of motor behavior phenomena, and (b) design more empirical research on low-level operational aspects of motor behavior rather than on high-level theoretical terms. Throughout the paper, claim (a) is exemplified by deploying the well-accepted task-space landscape metaphor. This approach provides an illustration not only of a dynamical sensorimotor system but also of a structure of internal forward models, as they are used in more cognitively rooted frameworks such as the theory of optimal feedback control. Claim (b) is put into practice by, mainly theoretically, substantiating a number of predictions for the role of variance in motor control and learning that can be derived from a convergent perspective. From this standpoint, it becomes obvious that variance is neither generally "good" nor generally "bad" for sensorimotor learning. Rather, the predictions derived suggest that specific forms of variance cause specific changes on permanent performance. In this endeavor, Newell's concept of task-space exploration is identified as a fundamental learning mechanism. Beyond, we highlight further predictions regarding the optimal use of variance for learning from a converging view. These predictions regard, on the one hand, additional learning mechanisms based on the task-space landscape metaphor-namely task-space formation, task-space differentiation and task-space (de-)composition-and, on the other hand, mechanisms of meta-learning that refer to handling noise as well as learning-to-learn and learning-to-adapt. Due to the character of a conceptual-analysis paper, we grant ourselves the right to be highly speculative on some issues. Thus, we would like readers to see our call mainly as an effort to stimulate both a meta-theoretical discussion on chances for convergence between classically separated lines of thought and, on an empirical level, future research on the role of variance in motor control and learning.

Learn to Turn: Does Spotting Foster Skill Acquisition in Pirouettes?

Purpose: The spotting technique (i.e., independent head from torso movement) has been revealed as the single feature that differentiates highly skilled from less-skilled dancers. In the current intervention study, the potential of a specific spotting training in novice dancers for learning double pirouettes was tested. Method: Novice dancers trained pirouettes in an experimental group and an active control group over a period of eight weeks by receiving either specific spotting instructions or technical instructions only. Pirouette performance was examined in a pretest, and a one-week-delayed retention test. In a further control test, effects of explicitly instructing how to perform the pirouettes (i.e., either with or without spotting) were investigated. Results: Different than expected, in the retention test, only few participants from the experimental group showed the spotting technique. Moreover, the spotting group did not perform better than the control group. Rather, the balance measure revealed that, while the control group improved over learning, the experimental group remained at the baseline values and showed a slight advantage for orientation only. In the control test, all groups showed inferior performance as compared to the retention test. Conclusion: In sum, the current findings show that-at least for beginners-the spotting technique is not suitable to be implemented in applied training settings. Moreover, in line with the expert performance approach, this study suggests to investigate the implementation of expert skills in applied training routines experimentally.

On the Issue of Developing Creative Players in Team Sports: A Systematic Review and Critique From a Functional Perspective.

Driven by the practical goal of developing creative players, several approaches to training creativity have been proposed and underpinned by empirical studies in sport science. However, the scope of these studies encompasses various aspects, which have all been subsumed under the singular label of "creativity." Therefore, this systematic review aims to disentangle the pursued lines of thought in order to facilitate the derivation of well-grounded recommendations for sports practice. To this end, 38 studies are presented and characterized in terms of their underlying conceptualizations and measures of creativity. In most studies, creativity is conceptualized as a player's domain-specific divergent thinking (DT) ability, reflected by individual differences in the number, variety and originality of ideas he or she is able to generate in response to game situations. Empirical studies indicate that DT can be improved by practice. However, the critical assumption that an enhanced DT ability transfers to creative on-field actions has yet to be tested. On the basis of the reviewed literature, an alternative point of view is proposed. In line with a relational understanding of creativity and a functional approach to behavioral control, it is hypothesized that an enhanced repertoire of sensorimotor skills increases the probability for performing functional solutions that, within a specific social and cultural frame of reference, go beyond the expected and consequently appear creative to the observer. In the context of sports practice, the proposed conceptual re-orientation would then suggest, rather than seeking ways to improve players' DT ability, to target sensorimotor skills that allow players to perform a variety of task-solutions and thus to act less predictably to the opponent-or in other words, more creative.

Detecting motion changes with peripheral vision: On the superiority of fixating over smooth-pursuit tracking.

Detecting motion changes is a fundamental prerequisite for solving tasks in sports and in everyday life. It is known that peripheral vision is used to detect these changes and that saccades impair detection performance. However, comparatively little is known about the role of smooth-pursuit eye-movements (SPEMs) during these tasks. Therefore, we compared peripheral motion-change detection during SPEM and fixation at eccentricities up to 18°, simulating the perceptual demands of real-life situations. Based on expert gaze behavior in sports, we predicted that motion detection should be better during fixation than SPEM. In a series of three experiments, we consistently found that detection rates and response times were impaired during SPEM compared to fixation, particularly at 18° eccentricity. With an invisible pursuit object and targets moving ahead rather than behind the pursued object, performance differences in response times declined, whereas differences in detection rates interestingly remained unmoved. We argue that retinal image motion and attentional demands are reasons for SPEM impairments.

Sleep-dependent motor memory consolidation in healthy adults: A meta-analysis.

It is widely accepted that sleep better facilitates the consolidation of motor memories than does a corresponding wake interval (King et al., 2017). However, no in-depth analysis of the various motor tasks and their relative sleep gain has been conducted so far. Therefore, the present meta-analysis considered 48 studies with a total of 53 sleep (n = 829) and 53 wake (n = 825) groups. An overall comparison between all sleep and wake groups resulted in a small effect for the relative sleep gain in motor memory consolidation (g = 0.43). While no subgroup differences were identified for differing designs, a small effect for the finger tapping task (g = 0.47) and a medium effect for the mirror tracing task (g = 0.62) were found. In summary, the meta-analysis substantiates that sleep generally benefits the consolidation of motor memories. However, to further our understanding of the mechanisms underlying this effect, examining certain task dimensions and their relative sleep gain would be a promising direction for future research.

Perception and Action in Sports. On the Functionality of Foveal and Peripheral Vision.

An optimal coupling between perception and action is crucial for successful performance in sports. In basketball, for example, a stable fixation onto the basket helps to gain precise visual information of the target to successfully throw a basketball into the basket. In basketball-defense situations, however, opposing players cutting to the basket can be detected by using peripheral vision as less precise information are sufficient to mark this player. Those examples elucidate that to solve a given task foveal and peripheral vision can be used to acquire the necessary information. Following this reasoning, the current state of our framework will be presented that allows one to predict the functionality of one or the other or both depending on the current situation and task demands. In more detail, for tasks that require high motor precision like in far-aiming tasks, empirical evidence suggests that stable foveal fixations facilitate inhibitory processes of alternative action parameterization over movement planning and control. However, more complex situations (i.e., with more than one relevant information source), require peripheral vision to process relevant information by positioning gaze at a functional location which might actually be in free space between the relevant information sources. Based on these elaborations, we will discuss complementarities, the role of visual attention as well as practical implications.

The Quiet Eye and Motor Expertise: Explaining the "Efficiency Paradox".

It has been consistently reported that experts show longer quiet eye (QE) durations when compared to near-experts and novices. However, this finding is rather paradoxical as motor expertise is characterized by an economization of motor-control processes rather than by a prolongation in response programming, a suggested explanatory mechanism of the QE phenomenon. Therefore, an inhibition hypothesis was proposed that suggests an inhibition of non-optimal task solutions over movement parametrization, which is particularly necessary in experts due to the great extent and high density of their experienced task-solution space. In the current study, the effect of the task-solution space' extension was tested by comparing the QE-duration gains in groups that trained a far-aiming task with a small number (low-extent) vs. a large number (high-extent) of task variants. After an extensive training period of more than 750 trials, both groups showed superior performance in post-test and retention test when compared to pretest and longer QE durations in post-test when compared to pretest. However, the QE durations dropped to baseline values at retention. Finally, the expected additional gain in QE duration for the high-extent group was not found and thus, the assumption of long QE durations due to an extended task-solution space was not confirmed. The findings were (by tendency) more in line with the density explanation of the inhibition hypothesis. This density argument suits research revealing a high specificity of motor skills in experts thus providing worthwhile options for future research on the paradoxical relation between the QE and motor expertise.

Detecting target changes in multiple object tracking with peripheral vision: More pronounced eccentricity effects for changes in form than in motion.

In the current study, dual-task performance is examined with multiple-object tracking as a primary task and target-change detection as a secondary task. The to-be-detected target changes in conditions of either change type (form vs. motion; Experiment 1) or change salience (stop vs. slowdown; Experiment 2), with changes occurring at either near (5°-10°) or far (15°-20°) eccentricities (Experiments 1 and 2). The aim of the study was to test whether changes can be detected solely with peripheral vision. By controlling for saccades and computing gaze distances, we could show that participants used peripheral vision to monitor the targets and, additionally, to perceive changes at both near and far eccentricities. Noticeably, gaze behavior was not affected by the actual target change. Detection rates as well as response times generally varied as a function of change condition and eccentricity, with faster detections for motion changes and near changes. However, in contrast to the effects found for motion changes, sharp declines in detection rates and increased response times were observed for form changes as a function of the eccentricities. This result can be ascribed to properties of the visual system, namely to the limited spatial acuity in the periphery and the comparably receptive motion sensitivity of peripheral vision. These findings show that peripheral vision is functional for simultaneous target monitoring and target-change detection as saccadic information suppression can be avoided and covert attention can be optimally distributed to all targets. (PsycINFO Database Record

Eye-Tracking Technology and the Dynamics of Natural Gaze Behavior in Sports: A Systematic Review of 40 Years of Research.

Reviewing 60 studies on natural gaze behavior in sports, it becomes clear that, over the last 40 years, the use of eye-tracking devices has considerably increased. Specifically, this review reveals the large variance of methods applied, analyses performed, and measures derived within the field. The results of sub-sample analyses suggest that sports-related eye-tracking research strives, on the one hand, for ecologically valid test settings (i.e., viewing conditions and response modes), while on the other, for experimental control along with high measurement accuracy (i.e., controlled test conditions with high-frequency eye-trackers linked to algorithmic analyses). To meet both demands, some promising compromises of methodological solutions have been proposed-in particular, the integration of robust mobile eye-trackers in motion-capture systems. However, as the fundamental trade-off between laboratory and field research cannot be solved by technological means, researchers need to carefully weigh the arguments for one or the other approach by accounting for the respective consequences. Nevertheless, for future research on dynamic gaze behavior in sports, further development of the current mobile eye-tracking methodology seems highly advisable to allow for the acquisition and algorithmic analyses of larger amounts of gaze-data and further, to increase the explanatory power of the derived results.

On the optimal degree of fluctuations in practice for motor learning.

In human movement science, it is widely accepted that random practice generally enhances complex motor-skill learning compared to repetitive practice. In two experiments, a particular variability-related concept is put to empirical test, namely the concept of differencial learning (DL), which assumes (i) that learners should not be distracted from task-space exploration by corrections, and (ii) that learning is facilitated by large inter-trial fluctuations. In both experiments, the advantage of DL over repetitive learning was not statistically significant. Moreover, learning was more pronounced when participants either received corrections in addition to DL (Exp. 1) or practiced in an order in which differences between consecutive trials were relatively small (Exp. 2). These findings suggest that the positive DL effects reported in literature cannot be attributed to the reduction of feedback or to the increase of inter-trial fluctuations. These results are discussed in the light of the structural-learning approach and the two-state model of motor learning in which structure-related learning effects are distinguished from the capability to adapt to current changes.

Detecting single-target changes in multiple object tracking: The case of peripheral vision.

In the present study, we investigated whether peripheral vision can be used to monitor multiple moving objects and to detect single-target changes. For this purpose, in Experiment 1, a modified multiple object tracking (MOT) setup with a large projection screen and a constant-position centroid phase had to be checked first. Classical findings regarding the use of a virtual centroid to track multiple objects and the dependency of tracking accuracy on target speed could be successfully replicated. Thereafter, the main experimental variations regarding the manipulation of to-be-detected target changes could be introduced in Experiment 2. In addition to a button press used for the detection task, gaze behavior was assessed using an integrated eyetracking system. The analysis of saccadic reaction times in relation to the motor response showed that peripheral vision is naturally used to detect motion and form changes in MOT, because saccades to the target often occurred after target-change offset. Furthermore, for changes of comparable task difficulties, motion changes are detected better by peripheral vision than are form changes. These findings indicate that the capabilities of the visual system (e.g., visual acuity) affect change detection rates and that covert-attention processes may be affected by vision-related aspects such as spatial uncertainty. Moreover, we argue that a centroid-MOT strategy might reduce saccade-related costs and that eyetracking seems to be generally valuable to test the predictions derived from theories of MOT. Finally, we propose implications for testing covert attention in applied settings.