Christian Vater

Hand preference patterns in expert basketball players: interrelations between basketball-specific and everyday life behavior.

In the present study we examined the interrelation of everyday life handedness and hand preference in basketball, as an area of expertise that requires individuals being proficient with both their non-dominant and dominant hand. A secondary aim was to elucidate the link between basketball-specific practice, hand preference in basketball and everyday life handedness. Therefore, 176 expert basketball players self-reported their hand preference for activities of daily living and for basketball-specific behavior as well as details about their basketball-specific history via questionnaire. We found that compared to the general population the one-hand bias was significantly reduced for both everyday life and basketball-specific hand preference (i.e., a higher prevalence of mixed-handed individuals), and that both concepts were significantly related. Moreover, only preference scores for lay-up and dribbling skills were significantly related to measures of basketball-specific practice. Consequently, training-induced modulations of lateral preference seem to be very specific to only a few basketball-specific skills, and do not generalize to other skills within the domain of basketball nor do they extend into everyday life handedness. The results are discussed in terms of their relevance regarding theories of handedness and their practical implications for the sport of basketball.

Perceptual Training in Beach Volleyball Defence: Different Effects of Gaze-Path Cueing on Gaze and Decision-Making

For perceptual-cognitive skill training, a variety of intervention methods has been proposed, including the so-called “color-cueing method” which aims on superior gaze-path learning by applying visual markers. However, recent findings challenge this method, especially, with regards to its actual effects on gaze behavior. Consequently, after a preparatory study on the identification of appropriate visual cues for life-size displays, a perceptual-training experiment on decision-making in beach volleyball was conducted, contrasting two cueing interventions (functional vs. dysfunctional gaze path) with a conservative control condition (anticipation-related instructions). Gaze analyses revealed learning effects for the dysfunctional group only. Regarding decision-making, all groups showed enhanced performance with largest improvements for the control group followed by the functional and the dysfunctional group. Hence, the results confirm cueing effects on gaze behavior, but they also question its benefit for enhancing decision-making. However, before completely denying the method’s value, optimisations should be checked regarding, for instance, cueing-pattern characteristics and gaze-related feedback.

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.

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.

Tackling Quiet Eye issues on a functional level – comment on Vickers

Joan Vickers (2016) pinpoints the Quiet Eye ́s (QE) relation to superior learning and performance in numerous motor tasks. On this basis, this commentary emphasises that future research should particularly focus on underlying mechanisms to increase our understanding of the QE phenomenon. To this end, we suggest to pursue a functional approach that tackles the QE on a behavioural level by advancing theoretical as well as methodological aspects. Consequently, (a) an inhibition hypothesis will be outlined that supposes the QE to “shield” the parametrisation of the optimal task solution against alternative movement variants; (b) an algorithmic approach to the study of gaze behaviour will be introduced that maximises data quality and minimises manual analysis effort; and (c) a peripheral perspective on the QE will be depicted suggesting QE functionalities beyond foveal information processing.

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.

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.

How High-Level Athletes Use Peripheral Vision In Martial Arts

Given the high spatio-temporal demands in martial arts, anchoring gaze on so called “pivot points” may help to distribute attention to the periphery and to make use of the motion sensitivity of peripheral vision (Williams & Elliott, 1999). Therefore, it can be expected that gaze is anchored close to relevant attacking locations in martial arts. As these locations differ in Qwan Ki Do (QKD, attacks with arms and legs) and Tae Kwon Do (TKD, attacks mostly with legs), it was predicted that gaze is anchored higher at the opponent’s body in QKD than in TKD when attacks have to be defended in-situ. 10 QKD and 10 TKD experts (all male, 28 ± 5.8 years), all members of a national team, had to react in situ on 24 martial art specific attacks (2 sessions with 12 trials each) with 3 complexity levels (1, 2 or 3 techniques in a row) performed by another QKD or TKD expert. Eye movements were recorded with an EyeSeeCam (ESC). For the gaze analysis, a saccade detection algorithm was used to identify the anchoring height on the opponent’s main body axis after each saccade in 4 phases of the attack (Start, T1, T2, T3). The analysis of gaze anchoring height presented a significant main effect for the phase of the attack (p < .01, ηp² = .55), and an interaction between phase and martial art (p < .01, ηp² = .31). Post-hoc tests revealed that QKD athletes anchor gaze higher than TKD ath-letes immediately before the attack and during the first defensive movement (p < .05; d = 1.03). The results show that martial arts experts initially anchor their gaze higher, if attacks are expected from arms and legs (QKD) compared with attacks from legs only (TKD). One reason for this initially higher anchoring could be that attacks with arms can be executed faster than attacks with legs and that arms are often used to initiate an attack sequence which affords gaze to be close to these (higher) locations in QKD. Further, since the gaze vector moves down over longer attacking sequences, the visual pivot point might be dynamically adjusted. Thus, an anchoring strategy seems to facilitate the distribution of at-tention and to make optimal use of the motion sensitivity of peripheral vision. Future studies should aim at the identification of cost functions underlying the determination of an optimal pivot point.

Examining the functionality of peripheral vision: From fundamental understandings to applied sport science

In sports, it is important not only to locate gaze on the right location to utilize the high acuity of foveal vision, but also to attend to other objects in the environment without looking directly at them, accordingly, using peripheral vision. Peripheral vision becomes especially important if, for example, the processing of information from more than one location (e.g. players) is decisive in making accurate decisions. Since such decisions generally must be made under high spatio-temporal demands, costly eye-movements might be advantageously avoided by using peripheral vision for information pick-up from multiple cues. In a series of studies, we aimed to translate the demands found in sports and to investigate the functionality of peripheral vision in a well-controlled experimental paradigm, the multiple object tracking (MOT) task. MOT was implemented in a dual task, along with an additional event-detection task. The present article first presents an overview of sport-specific studies focusing on the functionality of peripheral vision and following, summarizes a series of three published MOT studies. These studies show that peripheral vision is used for simultaneous target monitoring and target-change detection and that visual and attentional demands affect gaze anchoring and change-detection rates. Results also reveal a dysfunctionality of saccades, and further suggest an event- and distance-optimized gaze-anchoring position. In the final portion of this article, we derive specific applications for future sports-specific research. Specifically, we suggest to: (a) use dual-task situations in sport-specific settings, such as monitoring multiple players in soccer and playing a pass at specific moments, (b) investigate the costs of saccades in sports situations with high spatio-temporal demands, as in martial arts, and finally, (c) manipulate attentional and visual demands. For each of these avenues of research, we sketch sports-specific experiments currently being conducted in our research group.

Anticipation of Beach Volleyball Attacks: A Comparison of Natural Versus Animated Virtual-Reality Scenes

The duration of the final fixation before movement initiation—a phenomenon labeled quiet eye (QE)—has been found to explain differences in motor expertise and performance of aiming tasks (Vickers, 2007). However, whether the same effect occurs in complex, on-field game situations remains unresolved. Consequently, this study examined intermediately (N 1⁄4 10) and highly skilled (N 1⁄4 7) basketball players’ QE behavior (onset, offset, and duration) as a function of performance (6 hits/ misses) in undefended free-throw and defended smallsided game situations (counterbalanced order). It was predicted that differences in QE duration (Vickers, 2007) and QE offset (de Oliviera, Oudejans, & Beek, 2008) would occur as a function of expertise and performance, not depending on game situation. The players’ actions were recorded with GoPro video cameras (25 Hz) and Applied Science Laboratories mobile eye-tracking systems (25 Hz) and were analyzed using mixed-factorial analyses of variance. Results revealed earlier QE onsets and longer QE durations in undefended versus defended situations (all p, .01). Independent of game situation performance, differences were found for QE offset, F(1, 15) 1⁄4 4.83, p, .05, hp2 1⁄4 .24, with later QE offsets for hits than for misses. Likewise, for QE duration, a main effect for performance, F(1, 15) 1⁄4 11.99, p , .01, hp2 1⁄4 .44, but also a significant Performance £ Expertise interaction, F (1, 15) 1⁄4 5.13, p , .05, hp2 1⁄4 .26, were revealed. Only the highly skilled players showed longer QE durations in hits versus misses ( p, .05). Finally, the 2 groups did not differ in their QE behavior (all p. .39). In summary, the study replicates positive QE effects for defended smallsided game situations but challenges the suggested mechanism in movement parametrization as the QE offset clearly exceeded movement execution. However, these findings might be explained in terms of attentional mechanisms. Anticipation of Beach Volleyball Attacks: A Comparison of Natural Versus Animated Virtual-Reality ScenesDefending beach-volleyball attacks requires good anticipation skills due to the highly time-constrained situations (Vansteenkiste et al., 2014). For examining the underlying mechanisms of these skills, using virtual reality is a promising approach because specific variations of players movements can be manipulated (e.g., the run-up of the attacker) to evaluate important cues for anticipating attacks. As a first step, animated virtual-reality scenes were created from natural beach-volleyball attacking sequences by manually animating players’ movements in Autodesk 3dsMax. Four conditions of attacking scenes were created: animated occluded, animated not occluced, natural occluced and natural not occluded. In occluded trials, videos were occluded 5 video frames (167ms) before ball-hand contact of the attacker. Participants were instructed to decide as accurate as possible (accuracy in %) in occluded trials and to respond as fast as possible (response time in ms) in non-occluded trials. 82 sport science students were tested in 120 trials with the same 30 mother-trials in each condition (counter-balanced order). Videos were back-projected on a large screen and participants responded using a 3-button-response system (WiiMote). After the study, participants evaluated the animated scenes with a questionnaire. Response accuracy was analysed with paired t-tests. Performance was lower for animated scenes compared with natural scenes (55.3% vs. 64.4%, t(81)=7.06, p < 0.01, d = 0.71) and participants responded later in animated compared with natural scenes (-170 ms vs. -237 ms before ball-hand contact, t(81)=7.46, p < 0.01, d = 0.32). Lower accuracies in animated scenes imply that visual cues were less helpful for anticipation. Questionnaire data revealed that the dynamics of a shot negatively affected anticipation in animated scenes and that rather late cues were used for decisions, which could explain the later responses. Future virtual-reality applications should especially focus on the animation of relevant visual cues and the dynamics of the attack.