André Klostermann

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.

The quiet eye without a target: the primacy of visual information processing.

Motor-performance-enhancing effects of long final fixations before movement initiation-a phenomenon called quiet eye (QE)-have repeatedly been demonstrated. Drawing on the information-processing framework, it is assumed that the QE supports information processing revealed by the close link between QE duration and task demands concerning, in particular, response selection and movement parameterization. However, the question remains whether the suggested mechanism also holds for processes referring to stimulus identification. Thus, in a series of 2 experiments, performance in a targeting task was tested as a function of experimentally manipulated visual processing demands as well as experimentally manipulated QE durations. The results support the suggested link because a performance-enhancing QE effect was found under increased visual processing demands only: Whereas QE duration did not affect performance as long as positional information was preserved (Experiment 1), in the full versus no target visibility comparison, QE efficiency turned out to depend on information processing time as soon as the interval falls below a certain threshold (Experiment 2). Thus, the results rather contradict alternative, for example, posture-based explanations of QE effects and support the assumption that the crucial mechanism behind the QE phenomenon is rooted in the cognitive domain.

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.

Examining the response programming function of the Quiet Eye: Do tougher shots need a quieter eye?

Support for the proposition that the Quiet Eye (QE) duration reflects a period of response programming (including task parameterisation) has come from research showing that an increase in task difficulty is associated with increases in QE duration. Here, we build on previous research by manipulating three elements of task difficulty that correspond with different parameters of golf-putting performance; force production, impact quality and target line. Longer QE durations were found for more complex iterations of the task and furthermore, more sensitive analyses of the QE duration suggest that the early QE proportion (prior to movement initiation) is closely related to force production and impact quality. However, these increases in QE do not seem functional in terms of supporting improved performance. Further research is needed to explore QE’s relationship with performance under conditions of increased difficulty.

‘Success is in the eye of the beholder’: A special issue on the quiet eye

The visual system provides essential information for the control of movements enabling us to perform motor tasks with high levels of precision and accuracy. While there is a long tradition in perceptual psychology of studying separately the coupling of the perception and action that underpins motor skills performance (e.g. Heuer & Keele, 1996), only recently it has become evident that it is problematic to examine underlying perceptual processes that support action separately from the actions themselves, as the perceptual system constantly adapts to the specific demands of the task being performed (e.g. Dicks, Button, & Davids, 2010). Consequently, when studying perception–action coupling in the performance of complex motor skills, such as those that are required in the world of sport, it comes as no surprise that relatively little is known about the underlying mechanisms that support expertise. This special issue focuses on a phenomenon that has been extremely popular in the study of perception–action coupling – the quiet eye (QE). Vickers (1996) was the first to discover this perception– action variable, which has been shown to be closely related to proficient performance in a wide range of targeting, interceptive timing and tactical motor tasks (Vickers, 2007). The QE is characterised by the optimal temporal and spatial processing of visual information and is defined as the final visual fixation of a specific target or object in task space to be hit, caught or intercepted, before the initiation of the critical phase of a target-aimed motor response (modified from Vickers, 2007). Generally, it is found that the QE positively affects motor performance both intraand inter-individually such that experts when compared with near-experts and novices show earlier and longer QE periods. Likewise, the same pattern of result can be observed when comparing successful with non-successful trials (for recent reviews, e.g. Vickers, 2016). Vickers (1996) revealed in a basketball free-throw task that the QE of elite shooters was twice the duration of teammates who had lower percentages. Longer QE durations were also revealed for hits when compared to misses for the elite free-throw shooters. Furthermore, it has been consistently found that the QE promotes the learning and performance of a range of motor tasks (see Vine, Moore, & Wilson, 2014). In a typical study, Vine and Wilson (2010) showed increased learning rates for novices who were instructed to follow the five QE characteristics of elite golfers (e.g. Vickers, 2007) compared to novices who were trained with technical-training instructions only. The QE-trained group showed higher performance preservation in pressure tests highlighting the practical utility of this training for sports performance environments in which there are high levels of pressure and anxiety (see Vine, Moore, & Wilson, 2011). Furthermore, support for the QE’s positive effects on performance has been provided through examination of more than 28 different motor tasks (Vickers, 2016), and metaanalyses and recent reviews have identified the QE as a critical characteristic of perceptual–cognitive expertise (e.g. Rienhoff, Tirp, Strauß, Baker, & Schorer, 2016). Despite the large number of positive findings and successful replications that emphasise the phenomenon’s functionality in motor control and learning, it is surprising that few studies have examined the mechanisms that underpin the QE’s positive effects on performance, and as such little is known about possible mechanisms. There are, however, some noteworthy exceptions. First, Wilson, Vine and Wood (2009) equated the QE with the goal-directed and stimulus-driven attentional systems (Corbetta & Shulman, 2002) proposing an optimal attentional control explanation that particularly explains the QE’s functionality during the performance of motor

Perception-action coupling in complex game play: Exploring the quiet eye in contested basketball jump shots

ABSTRACT The duration of the final fixation before movement initiation – a gaze strategy labelled quiet eye – has been found to explain differences in motor expertise and performance in precision tasks. To date, research only addressed this phenomenon in situations without adversarial constraints. In the present study, we compared the quiet-eye behaviour of intermediately-skilled and highly-skilled basketball players in defended vs. undefended game situations. We predicted differences in quiet-eye duration as a function of skill and performance particularly resulting from late quiet-eye offsets. Results indicated performance-enhancing effects of long quiet-eye durations in the defended but not in the undefended game situation. Furthermore, in line with our prediction, later quiet-eye offsets were associated with superior performance elucidating the phenomenon’s relevance in online-demanding motor tasks. Further, earlier quiet-eye onsets were linked to successful performance supporting earlier suggestions that it is not only the duration but also the timing that matters. These findings not only extend the positive effects of the quiet eye in motor performance to dynamic game-play situations but also support the role of the quiet eye in response to programming and information processing respectively.

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.

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.

Picking an apple from a tree: Response-selection demands, inhibition requirements, and the functionality of the Quiet Eye in a far-aiming task

In the study of the mutual coupling between perception and action, the performance-enhancing effect of the last fixation before movement initiation, the Quiet Eye (QE), has been repeatedly shown. To the explanation of this phenomenon, among others, an inhibition hypothesis was formulated which suggests that the parametrisation of the optimal task solution is shielded against non-optimal task solutions. In this study, a prediction of this hypothesis was tested by manipulating response-selection demands over movement preparation in a targeting task which required to throw balls as accurate as possible at virtual target discs. Participants in the group with high response-selection demands always had to select one out of four targets, whereas the selection for the participants in the group with low response-selection demands was yoked to the selection of the other group. The results showed the predicted longer QE durations for the high response-selection demands group that, particularly, emanated from earlier QE onsets. Because of similar throwing demands, these differences cannot merely be explained by differences in the fine-tuning of the motor response but provide evidence for the suggested inhibition function. Particularly, with high response-selection demands, the parametrisation of the non-selected targets over movement preparation had to be inhibited. Descriptively, differences in the QE offset suggest that these shielding requirements persisted over movement control. This study extends earlier work on the theoretical foundation of the QE phenomenon and provides fruitful insights into its underlying mechanisms.

Gaze Strategies in Skateboard Trick Jumps: Spatiotemporal Constraints in Complex Locomotion.

Purpose: This study aimed to further the knowledge on gaze behavior in locomotion by studying gaze strategies in skateboard jumps of different difficulty that had to be performed either with or without an obstacle. Method: Nine experienced skateboarders performed “Ollie” and “Kickflip” jumps either over an obstacle or over a plane surface. The stable gaze at 5 different areas of interest was calculated regarding its relative duration as well as its temporal order. Results: During the approach phase, an interaction between area of interest and obstacle condition, F(3, 24) = 12.91, p < .05, ηp2 = .62, was found with longer stable-gaze locations at the takeoff area in attempts with an obstacle (p < .05, ηp2 = .47). In contrast, in attempts over a plane surface, longer stable-gaze locations at the skateboard were revealed (p < .05, ηp2 = .73). Regarding the trick difficulty factor, the skateboarders descriptively showed longer stable-gaze locations at the skateboard for the “Kickflip” than for the “Ollie” in the no-obstacle condition only (p>.05, d = 0.74). Finally, during the jump phase, neither obstacle condition nor trick difficulty affected gaze behavior differentially. Conclusions: This study underlines the functional adaptability of the visuomotor system to changing demands in highly dynamic situations. As a function of certain constraints, different gaze strategies were observed that can be considered as highly relevant for successfully performing skateboard jumps.