In soccer, penalty kicks are decisive events that can decide the outcome of a match. The average number of goals scored by both teams is typically low during regulation time in soccer matches (i.e., 2.5; Bar-Eli et al., 2007), and as a consequence, the scoring opportunity that is provided by a penalty kick can decide the outcome of a match. In addition, during a decisive penalty shoot-out, the importance to the outcome of the match is even more obvious.

In the penalty kick, the ball is placed 11 m from the goal area, which measures 24 ft (7.32 m) wide by 8 ft (2.44 m) high, giving the kicker a target area of 18 m² to aim at. Further to this, a kick is struck with a typical speed of 22–27 m/s, with the ball reaching the goal line in approximately 600 ms (Wood et al., 2015; van der Kamp et al., 2018). Due to constraints on the time that the goalkeeper requires to cover the entire goal area, the overwhelming advantage is in favor of the kicker (Wood and Wilson, 2010; Noël and Van der Kamp, 2012). It is therefore surprising that a large percentage of penalty kicks are not converted, with ~20–25% of the shots being missed or saved (Mcgarry and Franks, 2000; Jordet et al., 2007).

With this in mind, researchers have shown a significant interest in uncovering factors that effect accuracy and success in the penalty kick. Specifically, recent advances in mobile gaze registration systems have led to an increase in empirical studies that have attempted to explore gaze behavior and visual attention within the performance of the penalty kick (e.g., Wilson et al., 2009; Wood and Wilson, 2010, 2011; Piras and Vickers, 2011; Van der Kamp, 2011; Noël and Van der Kamp, 2012). Evidently, and similar to other far aiming tasks (e.g., Helsen et al., 2000; Rodrigues et al., 2002; Vickers and Williams, 2007; Land, 2009), these studies have demonstrated a functional coupling of gaze behavior and kicking, with the information made available from gaze fixations being pertinent in decision making, as well as maintaining effective performance (Behan and Wilson, 2008). That is, within the soccer penalty situation, the kicker has to deal with both a proximal and a distal target, i.e., the foot has to hit the ball (proximal target) as accurately as possible with an sufficient amount of force, and secondly, the kick has to accelerate the ball toward a target location within the goal that is outside of the goalkeeper's reach (distal target).

The kicker generally adopts one of two penalty kick strategies, which include to either attempt to anticipate the direction of the goalkeeper dive during the run-up to the ball and kick to the opposite side of the goal at the last moment (i.e., the keeper-dependent strategy); or, to use a more controlled approach and decide the direction of the kick without taking the goalkeeper's actions into account during the run-up phase of the kick (i.e., keeper-independent strategy) (Van der Kamp, 2006, see also Kuhn, 1988). The two penalty kick strategies have been shown to invoke distinct patterns of gaze, which are directly associated with the success of penalty kicks. For example, Noël and Van der Kamp (2012) showed that the distinct pattern of gaze in the case of the keeper independent strategy allowed for more optimal control of the kicking movements as compared to the gaze pattern elicited by the keeper dependent strategy. Gaze behavior within the goalkeeper independent strategy was associated with prolonged focus on the inside areas of the goal (distal target), shorter times fixating the goalkeeper, and longer fixation times toward the ball (proximal target), all of which resulted in kicks that were less centralized and gave the goalkeeper less opportunity to save the ball (Noël and Van der Kamp, 2012; see also Wilson et al., 2009; Van der Kamp, 2011; Wood et al., 2015; Kurz et al., 2018).

In the competitive environment, there are a number of distractors that can potentially influence typical gaze patterns of kickers. Such shifting in attention to task irrelevant cues has the potential to disrupt motor performance (Beilock and Carr, 2001; Wood and Wilson, 2010; Morris, 2012; Lidor et al., 2013). One of the more modern potential distractions to visual attention in soccer stadiums includes billboards that are used to advertise during competitive matches. These boards can typically be seen on the entire perimeter of the field, including being placed directly behind the goal area. These modern LED (light emitting diode) display boards allow for multiple advertisements to be scrolled across their screens for the duration of a match. Advertisements appear and re-appear in differing formats and typically also include images that move from left to right, or right to left in direction. It is clear that a moving advertisement behind the goal has the potential to catch visual attention during a penalty task and thus to disrupt the typical gaze patterns of the kicker, with potential performance implications.

These performance implications can be two-fold. First, the attentional shift could have a non-specific effect on performance, in which the mere presence of the advertisement and/or the motion of the advertisement would result in a generic disruption of kicking performance measures including increased inaccuracy and/or precision in aiming. In other words, the (moving) advertisement may function as a distractor (e.g., Beilock and Carr, 2001). On the other hand, the attentional shift could have a specific effect on performance, that is, influencing kicking accuracy in a systematic manner depending on the direction of the moving advertisement. This would be analogous to the Duncker illusion (Duncker, 1929). Duncker (1929) demonstrated that background motion can induce an illusory perception of motion of a stationary foreground object. This illusory perceived motion of the object is in the direction opposite to that of the background motion (Zivotofsky, 2004). Most critically, it has been shown that such background motion can have similar effects on action, particularly within aiming tasks. Brouwer et al. (2003; see also Soechting et al., 2001) reported that background motion from left to right and right to left resulted in systematic aiming errors to the left and right of the target, respectively. This is in line with later findings that far aiming tasks are impacted by allocentric or contextual information (Van der Kamp and Masters, 2008; Van der Kamp et al., 2009; Shim et al., 2014).

The present study examines the effects of a stationary and moving advertisement behind the goal area on penalty kick performance. To this end, we investigated the gaze behavior and kicking performance of intermediate skilled soccer players taking penalty kicks in three differing advertisement conditions, namely no advertisement, a stationary advertisement, and a moving advertisement. The later condition consisted of an advertisement moving from left to right and an advertisement moving from right to left. Participants were enticed to use a keeper-dependent strategy and give themselves the best opportunity to score a goal by taking the goalkeepers dive into consideration when deciding in which direction to kick the ball¹. We were interested to see whether the moving advertisement did in fact catch the kicker's attention and affect gaze behavior, and if so, whether this would disrupt subsequent penalty kick performance. We hypothesized that if the advertisement would serve as a distractor, then the disruption, if any, would be non-specific that is, it would result in an overall decrease in kicking performance measures (e.g., aiming location and/or precision). Alternatively, if the moving background would have specific effects, then systematic changes in kicking performance measures (e.g., aiming location) would be dependent on the direction of motion of the advertisement.

Initial analysis of the Mobile-Eye data revealed that of the 16 participants, we were unable to analyse the gaze behavior of four of the participants due to issues with their video clarity. Therefore, 12 participants (all male, and right footed) were used in the final data analysis, totalling a possible number of 576 penalty kicks to be analyzed. However, a total of 564 penalty kicks were analyzed due to problems with the digital camera not having recorded every possible kick for each of the participants. To test the assumption of data normality, the Shapiro-Wilks W-tests were conducted on all dependent variables. In the cases that the assumption of normality was violated, Friedman and Wilcoxon Signed-Rank tests substituted parametric ANOVA'S and t-tests, with Dunn-Bonferonni corrections used where appropriate.

With the introduction of LED billboards within competitive sport that allow moving advertisements to be displayed around soccer stadiums during game time, there is a need to understand its potential effects on visual attention. Specifically, these billboards are placed around the field, including the area behind the soccer goal area, with the potential to distract the visual attention of a player during a penalty kick, a critically decisive event within competitive soccer. It is important to understand this as previous research has demonstrated a functional coupling of gaze behavior and kicking, with the information made available from gaze fixations being pertinent in decision making, as well as maintaining effective performance (Behan and Wilson, 2008). Further to this, studies have shown the effect of distractions to visual attention, with shifts in attention to task irrelevant cues having the potential to disrupt motor performance within far-aiming tasks like the penalty kick (Beilock and Carr, 2001; Wood and Wilson, 2010; Morris, 2012; Lidor et al., 2013). We therefore investigated whether a moving advertisement positioned behind the goal area did in fact catch the visual attention of participants performing the penalty kick, and, whether this has any effects on subsequent motor performance. We hypothesized two possible effects of the moving advertisement. First, a moving background can function as a distractor, resulting in a non-specific disruption of penalty performance measures, especially in terms of aiming accuracy and precision. Alternatively, a moving background may affect the perception of target location, inducing systematic changes in penalty performance and aiming which would be specific for the direction of motion of the advertisement, analogous to the effects of the Dunker illusion observed for aiming task (e.g., Soechting et al., 2001).

It is worth noting from the initial perusal of the gaze behavior results that participants indeed used a goalkeeper dependent strategy during the experiment, with an average 78% of gaze spent looking at the goalkeeper, which was expected given the nature of the instructions to participants. The key significant finding in the gaze behavior data however was that the moving advertisement indeed caught the attention of participants compared to the no- and stationary advertisement conditions. Although gaze was affected by the motion of the background, no significant differences between the penalty performance outcome measures, namely success, miss and save rates, were found between the three conditions. Also, the participants did not significantly differ in the ability to decide and kick the ball to the opposite side of the goalkeeper dive, or differ in the accuracy of ball placement (i.e., absolute distance from the goal's center) between conditions. In fact, the only significant difference observed was with respect to the precision of ball placement (i.e., variable distance), suggesting less precise kicks in the moving advertisement condition compared to the no advertisement condition. This might suggest a small non-specific distractive effect; however, we note that the variable measure for the stationary condition was numerically (but not statistically) even higher, suggesting that the disruptive effect, if any, is not induced by the motion of the advertisement.

When comparing gaze behavior between the moving advertisement conditions, we found that participants' visual attention shifted in more trials to the advertisement when it moved from left to right compared to when moving right to left. Presumably, this also lead participants, on average, to spend more time viewing the advertisement when it moved from left to right. In relation to this finding, it has been found that when looking at pictures of natural scenes, neurologically intact individuals show a leftward bias in the direction of their first eye movement. The presence of this leftward bias within spatial attention is known as pseudoneglect (Nuthmann and Matthias, 2014; Hartmann et al., 2019; see Nicholls et al., 2010; Noël et al., 2015 for pseudoneglect in kicking tasks). This as well as the fact that the angle of the run up for the right footed players place the advertisement in the corner of the eye, could be the reason why the participants were more likely to look to the advertisement within the left to right condition. We did only include right-footed players within the present study. Future research should consider whether similar findings occur within left-footed players due to the differing constraints on the run-up for these players, and also because some authors have argued that pseudoneglect effects may be lateralized (McCourt and Garlinghouse, 2000).

Although visual attention differed, we found no measurable difference in the penalty performance outcome measures between the two moving advertisement conditions. Yet, when aiming is concerned, a significant effect on the ball landing location was found: kicks were aimed to the left of the center of the goal when the advertisement moved from the left to right, while kicks were placed to the right of the center of the goal when the advertisement moved in the opposite direction. This theoretically pertinent result is aligned with previous findings in pointing and hitting using the Duncker illusion (Soechting et al., 2001; Brouwer et al., 2003), in which the presence of background motion from left to right and right to left resulted in systematic aiming errors to the left and right of a target, respectively. Taking this as well as later findings that accuracy of far aiming tasks is impacted by allocentric or contextual information (Van der Kamp and Masters, 2008; Van der Kamp et al., 2009; Shim et al., 2014), our results suggest the exploitation of allocentric information sources in far-aiming task like the penalty kicks. Initially, this would seem in contradiction to the two visual systems model proposed by Milner and Goodale (2008), as the control of action typically exploits egocentric information. Yet, as Van der Kamp and Masters (2008), Van der Kamp et al. (2009), Shim et al. (2014) have suggested, aiming tasks such as the penalty kick may involve identifying landing location and this process may actually be more consciously controlled and thus involve the ventral stream, thereby exploiting allocentric information (see also Willingham, 1998). To what degree, the, presumably unintended, systematic effects on aiming accuracy can actually also bring about a degradation in performance outcome with a real goalkeeper trying to save the penalty kick must be addressed in future studies. That is, in the present study, the exact aiming location did not affect the performance outcome scores, but when using a real goalkeeper, differences in aiming can potentially bring the ball (just) within reach, affecting the opportunities for the goalkeeper to intercept the ball.

A few additional notes have to be made regarding the findings that relate to representativeness of the current experimental procedures. With our current design, the situation enforced a keeper-dependent strategy which has allowed us to maximize the penalty takers visual attention to the goalkeeper and the goal area. However, it is important seek to which degree these findings can be generalized to kickers who use a goalkeeper-independent strategy. Due to the differences in visual gaze patterns across the two penalty taking strategies, it is pertinent to understand the effects on visual attention and subsequent penalty performance within the goalkeeper-independent strategy as well. A likely difference is toward the timing of the effect. While with the current keeper-dependent strategy, a moving advertisement can affect aiming almost through the entire run-up and kick, it is likely that with a goalkeeper-independent strategy the effect is restricted to the preparation and early phase of the run-up, because within the keeper-independent strategy, kickers tend to focus their attention earlier and longer toward the ball. Also, the length of the run-up is a potential factor influencing the relative amount of time kickers spend looking at the goalkeeper, goal and ball, and thus, their susceptibility to a moving advertisement (Kurz et al., 2018). Another concern might be that in the competitive environment, kickers only have one attempt to complete a penalty kick and previous research has suggested that participants tend to adjust penalty strategies as the trials continue in order to be more successful (Wood and Wilson, 2010), and in the current study also may have adapted to the attention drawing effect of the moving advertisement, having less effect over time. It would be interesting to see the effects of a moving advertisement in a single attempt in future studies in order to better mimic the competitive situation. We do think, however, that with respect to the information available for aiming and the spatial constraints on action our design is reasonably representative relative to on-field or competitive situations. In fact, the major flaw in terms of representative design is in the absence of dynamic interactions between kicker and goalkeeper. This relates to kicker being instructed to use a keeper-dependent strategy (as discusses above) and the use of a goalkeeper projection, which -obviously- did not respond to the kickers' action. Importantly, therefore, future research must verify the observed effects of moving advertisement in on-field environments, for instance, by analyzing video-footage of competitions. A final but relevant concern would be the difference between the pressure perceived by the participants during the current study, vs. the pressure experienced in a competitive environment. Attentional control theory (ACT) propose that anxious individuals both orient more rapidly to salient or conspicuous stimuli, and disengage from them more slowly (Wilson et al., 2009). This is theoretically interesting as implications are that in higher anxiety competitive situations, a moving advertisement could affect attention even more that in the penalty kickers shown within this study. Future research, including notational analysis of video-footage, should take this into consideration.

In conclusion, a moving advertisement placed behind the goal area was found to catch the visual attention of soccer penalty kickers using a goalkeeper-dependent strategy, with no measurable distractive non-specific effects on penalty kick performance measures. However, importantly, systematic effects on aiming were found when comparing conditions in which the advertisement moved in opposite directions suggesting that the aiming accuracy of the penalty kick is impacted by task-irrelevant contextual information.

The datasets generated for this study are available on request to the corresponding author.

The studies involving human participants were reviewed and approved by Scientific and Ethical Review Committee, Faculty Committees, Faculty of Behavioral and Movement Sciences. The patients/participants provided their written informed consent to participate in this study.

Article was planned by GP, JK, and GS. Data was collected by GP. Data analyzed by GP and JK. Article write up by GP, assisted by JK, and final sign off by GS.