Gaze behaviour in offside decision-making in football: A field study

Gaze Behaviors, Estimated Quiet Eye Characteristics, and Decision Making of Nonexpert Assistant Referees Judging Offside Events in Soccer

The study analyzed the gaze behavior and decision-making performance of 20 soccer assistant referees while judging offside events. Specifically, gaze behaviors, gaze entropy, and estimated quiet eye (eQE; defined as the last fixation prior to the attacker's ball pass) characteristics (i.e., location, onset, offset, and duration) were analyzed in relation to decision-making accuracy. Although a significant number of fixations were observed on the offside line, the highest viewing time corresponded to the ball carrier. The gaze behavior indicated a high distribution of fixations, as evidenced by high stationary gaze entropy (>90%). The assistant referees also distinguished offside from onside positions above chance. However, they displayed nonprolonged eQE on the offside line. As a result, no significant relationships were found between the eQE characteristics and decision-making accuracy. The study concludes that the absence of more functional gaze behaviors, specifically with longer eQE focused on the offside line, impaired the decision-making accuracy of nonexpert assistant referees in soccer.

Perceptual-Cognitive Skills of Basketball Referees: On-The-Court Visual Search Behavior

Perceptual-cognitive skills are crucial in successfully managing information and decision-making in sports, particularly in high-pressure environments. We examined 16 basketball referees' on-the-court visual search behavior by comparing referees of different experience levels (experienced, n = 8; and novice, n = 8) and different court positions. Participants' visual search behavior was analyzed during 20 live gameplay situations using eye-tracking technology. Dependent variables were the number of eye fixations, mean fixation time, and total fixation time on selected areas of interest; and independent variables were the referees' experience and visual angles (lead and trail referee positions). Experienced referees exhibited significantly lower total fixation time than novice referees (p = .009). Referees in the trail position showed more fixations of shorter duration and a greater focus on the basket than those in the lead position. Our findings suggest that the visual search behavior of basketball referees varies with their court position and experience. These data provide valuable insights into referees' complex visual search patterns in the real-game context, and they highlight the importance of considering viewing angle and experience in future research.

How do referees visually explore? An in-situ examination of the referential head and eye movements of football referees

The majority of a football referee's time is spent assessing open-play situations, yet little is known about how referees search for information during this uninterrupted play. The aim of the current study was to examine the exploratory gaze behaviour of elite and sub-elite football referees in open-play game situations. Four elite (i.e. national) and eight sub-elite (i.e. regional) referees officiated an in-situ football match while wearing a mobile eye-tracker to assess their gaze behaviour. Both referential head and eye movements (i.e. moving gaze away from and then back to the ball) were measured. Results showed gaze behaviour was characterised overall by more referential head than eye movements (~75 vs 25%), which were of longer duration (~950 vs 460 ms). Moreover, elite referees employed faster referential movements (~640 vs 730 ms), spending less time with their gaze away from the ball (carrier) than the sub-elite referees. Crucially, both the referential head and eye movements were coordinated relative to key events in the match, in this case passes, showing that referees anticipate the passes to ensure that the referential movements did not occur during passes, rather before or after. The results further our understanding of the coordinative gaze behaviours that underpin expertise in officiating.

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.

"What needs to be seen": An exploration into the visual anticipation behaviour of different skill-level football referees while observing long passes on-field

It is well established that elite football referees possess superior anticipatory skills in specific game scenarios such as when assessing foul situations. Referees might also have better anticipatory skills in other important scenarios such as when observing a long pass. In these often-occurring situations, a referee has to use visual information to anticipate the outcome of the pass, in particular to foresee any potential infringements that might occur when players battle for ball possession. However, little is known about if and how football referees might anticipate outcomes in these scenarios. The aim of the current study was therefore to analyse the visual anticipatory behaviour of football referees when long passes occur during actual football matches. Elite (N = 4) and sub-elite referees (N = 12) officiated an actual football match while wearing a mobile eye-tracker to analyse their gaze behaviour when long passes occurred (N = 196). The results revealed differences in the way that the elite and sub-elite referees tracked the ball and anticipated the outcome of the ball trajectories. The elite referees used a lower search rate (1.3 vs 1.8 fix/s; p < .05) and were more likely to direct their gaze towards the ball during the moment of kick (77 vs 52%; p < .05) and the early flight-phase of the pass (68 vs 45%; p < .05), and subsequently produced earlier anticipatory eye movements to the player(s) receiving the ball (at 50% vs 60% of the ball flight; p < .05). This earlier anticipation may help the elite referees to better pick-up relevant information about the receivers that could be vital in making adjudications about any potential infringement when the ball does arrive. Referee education programs can use the current study to highlight the importance of visual search behaviour and help referees to adapt a strategy that is beneficial for long-pass situations.

Howzat! Expert umpires use a gaze anchor to overcome the processing demands of leg before wicket decisions

Cricket umpires are required to make high-pressure, match-changing decisions based on multiple complex information sources under severe temporal constraints. The aim of this study was to examine the decision-making and perceptual-cognitive differences between expert and novice cricket umpires when judging leg before wicket (LBW) decisions. Twelve expert umpires and 19 novice umpires were fitted with an eye-tracker before viewing video-based LBW appeals. Dependent variables were radial error (cm), number of fixations, average fixation duration (ms), final fixation duration (ms), and final fixation location (%). Expert umpires were significantly more accurate at adjudicating on all aspects of the LBW law, compared to the novice umpires (p < .05). The expert umpires' final fixation prior to ball-pad contact was directed significantly more towards the stumps (p < .05), whereas the novice umpires directed their final fixation significantly more towards a good length (p < .05). These data suggest that expert umpires utilize specialized perceptual-cognitive skills, consisting of a gaze anchor on the stumps in order to overcome the processing demands of the task. These data have implications for the training of current and aspiring umpires in order to enhance the accuracy of LBW decision-making across all levels of the cricketing pyramid.

Eye movements reflect expertise development in hybrid search

Domain-specific expertise changes the way people perceive, process, and remember information from that domain. This is often observed in visual domains involving skilled searches, such as athletics referees, or professional visual searchers (e.g., security and medical screeners). Although existing research has compared expert to novice performance in visual search, little work has directly documented how accumulating experiences change behavior. A longitudinal approach to studying visual search performance may permit a finer-grained understanding of experience-dependent changes in visual scanning, and the extent to which various cognitive processes are affected by experience. In this study, participants acquired experience by taking part in many experimental sessions over the course of an academic semester. Searchers looked for 20 categories of targets simultaneously (which appeared with unequal frequency), in displays with 0-3 targets present, while having their eye movements recorded. With experience, accuracy increased and response times decreased. Fixation probabilities and durations decreased with increasing experience, but saccade amplitudes and visual span increased. These findings suggest that the behavioral benefits endowed by expertise emerge from oculomotor behaviors that reflect enhanced reliance on memory to guide attention and the ability to process more of the visual field within individual fixations.

Gaze Behavior of Referees in Sport-A Review

The purpose of this review was to examine the literature on gaze behavior in referees. A literature search found only 12 relevant studies. Five of those studies were conducted on referees in association football (soccer), three on judges in gymnastics, one on softball umpires, and one each on referees in team handball, rugby, and ice hockey. Seven studies reported differences in gaze behavior between referees of a higher skill level and those of a lower skill level, while four studies found no differences. In addition, five studies reported differences between referees of different skill levels in both gaze behavior and performance, while four studies found differences in performance only. A number of methodological concerns arise from the current review. Among them are the lack of studies conducted in ecologically valid conditions, the lack of studies on peripheral vision, and the lack of data on referees who are working together as teams. Based on this review, we conclude that additional research is needed to clarify the relationships between gaze behavior and performance in refereeing. Practitioners who work with referees should be cautious when adopting gaze training strategies to improve selective attention, since the data on their effectiveness are scarce and sometimes contradictory.

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.