Hey ref, do you need glasses?!
Authors:   , van Biemen Tammie 
Published: August 2024

Perceptual information is one of the key factors in the decision-making process of a referee, however knowledge regarding the behaviour of referees to gather this information from the environment is limited. The main aim of this thesis was therefore to understand how gaze behaviour contribute to expertise in football referee decision making, specifically examined in representative performance environments, or in other words: on the field instead of in a laboratory.
Referees adjudicate all sort of situations during a football match. First, I examined the judgment of specific game situations, to be specifically the assessment of (potential) foul situations and the anticipation on long passes. In foul situations, the results revealed expertise did seem to be underpinned by gaze behaviour, specifically a faster search behaviour by elite referees compared to sub-elite referees. Interestingly, when anticipating on long passes expertise was also found to be underpinned by gaze behaviour, however in these judgements elite referees expressed a slower search rate compared to sub-elite referees. Next, I examined how referees in general explore for perceptual information, by analysing their gaze behaviour while assessing open-play situations in situ. The results revealed referees use a gaze strategy that consists of a coordination between head and eye movements, as shown both by elite and sub-elite referees. Additionally, expertise did not seem to be underpinned by visual exploration behaviour, as no significant differences were found between the skill levels. The examination of gaze behaviour in different decision-making situations, revealed that the contribution of gaze behaviour to expertise in referee decision making can be understood in two ways. First, gaze behaviour is task-specific: expertise is underpinned by different characteristics depending on the specific situation to assess. In other words: elite referee performance is characterized by the ability to adapt gaze according to the situation. Second, expertise is underpinned by individual gaze strategies as well. By presenting individual data for each decision-making situation, the presence of individual variation was revealed. Referees showed individual preferences for example for a slow or fast search strategy. Expertise in gaze behaviour of football referees is thus not only dependent on task or situation, but also on individual style.
Most studies and training opportunities for referees rely on a simulation of the actual, on-field behaviour, for example by using videos. The strength of the studies in the current thesis, is that the examination of gaze behaviour was analysed in a representative performance environment, namely on the field, closely simulating actual performance behaviour. Thereafter, I tried to establish the degree to which this in-situ behaviour could be simulated using environments varying in representativeness. By comparing decision-making and gaze behaviour of referees both in-situ, in Virtual Reality (VR) and video-based, it was revealed the degree of representativeness has a significantly influence on the behaviour of referees. Performance environments with a high level of representativeness, such as a VR, result in reflective on-field behaviours, whereas environments with a low level of representativeness, such as video-based simulations, result in significantly deviant behaviours compared to on-field performance. It is therefore highly recommended to take into account the degree of representativeness when designing research and training.
Finally, the thesis provides some general recommendations for conducting research in in-situ environments. Furthermore, recommendations for practitioners in officiating are presented. Specifically, it was recommended to include measures of gaze behaviour in referee educational programs, talent development and identification. Additionally, investing in the application of VR was highly recommended. The representative environment can not only contribute to the skill acquisition of referees, but as well provide potential benefits for acquainting referees and creating awareness and respect for referee performances.