That was a foul! How viewing angles, viewing distances, and visualization methods influence football referees’ decision-making

Abstract

A football referee must choose the right position on the field in order to perceive a foul accurately. In previous research, decision-making for foul calls was compared across different situations within a match or even across different matches, which questions the comparability of decisions that often depend on the situational context. In this study, we experimentally controlled this situational context to investigate the effect of viewing distance and viewing angle on referees’ decision-making. We recreated real-life decision-making situations using markerless tracking devices and virtual reality (VR) animation processes to render first-person situations. We compared the decision-making accuracy of ten experienced football referees when judging situations from three different viewing angles and distances. Furthermore, we compared their decision-making accuracy in VR scenes with accuracy when viewing the same scenes from a bird’s eye and slow-motion perspective, i.e., with the perspectives used in official referee training. We found that decision accuracy is not affected by viewing angles and distances, but that the referee’s decision certainty is lower when viewing the foul situation from a greater distance. The visualization of the situations had an impact on the referee’s decision-making but only for detecting a simulation (i.e., a player acts like they have been fouled). Slow-motion scenes led to higher decision-making accuracy than VR scenes. Our study suggests a way to recreate VR situations for experimental studies, allowing researchers to control the context of each situation. Our findings help to disentangle the mixed findings of previous studies on distance and viewing angle effects on decision accuracies. Finally, we propose potential avenues to improve VR animation processes in future studies.