Expert perception and performance in offside decision making: An illusion escapes from the lab, runs on the field and is caught by a net

Abstract

In association football, the flash-lag effect appears a viable explanation for erroneous offside decision making. Due to this spatio-temporal illusion, assistant referees (ARs) perceive the player who receives the ball ahead of his real position. In a first experiment, we examined to what extent web-based offside decision-making training transfers to real-life offside situations. Ten ARs were exposed to a pre- and posttest and, in between, four off-field offside training sessions via a web-based training protocol. Eight ARs constituted the control group. During both pre- and posttests, an on- and off-field offside decision-making test was completed. First, an increase in response accuracy and a decrease in flag errors were observed for the training group from pre- to posttest in both test formats. Second, only the training group improved in recall and recognition accuracy of the attacker receiving the ball. Perceptual-cognitive skill training clearly results in a positive transfer to on-field performance.  In a follow-up experiment, a laboratory decision-making task was used to demonstrate that international ARs, compared to amateur players, do not have superior perceptual sensitivity. They modify their decision criterion according to the contextual needs and, therefore, show a higher response bias towards not responding to the stimulus, in particular in the most difficult situations. Thus, international ARs learn to compensate for their illusory perception, but also pay a specific cost (i.e., more misses), as a result of particular (cognitive) strategies. In summary, expert ARs differ from novices rather on the cognitive or decision-making level than on the perceptual level.