Influence of players' vocalisations on soccer referees' decisions.

The influence of a potentially fouled player's vocalisations on the referee's decisions was investigated. Experienced soccer referees watched video clips of real-match situations that were presented either without sound or with sound where a player's vocalisations were clearly audible and made judgements regarding fouls, direction of play and personal penalties. The results revealed that players' vocalisations had no impact on the foul decisions of the referees. However, once a referee made a foul decision, the player's vocalisations led to an increased number of personal penalties (increase in yellow cards) for the foul-causing player. In addition to crowd noise, a player's vocalisations during a foul are used as a proximal cue in the referee's decision-making process.