WEDNESDAY, June 20, 2018 (HealthDay News) -- Anyone watching 2018 World Cup Soccer has to marvel at the referees' quick thinking. But slow-motion video playbacks may alter their ultimate decision, a new study suggests.
Researchers assessed 88 elite soccer referees' responses to videos of fouls. The refs handed out harsher penalties when they reviewed player fouls in slow motion.
There were no significant differences in the referees' judgment of whether or not a foul had occurred when they viewed either real-time videos (61 percent) or slow-motion videos (63 percent).
However, there were differences in their judgment of intention or force behind a foul. Refs were more likely to say a red card (dismissal from the field) was warranted when viewing slow-motion videos than real-time videos, according to the study.
"Our results suggest that slow motion can increase the severity of a judgment of intention, making the difference between perceiving an action as careless [no card], reckless [yellow card] or with excessive force [red card]," said corresponding author Jochim Spitz, of the University of Leuven in Belgium.
The findings were published in the journal Cognitive Research: Principles and Implications.
"The finding that referees were more likely to make more severe decisions following slow-motion replays is an important consideration for developing guidelines for the implementation of VAR [video assistant refereeing] in [soccer] leagues worldwide," Spitz said in a journal news release.
And the study is timely, given the debate on VAR's use in the FIFA World Cup, Spitz said.
The researchers concluded that slow-motion replays could help improve some calls -- such as off-side or determining the exact impact of a contact. However, it might not be the best way to make calls about player behavior and intention, they said.
"Slow-motion video may make it clearer who initiated a foul, whether there actually was contact and whether a foul occurred either inside or outside the penalty area," Spitz said.
"However, judging human emotion like intentionality is quite another story. It is also the reason why slow-motion footage cannot be used anymore in the courtroom as it increases the perceived intent," he said.
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