In the intense mind game played between kicker and goalie in soccer's penalty shootout, there's some crucial information that kickers don't seem to be picking up on, and it could be costing them goals.
A team of researchers from University College London (UCL) examined all penalty shootout footage from World Cup and Euro finals matches held between 1976 and 2012.
They observed nothing unusual about play when the penalty kicks were made to random sides of the goal. In those situations, the goalies seemed to go with their gut, pick a side and defend it.
But whenever several consecutive penalty kicks went in the same direction, the goalies became less random in their own reactions and became more likely to dive in the opposite direction with the next penalty kick.
The researchers say the goalies are exhibiting the classic "gambler's fallacy": namely that something that is essentially always a 50-50 proposition will somehow have its odds changed by the recent past. For example, a coin toss -- heads or tails -- will, for every toss until the end of time, have the same odds: 50-50. But a gambler, putting emotion ahead of probability, might wager that if, say, 7 tosses in a row have been heads the next one is "due" to be tails.
Similarly, the goalies see a number of penalty kicks go in one direction, so they begin to think, "it HAS to go the other way this time."
But here's the rub, the researchers found: The kickers failed to notice.
"Because the goalkeeper displays the gambler's fallacy, kickers could predict which way the goalkeeper is likely to dive on the next kick," said lead author Erman Misirlisoy of the UCL Institute of Cognitive Neuroscience, in a press release.
"That would obviously give the kicker an advantage. They would simply aim for the opposite side of the goal. Surprisingly, though, we found that kickers failed to exploit this advantage."
Given any competition at an elite level -- be it soccer kicks, poker games or batter/pitcher duels in baseball -- edges gained on opponents through reliable information are hard to come by. A pitcher tipping his pitches will be hit hard; a poker player with a "tell" will be exploited; and a soccer goalie jumping in a predictable direction will be scored upon.
Why didn't the kickers exploit the fact that the goalies might move in a predictable direction? Senior author Patrick Haggard suggests it could be that the different penalty kickers, under tons of pressure, are not watching their teammates kicks closely.
"Each individual kicker may not pay enough attention to the sequence of preceding kicks to predict what the goalkeeper will do next," Haggard said.
It remains to be seen how the UCL team's findings will be used. "People can learn to predict. Perhaps football coaches could study the gambler's fallacy, and could train their penalty kickers in preparation for the next World Cup," suggested Misirlisoy.