There is a predictable pattern among goalkeepers when they are pitted against multiple kickers in a tense penalty shootout, which is exploitable. After kickers repeatedly kick in one direction, goalkeepers become increasingly likely to dive in the opposite direction, according to an analysis of all 361 kicks from the 37 penalty shootouts that occurred in World Cup and UEFA Euro Cup matches over a 36-year period.
The findings reported in the Cell Press journal Current Biology
on July 31 highlight the importance of monitoring and predicting sequential behavior in real-world competition, according to the researchers, a lesson that could be applied to many areas of life.
"Cognitive fallacies can affect all of us, even if we are considered expert performers in a particular field," says Patrick Haggard of the University College London. "It is important to try to be aware of situations in which we may be vulnerable to bad decision making. Then we may be able to avoid making mistakes."
For example, Haggard and Erman Misirlisoy say, at a casino roulette table it's not a good idea to place a big bet on black simply because there have been several reds in a row. Previous events aside, red and black are always equally likely. The natural tendency to suspect otherwise is known as "gambler's fallacy."
Haggard and Misirlisoy are generally interested in how people make decisions, and they recognized soccer and other sports as great examples of competitive cognitive strategies at work.
"In a penalty shootout, a goalkeeper and a group of kickers do their best to outwit each other," Misirlisoy says. "How they control their behavior gives an insight into cognitive strategies more generally. Just as a kicker and a goalkeeper need to decide between kicking left or right and diving left or right, we often find ourselves in life making decisions between two roughly balanced options, such as two alternative routes to where we want to go."
As is often the case in sports, goalkeepers can't wait until the ball has been kicked to dive or they'll miss it every time. They simply have to guess. The best strategy for both goalkeepers and kickers is to behave unpredictably, diving and kicking in random directions.
The researchers' analysis of penalty shootouts shows that even the very best goalkeepers in the world suffer from a cognitive fallacy in selecting which way to dive next, making their next move more predictable than it really should be. Fortunately for those goalkeepers, kickers failed to exploit those goalkeeper biases, the researchers found.
What's a goalkeeper to do? Misirlisoy suggests that it might be good strategy to decide on a random sequence of dives before the game and follow that sequence regardless of what kickers do. Until that day comes, kickers could learn to predict which way goalkeepers might dive.
For the researchers, the work left them experiencing this year's World Cup series in a whole new way. "We found we were thinking about behavioral decision making as much as about the entertainment," Misirlisoy says. "We were trying to predict which way the goalkeeper would dive, and we didn't pay much attention to how many times the ball ended up in the net."