Research reveals goalkeepers suffer 'gambler's fallacy' during shoot-outs
Goalkeepers in penalty shoot-outs are vulnerable to a psychological effect that has been the downfall of many a gambler, scientists have said.
After a string of penalties aimed in the same direction, keepers are more likely to dive to the opposite side of the net.
They display what psychologists call the "gambler's fallacy" - the mistaken belief that if an event is repeated unusually frequently over a set period it is likely to occur less often in the future.
The gambler's fallacy might tempt someone at a roulette table to place a big bet on black just because several reds had come up in a row.
Yet the odds of the ball landing on red or black are always even.
After studying 37 penalty shoot-outs that occurred in World Cup and UEFA Euro Cup matches over a period of 36 years, scientists concluded that goalkeepers do much the same thing.
They also found that kickers failed to exploit this weakness.
"Complete randomness is generally the best strategy in competitive games," lead author Erman Misirlisoy, from the Institute of Cognitive Neuroscience at University College London, said.
"Because the goalkeeper displays the gambler's fallacy, kickers could predict which way the goalkeeper is likely to dive on the next kick.
"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".
The researchers, whose findings appear in the journal Current Biology, point out that in high level soccer matches, goalkeepers cannot wait until the ball has been kicked to decide which way to dive.
Moments before the penalty is taken, they have to weigh up the odds of which way the ball is going to go.
Co-author Professor Patrick Haggard, who heads the UCL research group, said: "Cognitive fallacies can affect all of us, even if we are considered expert performers in a particular field,.
"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."