Image caption On a 50/50 chance, biology tends to favour choosing the right, the research suggests

Goalkeepers trying to stop penalty shots tend to dive to the right, research suggests - but only when their team is behind.

A study of penalty shoot-outs in World Cup matches from 1982 to 2010 showed keepers usually had an even chance of going left or right to defend the goal.

But the higher pressure of a losing position pushed them more to the right.

The study, to be published in Psychological Science, suggests humans' "right-oriented" brains are to blame.

They point out that many studies across the animal kingdom show a preference for the right in what would seem to be "50/50" situations, from dogs' tail wags to the side from which frogs strike their prey.

After studying the World Cup footage, the team, from the University of Amsterdam continued their study in the laboratory, asking participants to divide a line in half.

Those thinking about a positive goal, or put under time pressure, tended to split the line more toward the right - suggesting that goalkeepers slightly favour the right side as well.

"It's quite impressive. Even in this really important situation, people are still influenced by biological factors," said University of Amsterdam co-author Marieke Roskes.