Judo players have no reason to feel blue

By Roger Highfield, Science Editor

The puzzling discovery that Olympic judo players wearing blue were more likely to be winners has at last been explained: their success was nothing to do with being blue – they were simply better athletes.

	The suggestion that wearing blue in judo is an advantage has been challenged

Various studies had already found that wearing the colour red seems to help people to win in boxing, wrestling and football, with scientists arguing that the colour influenced human aggression – reds and oranges also signal dominance and superiority throughout the natural world in birds sticklebacks and mandrills – and gave some advantage when human competitors are closely matched.

But this finding was challenged by the study of data from judo matches at the 2004 Olympics in the prestigious journal Nature which showed that athletes wearing a blue outfit win more often than those wearing a white outfit.

This seemed to suggest that blue is more intimidating than white. Or perhaps white is more noticeable, so that the blue contestant can better anticipate his opponent’s moves.

But today, in the Proceedings of the Royal Society, Biological Sciences, Dr Peter Dijkstra of the Universities of Groningen and Glasgow, and Paul Preenen, a student at the University of Amsterdam show the findings were flawed because the blue and white outfits – judogi – were not assigned at random.

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Top ranking athletes seeded in the competition to avoid playing each other in early rounds were given blue outfits in the first round but also had a higher chance of wearing blue in subsequent rounds.

They won frequently, of course, and that gave the win-bias for blue.

To make the bias worse, judo players in blue had, on average, several minutes more time to rest in a tournament.

Now, in their follow up study of 71 other judo tournaments, and a reanalysis of the 2004 Olympics data, where they took these confounding factors into account, they detected an equal number of blue and white winners, suggesting that a white-blue outfit pairing ensures fair play.

The team calls for a reanalysis of the data on the effects on colour to make sure that there are not confounding factors “to determine whether colour-associated winning biases exist in human combat sport in the first place.”

However, they say that the case for effects linked with red and with black, are in general supported by earlier work, so that it may be better for sporting authorities to avoid these colours and switch to blue and white pairings as a fairer alternative.

Several studies back the widespread perception — reinforced by scarlet tunics once used in combat, red power ties in the boardroom and golfer Tiger Woods’s red shirts — that the colour red enhances the power of those it adorns.

Anthropologists at the University of Durham found that football players score more goals – as supporters of Arsenal, Liverpool and Manchester United already know – and Olympic athletes win more matches when wearing red.

Redness also indicates anger, testosterone and male aggression in humans, mandrills and sticklebacks.

In experiments, red leg bands have helped ringed birds win a higher place in the pecking order.

“The evidence for red is comprehensible and may actually exist – several studies found these results,” says Mr Preenen.

Black is associated with evil and death in virtually all cultures. Two decades ago, a study found that teams of the National Football League and the National Hockey League with black uniforms were penalised more often, triggering debate about whether this might be due to referees being more prone to penalize athletes wearing black or an increased aggressiveness in players wearing black.