This story provides a classic warning for anyone trying to find psychological causes for things: the effect can just as easily be in the observers as in the thing we observe. Psychology students around the world are taught the story of Clever Hans, a horse that many believed could do arithmetic. Huge crowds would pay to see Hans, held by his trainer, being asked questions such as "what is five plus two", and answer by stamping his foreleg seven times.
This seemed like a wondrous example of animal intelligence, until a psychologist showed that Hans was performing his trick by reading the body language of his trainer. Hans would start tapping his foot. When he got to the correct number his trainer would relax, and Hans would read this signal and stop. What looked like a miraculous ability to do maths, was really a clever – but not miraculous – ability to act according to what his trainer did.
So there the matter rests – for the moment at least. Wearing red could give you an advantage in competitive sports, but it’s because of the effect it has on the observers, not the observed. And, just maybe, we'll try to be a bit more careful about calling victory as we watch contests happening in the London Olympics.