Seeing Red

Red coloration is a known, testosterone-dependent signal of male quality in a variety of animals.  A statistical study of  ‘Association Football’ (Soccer) teams in England over a 55 year period showed that red teams had the best home record, with significant differences in percentage of maximum points achieved. The researchers, Russell Hill and Robert Barton, had  previously shown that in the 2004 summer Olympic games for four events (Boxing, Tae kwon do, Greco-Roman wrestling and Freestyle Wrestling) competitors randomly assigned a red uniform had a 55% win percentage.

Other studies found that referees scoring video bouts gave competitors higher scores when uniforms were digitally altered to be red.

Found at Der Spiegel.  Abstract of Soccer study.  Summary of Olympic study.