之前就有 paper 說在人類，程度接近的隊伍，穿紅的比較容易贏球。Hill, R. and Barton, R. Nature, 435, 293 (2005)
作者試著繁殖，紅頭或黑頭的雀鳥 (雀鳥在成年之前都是灰頭的，成年之後頭才會有紅色或黑色)，有些組爸媽的顏色跟小朋友不一樣，有些組是一樣的，有些比較大隻、有些比較小隻，在成長過程讓小朋友們知道他們打架打贏的情況是跟頭的顏色沒關係 (就還是跟體型比較有關係)。所以啦，他們的成長過程並沒有恐嚇他們紅色比較容易贏，他們知道打不打得贏跟頭的顏色沒關係，也沒有爸媽一定是什麼顏色的影響。
而且小鳥看到 紅頭的對手就會開始緊張... (他們去測荷爾蒙)。
Is red an innate or learned signal of aggression and intimidation?
Sarah R. Pryke
Department of Brain, Behaviour and Evolution, Macquarie University, Australia
Red coloration has been associated with dominance and aggression in a number of animals. However, it is unclear whether the increased aggression of red individuals or the avoidance of red opponents is an intrinsic or learnt response. By experimentally controlling for genetic and environmental effects, I tested for innate competitive differences and red-enhanced contest success in sexually immature (uncoloured) red and black head colour morphs of the Gouldian finch, Erythrura gouldiae. Despite juveniles being reared by foster parents of the same and different colour morphs, there were no differences in competitive abilities between uncoloured red and black males. However, when I experimentally added a red head mask to uncoloured males, red (but not black and novel blue coloration) was associated with winning contests, irrespective of an individual's underlying genetics or postindependence social experience. In addition, uncoloured opponents expressed higher stress responses (corticosterone) and avoided conflicts with red-painted competitors. The association between red coloration and aggression may be an innate response to aid facultative fight or submissive decisions, and adds to growing evidence suggesting that red coloration may be a general signal of intimidation.