Just as the bewildering variety of human courtship rituals might all be considered forms of sexual selection, perhaps the world's languages, music, social and religious customs and even history are governed by universal features.

正如人类各种令人眼花缭乱的求爱仪式可能都被认为是性选择的形式，也许世界上的语言、音乐、社会和宗教习俗，甚至历史都受到普遍特征的制约。