Exogamy, Rites of Passage and Human Self-Domestication

Early scholars such as Darwin noted that a series of similar trait changes occurred between domesticated mammals and their wild counterparts, and that similar trait changes occurred in humans. Follow-up studies in recent years have further confirmed the findings of earlier scholars. These changes are known as domestication syndrome (DS). Human DS variation occurred over thecourse of two to three hundred thousand years before and after the formation of Homo sapiens, and is thought to be the result of human self-domestication. The main way to realize human self-domestication has been an important topic in recent years. And more than theoretical explanations have been proposed. In this paper, the main methods of previous research are briefly reviewed, and some related concepts are slightly revised. For example, the attributes and efficacy of selective reproduction in silver fox domestication experiments, the approximate correspondence between DS and the reduction of sexual dimorphism, and the correlation between DS causes and sexual selection.On this basis, this paper proposes a preliminary judgment on the causes of human DS that is different from the past : according to our present knowledge (empirical facts), there are two powerful drivers of DS variation, namely,exogamy and coming-of-age ceremony in tribal institutions. These two systems existed completely before the colonization of Australian tribes. This paper usesthe early classical ethnography of Australia by Fison, Howitt, Spencer, and Gillen to analyze and summarize the basic content of these two systems (reconstructing the original state of the system before colonization). Then, its domestication function and efficacy are discussed. Based on this, it is concluded that the joint effect of exogamy and coming-of-age ceremony is the main way for human beings to achieve self-domestication. We are very fortunate to have evidence about the Australian tribes in the early stages of civilization before colonization. We can trace their origins and examine their evolution accordingly. The alliance of two multimale-multifemale（mm-mf） groups through non-violent approach is the first step in the speciation of Homo sapiens.The tribal system formed in this historical link is the initial process of human civilization and an important foundation for human prosperity to this day.