Many people interested in the origins of language have noticed the humanity’s peculiar sexual arrangements and wondered if they had anything to do with language’s start. What arrangement are those? Humans engage in a variety of heterosexual arrangements—polygamy, monogamy, polyandry—but we don’t organize our societies around systems in which males and females mate widely and randomly with each other (bonobos do that), nor do the males fight among themselves over who gets to mate with anyone and who does not (gorillas do that). To put it technically, adult human societies are organized in many ways but whatever way they choose they minimize competition between sperm. How could that have anything to do with language?
Well, Terrence Deacon has looked at the relation between sexual organization and the need for symbols to enable that organization. Chris Knight has investigated the impossibility of language under the standard ape society structure in which males contribute very little to survival. They fight among themselves and take what they want from the females. Until that system changed, Knight argues, language as a social tool was impossible. This blog has also insisted many times that the trust and sharing that language requires is only possible if the chief form of evolutionary selection was group selection rather than selection at the individual level.
At the technical level, all three of us have been saying that to have language you have to get rid of competition between sperm. So the breakthrough analysis of the Y chromosome’s genetic structure that has just appeared in Nature (introduction here ) is a real support to these ideas. It turns out that the human and chimpanzee Y chromosomes have diverged so much and so fast that it is as though we shared a last common ancestor from 310 million instead of 6 million years ago. What’s more, while chimpanzee sperm has been streamlining for ever tighter competition, the human Y chromosome looks to be competition free. This kind of finding is exactly the kind of thing that Deacon, Knight, and this blog have been looking for.