Science Advances has published a brief report by W. Tecumseh Fitch, Bart de Boer and others whose finding is summed up in the title, “Monkey vocal tracts are speech-ready.” The authors investigated the sounds made by monkeys and concluded that they show enough variation to permit a decent vocabulary. Thus, it cannot have been changes in the vocal tract that got speech rolling.
I am reporting these results because of my respect for both Fitch and de Boer, and because the New York Times picked up the story and had it covered by my longtime friend Carl Zimmer. But truthfully I cannot see why the Times bothered. I suppose the reed instruments of Hayden’s day were “jazz-ready,” yet nobody played Benny Goodman. It is so uncontroversial as to be banal to say that it takes more than a vocal tract to produce speech.
First, primates had to get voluntary control of their vocalizations. Chimpanzees have voluntary control of their hands and, thus, can be taught the rudiments of sign language. They seem to have almost no voluntary control of their vocalizations and despite extensive training efforts do not learn to say words.
Next, our vocal tracts do differ from those of apes and we have much more precise control of our tongue and lips. Presumably, these refinements came after our lineage began talking. They are part of the story of how the lineage changed once language had begun, not part of the origins tale itself.
Third, even though chimpanzees, bonobos, and gorillas are all able to learn some signs, none of them sign in the wild. Those who have been trained to sign still do not converse among themselves. They are smart enough to understand some words, yet they do not bother with language.
The explanation for language’s rise, therefore, must be something other than a lack of sufficient vocal or intellectual ability. On this blog I have argued frequently that language serves a co-operative function not required of other primates. Apes can occasionally cooperate and they lead very social lives, but their societies are not organized in a way that demands cooperation from other members of the community. For apes, the odd cooperative moment is nice to have but not required. Humans, on the other hand, are such an interdependent species that life without cooperation is guaranteed to be nastier, more brutish, and shorter than an ape’s.
By the way, a commenter named Yair Shimron recently complained on this blog that cooperation and trust was not the original feature of language. He stated, “the developers of language had in minds and in mouths no more than emotional sounds, and they were evolving them very slowly step by step to become words founded on phonetics.” I suppose this means that language began as an emotional expression and words came later. Perhaps Yair and I disagree simply on when vocalizations became language. Babies at eight months are babbling. Can we say they are talking? Usually, we wait for words before we say that, but human babies babble and baby chimpanzees do not. In my book version of Babel’s Dawn, I describe a very long period (million plus years) of babbling ancestors who did not speak words. So perhaps Yair and I are not as far apart as it might seem.
Yair maintains his own blog Language Evolution—Absolutely New Way of Thinking. I am not on his wavelength, but it is worth a peek.