THE UPSIDE DOWNHomo Loquens – Why We Learned to Talk

It’s not hard to see how the evolution of cooperation and the evolution of language are mutually reinforcing, writes John Mitchinson

In 1973, the German animal behaviourist Karl von Frisch was jointly awarded the Nobel Prize for his work on the language of honeybees. He had decoded the complex sequence of movements called the ‘waggle dance’ by which bees tell one another the quality, distance and precise location of a food source. To date, it remains the only widely accepted example of we humans penetrating the mystery of another species’ language.

Communication systems, intelligence, emotions, problem-solving, even creative play, are all things we share with other species – but talking is our superpower. Why did we evolve the capacity to speak at all, when no other species appears to – or at least not to the same degree? 

It seems overwhelmingly likely that a complex behaviour like language evolved gradually.  Although our closest relatives, chimpanzees and bonobos, have never learned to talk, we know they can understand a certain amount of our language, use symbols, possess a sense of time and can conceive of other chimps as thinking creatures. They aren’t as good as us at doing any of these things but, the more we study them, the more the differences seem to be quantitative rather than qualitative. 

Given that we both evolved from a common ancestor that didn’t talk, what was it that set us on the path to loquaciousness?

The answer may well be connected to the relative length of human childhood. 

We are born completely helpless: our brains only reach full size at the age of six, and our bodies take another decade to catch up. A chimp’s development is more rapid. They are born with an almost full-sized brain and stay close to their mothers for a decade. Significantly, the mother chimp dedicates all the first five years to looking after her offspring on her own – during that time she won’t reproduce again. Humans, of course, can and do reproduce much more frequently, despite the longer development period of their children.

One of the more persuasive solutions offered to this apparent paradox is that we have evolved to be helpful. The work of the American primatologist Sarah Blaffer Hrdy suggests that one critical manifestation of this helpfulness is the sharing of responsibility for the parenting of children, with a network of relatives including fathers, siblings and grandparents on hand to help as well as other non-genetically connected helpers, like nannies and midwives. 

This theory, known as the cooperative breeding hypothesis, might also explain why human brains have been able to increase in size relative to our primate cousins. Big brains mean big heads and big heads mean difficult births. A woman’s chances of survival when giving birth to a large-brained human child are greatly increased by the presence of a helpful relative or midwife. A chimp can give birth easily on her own.

A network based on help, trust and negotiation would tend to select for a better form of communication so it’s not hard to see how the evolution of cooperation and the evolution of language are mutually reinforcing. Longer childhoods gave us more time to learn, and language became the medium for that learning. And although it’s impossible to be precise about when this positive spiral first begins to turn – language, like brain tissue, doesn’t leave a trace in the fossil record – there does seem a good chance that something resembling a language predates Homo sapiens. 

In his 2021 book, The Dawn of Language, the Swedish linguist Sverker Johansson favours Homo erectus, who enjoyed a stable culture for more than a million years. The doubling in brain size over that time, he believes, was probably the result of an interaction between the evolution of cooperation and the development of a protolanguage. If that is the case, then Neanderthals almost certainly had a form of language too – which no doubt helped facilitate the regular inter-species liaisons we now know to have taken place with the Homo sapiens arrivistes from Africa.

However long it took, and whatever evolutionary trade-offs it required, the brain of a new-born human is the most miraculous thing. It has more neural pathways and can make more potential connections than the adult brain. It is tuned to learn from the world around it like nothing else in nature in a constant to-and-fro of stimulus and response. 

In The Philosophical Baby (2010), the American developmental psychologist Alison Gopnik suggests that it is through this give-and-take of early play that language emerges: “Children aren’t wild pretenders because they are consciously trying to learn about the world or other people. They are wild pretenders because they are children and that’s what children do. It’s only from the broader evolutionary perspective that their uninhibited useless pretence turns out to be among the most deeply functional human activities.”

Honeybees might dance, but as soon as we can, we talk.

John Mitchinson is a writer and publisher and co-founder of Unbound, the world’s leading crowdfunding platform for books. He was one of the founders of BBC’s ‘QI’

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