Researchers who study chimpanzees — looking to find out how human behavior arose — look for similarities and try to interpret them. The problem is that the very thing distinguishes human behavior is what we do not share with chimpanzees. Thus, it’s not clear how much light the chimps can really shed.

Recently, an Oxford team reported, “A new study suggests that the fundamental abilities underlying human language and technological culture may have evolved before humans and apes diverged millions of years ago.” In a way, that deepens the mystery. If the capacity for a human mind was present that long ago, why did no chimpanzee develop one?

Many human behaviours are more complex than those of other animals, involving the production of elaborate sequences (such as spoken language, or tool manufacturing). These sequences include the ability to organise behaviours by hierarchical chunks, and to understand relationships between distantly separated elements.

University of Oxford. “Chimpanzees perform the same complex behaviors that have brought humans success.” ScienceDaily, 5 December 2024.“ The paper is open access.

That is true but it misses the point entirely. Human language is not merely complex, like a termite mound. It is organized around abstractions. Human tools are not based only on substances like rocks but on abstract information about, say, the physics and chemistry of metals. Neanderthals, for example, apparently understood that if they buried smoldering wood, they could produce more resin for glue. It would be many millennia before someone could explain that burying the wood slows the burn by restricting the flow of the gas oxygen. But the Neanderthals caught on to the basic technique. So if these “fundamental abilities” were present before humans and chimps diverged (if they did), why did humans inherit them but not chimps?

Chimpanzees using tools

For example, even relatively simple human behaviours like making a cup of tea or coffee require carrying out a series of individual actions in the right order (e.g. boiling the kettle before pouring the water out). We break such tasks down into solvable chunks (e.g. boil the kettle, get the milk and teabag, etc), composed of individual actions (e.g. ‘grasp’, ‘pull’, ‘twist’, ‘pour’). Importantly, we can separate related actions by other chunks of behaviour (e.g. you might have to stop and clean up some spilt milk before you continue). It was unknown whether the ability to flexibly organize behaviours in this way is unique to humans, or also present in other primates. “The same complex behaviors”

It seems worth pointing out here that a great deal of human behavior — for example, making a cup of tea — is reflex action from long experience. It does not usually require complex thinking skills or problem-solving. Perhaps it would be surprising if chimpanzees could not do the same sort of thing in their own environment. They don’t, for example, develop electrical circuits for boiling water but they do need to crack nuts:

The study used data from a decades-long database of video footage depicting wild chimpanzees in the Bossou forest, Guinea, where chimps were recorded cracking hard-shelled nuts using a hammer and anvil stones. This is one of the most complex documented naturally-occurring tool use behaviours of any animal in the wild. The researchers recorded the sequences of actions chimps performed (e.g. grasp nut, pass through hands, place on anvil, etc.) — totalling around 8,260 actions for over 300 nuts.

Using state-of-the-art statistical models, they found that relationships emerged between chimpanzees’ sequential actions which matched those found in human behaviours. Half of adult chimpanzees appeared to associate actions that were much further along the sequence than expected if actions were simply being linked together one-by-one. This provides further evidence that chimpanzees plan action sequences, and then adjust their performance on the fly. “The same complex behaviors”

But surely that is in large part because, like humans, chimpanzees rely heavily on reflex actions while doing routine work. Not much planning is really required after a while. Of course, if a task is interrupted, cues are useful for getting back on track. But we are nowhere near understanding human language or tool use here.

Tool use and language

From the paper:

We discuss these results in light of possible interindividual variation in the systems of action organization used by chimpanzees during tool use, in addition to methodological considerations for applications of MI estimations to sequential behaviours. Moreover, we discuss our main findings alongside hypotheses for the coevolution of complex syntax in language and tool-action across hominin evolutionary history.

Howard-Spink E, Hayashi M, Matsuzawa T, Schofield D, Gruber T, Biro D. Nonadjacent dependencies and sequential structure of chimpanzee action during a natural tool-use task. PeerJ. 2024 Dec 5;12:e18484. doi: 10.7717/peerj.18484. PMID: 39650560; PMCID: PMC11625446.

It’s worth recalling that about 160 years ago, the Société de Linguistique de Paris refused to admit papers on the origin of human language. Paper like this one, while useful in their way, help us see why. Focusing on similarities to what chimpanzees do means avoiding the very factors that make human language unique — and those are the ones whose origin we wish to know.

Co-senior researcher Professor Dora Biro (University of Rochester) said: “There is increasing recognition that preserving cultural behaviours in wild animals — such as stone-tool use in West-African chimpanzees — should be incorporated into conservation efforts. Wild chimpanzees and their cultures are critically endangered, yet our work highlights how much we can yet learn from our closest relative about our own evolutionary history.” “The same complex behaviors”

But we actually haven’t learned anything about “our own evolutionary history.” From what we know the human mind — and human language as one of its products — has no history. The technology the mind produces has a history that we can trace, a history in which one technology builds on another. But as for the human mind itself, we see it when and where we see it. And where we don’t see it, nothing is a substitute.