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Did invention make us human?

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Did invention make us human? 46

 

In one of Aesop’s fables, The Crow and the Pitcher, we are introduced to a thirsty bird. As luck would have it, the bird happens to stumble across a pitcher, which has a pool of water at the bottom. Despite all his desperate attempts, however, the narrowness of the pitcher and the size of his beak means he cannot get at the precious water. In his anguish, an idea strikes him. One by one, he drops pebbles into the pitcher, until the water level has risen enough for him to drink it.

Aesop was trying to make a point about the value of perseverance, but lab studies on Eurasian jays, New Caledonian crows and rooks seem to show that corvids really are capable of understanding that dropping stones in a container will make its water levels rise. This fable, and the experiments it inspired, are critical evidence that corvids understand cause and effect – something called causal reasoning.

In his new book The Pattern-Seekers: A New Theory of Human Invention, Simon Baron-Cohen, professor of psychology and psychiatry and director of the Autism Research Centre at Cambridge University, thinks that crediting corvids with causal reasoning is a step too far. Instead, he argues that the birds are simply associating a behaviour with a particular result. They drop stones, so they get a tasty piece of meat that has floated to the top of a tube, but they don’t really understand why the two things are linked. The birds are clever, there’s no doubt about that, but it isn’t proof that they’re capable of inventing a tool.

Invention, Baron-Cohen contends, is something that only humans are capable of. But it’s not just uniquely human, it’s also the very thing that sets us apart from animals and has turned our species into the “scientific and technological masters of our planet, eclipsing all other species”. Invention, in other words, is what makes us human.

To put a date on this cognitive leap, Baron-Cohen postulates that between 70,000 and 100,000 years ago a genetic change took hold in the human brain that enabled what he calls a ‘systemising mechanism’ to evolve – a new circuit that causes humans to look for and invents new systems or patterns through causal reasoning, which he refers to as if-and-then logic. “You’re taking some input – that’s the ‘if’ – then you perform some operation – that’s the ‘and’ – and then you get some new outcome,” Baron-Cohen explains. “No other species seems to do this.”

This reasoning pattern prompts invention, and this capacity for invention underlies the many advancements the human species has made over the centuries: smartphones, rocket ships, vaccines for Covid-19. He goes on to explore how this systemising mechanism seems to present particularly strongly in autistic people. Baron-Cohen poses the question: could it really be so simple that all human invention relies on this single algorithm – and can it explain why we’ve come to dominate the planet?

Baron-Cohen defines invention in narrow terms: as being able to come up with something novel on more than one occasion, or inventing on a continuous basis – what he calls ‘generative invention’. To determine whether humans are in fact the only species capable of this generative version of inventing, he delves into the archaeological evidence and animal science to make the case that, indeed, we are.

Take our ancient hominid relatives, for example; Homo habilisHomo erectus and Homo neanderthalensis. While they exhibited innovation to a certain extent, Baron-Cohen insists they did not display a tendency to systemise or invent in a generative fashion. He points to the tools of our evolutionary cousins, the design of which hardly changed for millions of years. This lack of tool refinement means that our ancestors fail the crucial test of humanity: inventiveness. “The inventions that our hominid ancestors were coming up with were so limited, they can be more easily explained by a different mechanism – associative learning.”

About 70,000 years ago, Homo sapiens took it up a notch, Baron-Cohen says, by creating tools unlike anything we’d ever seen before. For example, the bow and arrow – the design of which clearly exhibits if-and-then thinking: if one attaches an arrow to an elastic string, and they release the tension in the string, then the arrow will soar.

Others argue that our evolutionary ancestors deserve a better rap. One of those is Rebecca Wragg Sykes, an honorary fellow in the School of Archaeology, Classics and Egyptology at the University of Liverpool and author of Kindred, a book that challenges and repaints common perceptions of the Neanderthals. She dismisses Baron-Cohen’s thesis of a cognitive revolution taking place 70,000 to 100,000 years ago – the idea, she says, has been considered outdated in archaeology for two decades.

According to Wragg Sykes, evidence of generative invention is “absolutely present” in Neanderthal archaeology. For example, Neanderthals made fire, but they didn’t just make it at random. “We know that they had pyrotechnics skills, they understood how to manage fires at different temperatures, we can see that they understood different kinds of fuels,” she says, which demonstrates causal and experimental thinking processes.

Another finding she points to is the production of birch tar amongst Neanderthals, which they used as an adhesive for tools. In order to make the resin, the process requires an intentional sequence, with the birch bark requiring heating without oxygen. Only a species that was capable of fairly complex planning and thinking would be able to create birch tar, she says. It’s more likely that any cognitive advancements occurred along a continuum, not a leap. “With Neanderthals, rather than there being a massive border in behavioural terms or cognitive terms, I think a lot of what we see us doing as early Homo sapiens is like a hyped-up version of what they’re also doing.”

Baron-Cohen does make room for the possibility of this cognitive scale-up between species as being a gradual process, rather than a revolutionary spurt as he proposes. “It could well be that there were intermediate steps between some of the hominid ancestors and Homo sapiens, and that we were beginning to see some of this mechanism in the Neanderthals,“ he says. A lot of traits in evolution come about through small tiny steps rather than one big step, and we might just be missing the intermediate steps. “If it turns out that actually Neanderthals had it too, great – we can welcome them into the tent.”

Perhaps this knack for invention isn’t specific to the first modern humans after all. But if that’s the case, then why don’t monkeys skateboard? Baron-Cohen poses this question in the book, by which he means: why don’t non-humans experiment? Delving into the science of animal behaviour, he contends that they do not exhibit an equal tendency to invent as humans have evolved to. “Your dog can learn to do all kinds of tricks, but they don’t tend to kind of generate lots of novel behaviours,” he says. There are many examples of animals displaying ingenuity, but Baron-Cohen doesn’t think non-humans have the capacity for the kind of invention that has championed human advancement – the generative kind. Rather, examples of what appear to be animal innovation can be explained away as associative learning, he says.

Lars Chittka, a professor of sensory and behavioural ecology at Queen Mary University of London, maintains there’s more to animal innovation than simple trial-and-error learning. Associative learning, Chitkka argues, is part of any innovation – human ones included. What we don’t know is whether animals are just exploring their environment randomly, and making associations on the fly, or whether they’re actively planning and thinking about their behaviour. Humans can study the process that leads to novel behaviours through language, but we can only infer what animals are thinking from their behaviour. “I think the link to associative learning does not necessarily mean that it’s not an innovation,” Chittka says.