The Cultural Origins of Human Cognition

"This is one of the earlier attempts to consider cultural and genetic evolution. He is interested in something he calls the ‘ratchet’ effect. This is something we only see in humans. Humans can produce novel ideas, behaviours, and practices, and our cultural learning is sufficiently high fidelity, that the next generation can get those ideas and practices and bodies of knowledge and build on it incrementally, so that, over generations, you have this accumulation of cultural know-how. Now other animals can learn from each other, but the loss of information between generations is sufficiently high that they never get anywhere. They never get this accumulation of more and more know-how over generations — at least as far as we know, and, if they do, it is pretty light. So Mike is interested in how we got that because there’s a question in human evolution of how our brains got so big so quickly. It would seem to demand what researchers call an ‘autocatalytic process’ — the process had to fuel itself. It had to get stronger and stronger. Gene cultural co-evolution can provide that. So if you have a little bit of cumulative cultural evolution: you get some fancier tools and a larger body of knowledge, then there is greater selection pressure for bigger brains that are better at acquiring, storing, and organising that information. Then, once you have brains that are better at doing that, you’ll get more cultural information. So the body of know-how will become larger. Then you need an even bigger brain that’s even better at that stuff. Mike looks at this ratchet process and he argues that the key adaptation was what he calls ‘theory of mind’ or ‘mentalizing’. The fact that humans are particularly good at inferring what other members of their social group are thinking allows them to be better social learners, and that gives them the high fidelity transmission of knowledge across generations which gives you the ratchet effect. He makes the case that there’s one big genetic adaptation, theory of mind, and that that then generates the ratchet process. He also argues that language is a product of the ratchet process, that you get fancier languages and grammars over time. He’s a comparative developmental psychologist, so a lot of his evidence comes from comparing humans and chimpanzees or other primates and apes, and at the way children accrete knowledge when they are learning a language. You can compare that with communication systems in another species. Those are his main data sources. He looks at the ways culture accumulates over time. Lots of subsequent work has borne Mike out on that the key element in getting cumulative cultural evolution, which is high fidelity cultural transmission. You get faster and fancier tools the higher fidelity the transmission. There’s lots of ways to increase fidelity—people or animals can get better at learning from others—but they can also become more social and hang around each other more. You can also have the evolution of teaching, where the transmitter actively helps out the learner and helps make sure they pass on the knowledge. Teaching seems to be something that’s particularly important for human cultural transmission, although there’s lots of cultural variation in that. The books also got me thinking about language. I assumed that a lot of language learning was innate, or that we had lots of pre-built, evolved machinery for it. In my book, The Secret of Our Success, I make the case that languages, actually have, even in historical time, gotten more complex, added new tenses, added new grammatical tools, vastly increased the repertoire of vocabularies, gotten more phonemes, and all kinds of things that go along with the rise of complexity. So languages are really just like other domains of culture—like tools—in that they are cumulative and depend on the size and inter-connectedness of populations. It’s been hugely influential. It’s created whole research programmes and driven lots of research. I part ways a little bit with Mike here and there on what it takes to get the high fidelity cultural transmission. In the case of humans, I argue that it wasn’t some magic genetic bullet that allowed humans to get cumulative cultural evolution, but that we’re a primate and that we had, maybe, chimpanzee-like social learning, but that we lived in a different social structure, and it was actually differences in social structure which allowed humans to begin this cumulative accumulation of knowledge. It was a change to greater sociality. So there was no difference in learning ability, but more people to learn from, more sociability and more tolerance allowed humans to cross the divide and begin down this road of gene cultural co-evolution. Various ideas of Mike’s have become widespread. Some have been disagreed with, but in terms of the general importance of the ratchet effect, and cumulative cultural evolution, that seems quite mainstream at this point. Yes, it is a good test of the ‘collective brain’ idea. If the collective brain idea is right, when we look back historically on this period, the early 21st century, we should see a massive increase in rates of innovation because of all the interaction the new communication technology is permitting."

"This book I am equally or even more persuaded by. Tomasello argues that evolution must have endowed us with something uniquely powerful. He says the only possible solution to the puzzle of this explosion in creativity, the only biological mechanism that could have brought about these changes in such a short period of time, is a new capacity for social and cultural transmission. In other words, what he’s saying is that there is a new, uniquely powerful way of social learning. He says you can see how evolution has endowed animals with a more simple form of social learning: for instance, rat pups only eat food that their mother eats, they learn from what their mothers eat. Young birds learn their species’ typical songs by mimicking their parents. His argument is that this simple ability to learn from our fellows, not in a conscious way – animals don’t do it in a conscious way, is something evolution has endowed them with – stopped at some stage in our evolutionary past and became transformed into something a lot more powerful. What is unique about our form of social learning is that we are able to imitate and that we are able to learn things co-operatively – whilst animals are not able to think about what their fellows are doing or what they themselves are doing. We can look at what somebody else is doing and we can make inferences about their goals and intentions. What they are trying to do here? What is the intended outcome of what they’re doing? And we can look at how they actually do it, the various steps towards achieving the end product and we can look at the end product. While all the experimental studies point very persuasively to the idea that apes are only able to look at the outcome. For a while people thought apes could ape. No, they can’t. Not in the human way. They can look at the outcome of what somebody has done, and then they have to invent a way of achieving that through trial and error. So in an experiment they might see a human being using a rake to pull something towards them. Then they might realise, ‘Oh, a rake can be used as a tool.’ But they don’t understand the how. Through trial and error they might achieve the same result, or get the same result in a different way. This is why, I would argue, in the right conditions, a clever ape could invent all the ape behaviour that we see today. An ape that is clever enough could invent all of the different ways that apes use tools, while it’s absolutely not the case that ANY human being, however clever they are, could invent from scratch X-rays, combustion engines, the harnessing of electricity – everything that humans have achieved. Yes, between 100,000 years ago and 30,000 years ago. We split from the chimpanzee six million years ago, and you see some changes in tool use with homo erectus, and there’s not that much evidence from the time of homo habilis, I don’t know why. You see some evidence of changes in tool use, slightly more sophisticated, over millions of years. And then, suddenly, after homo sapiens, approximately 60,000 years ago, you see this cultural explosion. Just the ability to teach and learn from each other meant that the skills and discoveries and innovations of the most intelligent group members would then quickly be passed on to other group members. And each generation could learn from the insights of previous generations and build up on those insights. It’s a very difficult thing to try to understand how evolution could have given us what we have. How can we ever get an answer to it? These are just two theories. There is a lot of overlap and they complement each other in a lot of ways. They both recognise the importance of language. Tomasello is saying that a simpler form of social learning exists, that might have become transformed into the kind of social learning that we have, where we can actually truly imitate. He argues that this emerged out of our innate desire to engage with others about the world around us. And from developmental psychology there’s lots of evidence of an infant’s innate desire to engage emotionally with other human beings, which brings me on to my next book, which looks at it from the ontogenetic line of development."