http://edge.org/conversation/infinite-stupidity-edge-conversation-with-mark-pagel
[MARK PAGEL:] I'm an evolutionary biologist, and my work draws me to the big events that have shaped the history of the world. Some of these we agree upon, and others are right under our noses, and yet we take them for granted and we may not appreciate what a force they've been in our evolution. One of those is the human capacity for culture. It might easily be the most important event in the history of life.
It might be useful, with such a statement like that, to review some of these big events. Obviously one of the big events in our history was the origin of our planet, about 4.5 billion years ago. And what's fascinating is that about 3.8 billion years ago, only about seven or eight hundred million years after the origin of our planet, life arose. That life was simple replicators, things that could make copies of themselves. And we think that life was a little bit like the bacteria we see on earth today. It would be the ancestors of the bacteria we see on earth today.
That life ruled the world for 2 billion years, and then about 1.5 billion years ago, a new kind of life emerged. These were the eukaryotic cells. They were a little bit different kind of cell from bacteria. And actually the kind of cells we are made of. And again, these organisms that were eukaryotes were single-celled, so even 1.5 billion years ago, we still just had single-celled organisms on earth. But it was a new kind of life.
It was another 500 million years before we had anything like a multicellular organism, and it was another 500 million years after that before we had anything really very interesting. So, about 500 million years ago, the plants and the animals started to evolve. And I think everybody would agree that this was a major event in the history of the world, because, for the first time, we had complex organisms.
After about 500 million years ago, things like the plants evolved, the fish evolved, lizards and snakes, dinosaurs, birds, and eventually mammals. And then it was really just six or seven million years ago, within the mammals, that the lineage that we now call the hominins arose. And they would be direct descendants of us. And then, within that lineage that arose about six or seven million years ago, it was only about 200,000 years ago that humans finally evolved.
And so, this is really just 99.99 percent of the way through the history of this planet, humans finally arose. But in that 0.01 percent of life on earth, we've utterly changed the planet. And the reason is that, with the arrival of humans 200,000 years ago, a new kind of evolution was created. The old genetical evolution that had ruled for 3.8 billion years now had a competitor, and that new kind of evolution was ideas.
It was a true form of evolution, because now ideas could arise, and they could jump from mind to mind, without genes having to change. So, populations of humans could adapt at the level of ideas. Ideas could accumulate. We call this cumulative cultural adaptation. And so, cultural complexity could emerge and arise orders and orders of magnitude faster than genetic evolution.
Now, I think most of us take that utterly for granted, but it has completely rewritten the way life evolves on this planet because, with the arrival of our species, everything changed. Now, a single species, using its idea evolution, that could proceed apace independently of genes, was able to adapt to nearly every environment on earth, and spread around the world where no other species had done that. All other species are limited to places on earth that their genes adapt them to. But we were able to adapt at the level of our cultures to every place on earth.
A lot of that sounds familiar to us. But what's hidden in there is this idea of idea evolution. And if it seems easy to us, it shouldn't, because no other species on earth has been capable of doing it. And I'm including in this our recent ancestors.
If we go back in our lineage 2 million years or so, there was a species known as homo erectus. Homo erectus is an upright ape that lived on the African savannah. It could make tools, but they were very limited tools, and those tools, the archaeological record tells us, didn't change for about 1.5 million years. That is, until about the time they went extinct. That is, they made the same tools over and over and over again, without any real changes to them.
If we move forward in time a little bit, it's not even clear that our very close cousins that we know are related to us 99.5 or 99.6 percent in the sequences of their genes, the Neanderthals, it's not even clear that they had what we call idea evolution. Sure enough, their tools that they made were more complex than our tools. But the 300,000 or so years that they spent in Europe, their toolkit barely changed. So there's very little evolution going on.
So there's something really very special about this new species, humans, that arose and invented this new kind of evolution, based on ideas. And so it's useful for us to ask, what is it about humans that distinguishes them? It must have been a tiny genetic difference between us and the Neanderthals because, as I said, we're so closely related to them genetically, a tiny genetic difference that had a vast cultural potential.
That difference is something that anthropologists and archaeologists call social learning. It's a very difficult concept to define, but when we talk about it, all of us humans know what it means. And it seems to be the case that only humans have the capacity to learn complex new or novel behaviors, simply by watching and imitating others. And there seems to be a second component to it, which is that we seem to be able to get inside the minds of other people who are doing things in front of us, and understand why it is they're doing those things. These two things together, we call social learning.
Many people respond that, oh, of course the other animals can do social learning, because we know that the chimpanzees can imitate each other, and we see all sorts of learning in animals like dolphins and the other monkeys, and so on. But the key point about social learning is that this minor difference between us and the other species forms an unbridgeable gap between us and them. Because, whereas all of the other animals can pick up the odd behavior by having their attention called to something, only humans seem to be able to select, among a range of alternatives, the best one, and then to build on that alternative, and to adapt it, and to improve upon it. And so, our cultures cumulatively adapt, whereas all other animals seem to do the same thing over and over and over again.
