ACT I
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Humans evolved in Africa. But for all of recorded history, we’ve lived all over the world. So what happened in between?
There has been a lot of debate about how people’s intelligence relates to the continents they live on, or that their ancestors lived on. That debate has been going on in the Americas since 1492.
This is where the story of human evolution stops being academic. Racism isn’t academic to the people it happens to.
This is part of the story of Being Human on Planet Earth where we take what we’ve talked about so far and use it to disprove misconceptions. Because effective education doesn’t just depend on telling people information. It also depends on undoing the reasons people have for not believing it.
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Intelligence means total information processing power. Or as I think of it, gross mental horsepower.
The engine in a car has a horsepower rating, which tells you how much power the engine produces. That doesn’t tell you how much of that power actually reaches the wheels, because that’s affected by other things, like how good the transmission and the drive linkage are.
If we’re going to compare two people’s intelligence, we have to be sure we’re comparing their actual brainpower. Instead of looking at it in a way that’s affected by something else. Like, how good their schools were.
The short answer is that all the evidence scientists have discovered about the evolution of human intelligence doesn’t show any meaningful connection to the part of the world anyone’s ancestors lived in. If you group people together at random and compare their gene pools for intelligence, and you group people together by the continents their ancestors lived on and compare their gene pools for intelligence, the results will be basically the same.
There are many, many genes that affect the development of our brains. The differences average out. If your group of people have 500 intelligence genes that are better than my group’s, and my group has 500 intelligence genes that are better than your group’s, that doesn’t put either of us ahead.
The continent a person’s ancestors lived on doesn’t tell us any more about their intelligence than the month they were born in does. We might as well be debating whether January Americans are smarter than February Americans.
Scientists have abandoned that line of inquiry because it shows no sign of leading to discoveries.
There are people who are convinced that continent of ancestral origin does have an effect on people’s intelligence and that if scientists haven’t found it yet, it means they haven’t searched hard enough. People can always make the, “You need to do more research,” argument against any discovery they don’t like.
Those people don’t care about science. They use science words to support what they already believed to try to sound like they aren’t just making things up, but then they leave out all the science words that contradict what they’re saying.
ACT II
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Let’s pick up the story with our ancestors spreading out from their corner of Africa 50,000 years ago. This is going to be a story about that and about the history of science at the same time. Because there are seven parts of the story where things get confusing.
The first two happen right away. First, scientists have been trying for a long time to figure out how human evolution, intelligence, and world history are connected.
Like with the study of anything else, the earliest hypotheses scientists came up were based on a lot less information than we have now. The more information we accumulate, the better the hypotheses get. Along the way, many hypotheses have been disproved. But people can still read about them.
If someone wrote a book about an idea in 1930, and then the idea was disproved in 1980, the book that was written in 1930 doesn’t tell you what happened in 1980. But this is the age of social media, and click bait, and anti-science, and Qanon, and people making money by stirring up controversy. People who don’t care that an idea was disproved can still check the book out of the library, and order it on Amazon, and turn it into a meme, and make a video about it as if it’s a new discovery.
You can pretend to prove the Earth is flat, or pretend to prove humans evolved from giraffes, or pretend to make any scientific discovery you want, as long as you tell people five or ten things they’re willing to believe and leave out all the evidence that contradicts it.
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Another point of confusion is that scientists in different fields define modern humans differently.
Physical anthropologists study anatomy. They define the origin of anatomically modern humans by the origin of people with skeletons like ours. People with skulls shaped like ours had brains shaped like ours. Brains don’t fossilize. But skulls do.
Archeologists define it the way I’ve been talking about it, as the origin of behaviorally modern humans. The best evidence of when people evolved all of our mental abilities is when they started making all the kinds of things we make.
I use 50,000 years ago as my reference point for the origin of our species for the sake of telling the story. Our ancestors were behaviorally modern humans at least 50,000 years ago and they spread out from their point of origin at least 50,000 years ago.
Even if was 60- or 70,000 years ago, that doesn’t change anything else in the story. If they spread out from their point of origin a little bit 300,000 years ago and then spread to the rest of the world later, that doesn’t change anything else in the story. Whatever version of that story you hear, those numbers don’t affect anything in everyday life.
ACT III
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Now back to our story of our ancestors, 50,000 years ago. They spread from their corner of Africa to the rest of Africa and then into Asia and Europe.
Earlier species of humans had already been living in Asia and Europe for about a million years, and in other parts of Africa for several million. The Neanderthals lived in Europe and parts of Asia. Other species lived in other parts of Africa and Asia.
Our ancestors were smarter than all of them. Our species used inventions to adapt to living in all the environments on Earth where people live now.
One way or another, all the other species went extinct. For the most part, that is.
Recently some scientists started studying Neanderthal genes and comparing them to Europeans’ genes. They discovered that the Neanderthals were closely enough related to our ancestors that they could still have children together. It turns out that people whose ancestors came from Europe are about 3% Neanderthal. So things like that probably happened in other places too.
That means the Neanderthals must’ve been pretty intelligent also. Even though our Homo sapiens ancestors were smarter than them, the Neanderthals and those others had lived in their environments much longer. So they were better adapted to them physically.
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Now let’s skip to 40,000 years ago. That’s when humans spread into Australia for the first time.
The only way they could’ve gotten there was in boats. It seems surprising at first that people 40,000 years ago knew enough about building boats and navigating that they could sail from south eastern Asia to Australia. But then again, they had our level of intelligence at that point.
There are thousands of islands between Asia and Australia, and by then people could’ve been building and sailing boats there for thousands of years. The ocean level was lower at the time, so they didn’t have to sail as far to get from one to the other. But the ocean level never got low enough that they could’ve gotten there without boats.
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Now let’s skip to 14,000 years ago. At that point archeology shows a lot of evidence of humans in the Americas.
For a long time people thought that the last ice age lowered the sea levels and turned the Being Strait into a land bridge and people walked into the Americas. But if people who lived by the ocean could’ve built boats to sail from Asia to Australia 26,000 years earlier, crossing the Aleutian Islands in boats would’ve been easy any time after that.
People didn’t come to the Americas all in one wave. Some people crossed the Aleutians later. Some other people could’ve crossed them earlier.
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Now let’s skip to 10,500 years ago. All of the continents were inhabited by the descendants of the people from east Africa, and had been for at least 3,000 years. Many islands had people living on them also, and people kept spreading to more islands.
That’s when the first group of people developed farming. That was in the Middle East. People in at least four other parts of the world developed farming later on.
They didn’t develop farming because they were smarter than anyone else. They developed it because hunting and gathering wasn’t producing enough food for their population sizes anymore, and because they had a number of environmental factors that let them discover a new form of food production.
The development of agriculture led to population growth, cities, kingdoms, the Bronze Age, writing, and all the things that followed from them.
Those weren’t because the people who thought of them were smarter than anyone else either. Those were because farming produced more food than hunting and gathering, and that led to big changes in their societies.
More food meant people could feed more children. That meant population growth. That created cities.
Bigger population sizes meant more people to organize. That meant new forms of government. That’s what kingdoms were.
More people and new forms of government meant more information to keep track of. That’s what writing was invented for.
The development of farming and the developments it led to are two more chapters in the story of Being Human on Planet Earth, which we’re working up to.
ACT IV
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Now for the other five arguments.
First there’s genetic drift.
Variations happen essentially at random. If a species is split into two groups that live in environments that are essentially the same, and they’re separated from each other for many generations, some variations are going to appear between the two groups at random. Even if the two groups start out with identical gene pools, genetic drift changes their gene pools gradually.
Some characteristics become more common in one group and other characteristics become more common in the other group. But if they have no effect on survival or reproduction rates, they never become traits.
Variations that aren’t affected by selection pressures are just random changes. They happen to people all over the world. So there’s no path we can follow to see how genetic drift could’ve made one group of people better at something than another group.
For instance, in different parts of the world people have different patterns in the shapes of their teeth. But they’re characteristics, where certain dental patterns are more common than others; they aren’t traits. So while it is true that people whose ancestors came from different parts of the world have differences in their dental patterns and have differences in the color of their skin, there’s no connection between the two. If you’ve curious what a person’s teeth look like, their race doesn’t answer the question.
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Next is the physical environment argument.
As people spread through the world they evolved to their different environments. We all need to absorb the right amount of sunlight through our skin to produce vitamin D, so we can be healthy, but without getting sunburnt. People who lived near the equator had dark skin and people who lived closer to the poles had lighter skin. Because the sun shines much more directly on the equator than it does on higher latitudes.
Environmental factors affected the shapes of our eyes and noses and lips, and textures of our hair. Eventually our ancestors evolved different blood types, which helped them digest the foods that were available in their different parts of the world and resist the diseases that lived there.
If people evolved physically to different parts of the world, doesn’t that mean they would’ve evolved mentally also?
Wherever people lived, their intelligence evolved to some extent to make them better at thinking about how to live in that physical environment. And that was true for everyone else in the world. Again, that tells us that our gene pools aren’t identical, but it doesn’t show us any clues that one group of people would be smarter than another.
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Next is the harsh environment argument.
Evolution is always a competition between a species’ gene pool and its environment. Some places people live are more hospitable to people than others. The harsher the environment, the more ways there are to die.
If you live in a harsh environment and the things that can kill you are things you can outsmart, it means most of the people who die will be the ones who didn’t outsmart them. In a part of the world with fewer ways to die, less intelligent people survive.
That makes the average level of intelligence in the gene pool in harsh environments higher than the average level of intelligence in the gene pool in a more favorable environment.
As it turns out, the myth of the Garden of Eden actually does have some basis in real life. The first place on Earth where people developed farming was in the Middle East because at the time it had the most favorable environment in the world for people.
But the most favorable environment doesn’t create the strongest gene pool. The most favorable environment creates the weakest gene pool. The environment with the fewest ways to die creates the lowest average levels for survival abilities. But at the same time it also gave people the best combination of resources, which more than made up for it.
The first empires of the Middle East arose for the same reason Europeans went on to conquer most of the world. A huge number of well fed people, with the best animals, tools, weapons, armor, armies, and information processing to help them are a more physically powerful civilization than a smaller number of people with less of all those things, but who are genetically stronger and more intelligent as individuals.
The other, even bigger, problem with the harsh environment argument is that the effects are only temporary. Most people in the world choose an easier life with fewer ways to die whenever they get the chance. Do you really want to have eight children so that the two with the best genes can live and the other six can die? Some men might like that idea, but hardly any women do.
ACT V
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Next, there’s the historical choices argument.
Wherever some historical event can be defined by choices people made, or their mental reaction to a situation, people whose genes gave them personalities that would favor that choice or that reaction could end up in one part of the world. All the White people who were born in America are descended from Europeans who dared to move across an ocean, and all the White people who were born in Europe aren’t.
But how much does that tell us? The same thing can be said for White people who were born anywhere in the world outside of Europe. How much does one basic difference among our ancestors’ personality typestell us about the histories and current events of all of our countries?
And it’s not like moving to other continents was the only adventurous thing Europeans ever did. Every ship that ever sailed away from Europe and then sailed back to Europe was sailed by White people too.
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Finally, there’s the IQ argument.
When IQ test results are grouped by which continents the people’s ancestors lived on, there are some differences. That suggests that the differences in our gene pools for mental abilities might be a little bit different from groups of people chosen at random.
The first problem with that is that an IQ test doesn’t measure people’s intelligence at the genetic level. It measures the effects of their intelligence genes, combined with everything that’s happened to the person in their life up until the time they took the test. It doesn’t say anything about economic, political, social, cultural, or regional effects that have happened to people because of their race, like how good of prenatal care their mothers got, how healthy their diet has been, how good their schools were, how much lead there was in their drinking water, or how they prepared for the test.
The other, even bigger problem with this argument is that it runs into the Law of Diminishing Returns. All the time and money people have invested into researching this has revealed some minor differences. How much more time and money should we invest in this? Is understanding those differences better than we understand them now worth the time and money it would take? What would understanding thisbetter help us do?
There are no situations in life where people who have a serious interest in another person’s intelligence would believe that the person’s race would be the best way to determine it. If you need a hundred intelligent people to do a job, you don’t go hire the first hundred Asian people you see.
The only people who feel that the evidence we have warrants further investigation don’t really care about science. What they really care about is xenophobia, where they assume their own group of people must be smarter than any other group, so they’re convinced there must be some evidence scientists can discover.
ACT VI
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Usually I like to refer you to books where you can learn more. Any introductory book about evolutionary psychology is about how human intelligence evolved. There aren’t any evolutionary psychology books about how race affected the evolution of intelligence, because you can’t write a science book about something that has no real evidence to suggest that it happened.
None of those seven arguments point to the people from any part of the world being more intelligent than the people from any other part of the world in any meaningful way. All of these explanations of how people’s intelligence could’ve evolved differently in different parts of the world failed because they overlooked one simple thing.
They started by asking the wrong question.
It’s not: How did the environments in different parts of the world affect the evolution of our intelligence after our ancestors spread out?
It’s: How much did the environment affect the evolution of our intelligence before our ancestors spread out?
It’s easy to see a lot of differences among people from different continents. But those don’t show us differences in our intelligence. They show us how powerful human intelligence is.
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1,000 years ago, when the fastest people could travel was on horses or sailing ships, our ancestors were much more separated from each other than we are now. Different parts of the world were different environments from each other. And wherever on Earth people lived, it means people used their intelligence to adapt to whatever life was like there.
Physically our ancestors evolved genetically to their different environments.
Mentally we evolve by learning.
Genes evolve by children growing up to have children of their own.
Ideas evolve every time you change your mind about something.
That’s the power of human intelligence. That’s the next chapter in our story of Being Human on Planet Earth.
