The Out of Africa Hypothesis, Human Genetic Diversity, and Comparative Economic Development
Quamrul Ashraf and Oded Galor
Forthcoming in the American Economic Review
Abstract
This research advances and empirically establishes the hypothesis that, in the course of the prehistoric exodus of Homo sapiens out of Africa, variation in migratory distance to various settlements across the globe affected genetic diversity and has had a long-lasting hump-shaped effect on comparative economic development, reáecting the trade-offs between the beneficial and the detrimental effects of diversity on productivity. While intermediate levels of genetic diversity prevalent among Asian and European populations have been conducive for development, the high diversity of African populations and the low diversity of Native American populations have been detrimental for the development of these regions.
Economics and genetics meet in uneasy union
Use of population-genetic data to predict economic success sparks war of words.
Ewen Callaway
10 October 2012
The United States has the right amount of genetic diversity to buoy its economy, claim economists.
“The invalid assumption that correlation implies cause is probably among the two or three most serious and common errors of human reasoning.” Evolutionary biologist Stephen Jay Gould was referring to purported links between genetics and an individual’s intelligence when he made this familiar complaint in his 1981 book The Mismeasure of Man.
Oh, boy, here we are in 2012 and “Nature” is still citing the authority of Stephen Jay Gould’s dopey and discredited 1981 bestseller as an unquestioned authority text …
Fast-forward three decades, and leading geneticists and anthropologists are levelling a similar charge at economics researchers who claim that a country’s genetic diversity can predict the success of its economy.
To critics, the economists’ paper seems to suggest that a country’s poverty could be the result of its citizens’ genetic make-up, and the paper is attracting charges of genetic determinism, and even racism. But the economists say that they have been misunderstood, and are merely using genetics as a proxy for other factors that can drive an economy, such as history and culture. The debate holds cautionary lessons for a nascent field that blends genetics with economics, sometimes called genoeconomics. The work could have real-world pay-offs, such as helping policy-makers to set the right level of immigration to boost the economy, says Enrico Spolaore, an economist at Tufts University near Boston, Massachusetts, who has also used global genetic-diversity data in his research.
Spolaore then writes in to Nature to say that he never ever said anything about the I-word.
Here's Spolaore's upcoming review of all non-crimethink theories of why some countries are richer than others. It's pretty good, but the only marginally non-PC thinker it cites is Gregory Clark. Lynn & Vanhanen and Rindermann are conspicuous by their absence, as is Michael Hart, whose theory that winter makes people smarter due to natural selection seems to be the most plausible explanation of Spolaore's own research showing a major role for "absolute latitude." Spolaore's main focus is "long-term genealogical relatedness," which is a very good thing to think about, but intellectual life has gotten so thuggish that anybody thinking useful thoughts has to tread carefully these days to not attract the thugs.
To return to Nature:
But the economists at the forefront of this field clearly need to be prepared for harsh scrutiny of their techniques and conclusions. At the centre of the storm is a 107-page paper by Oded Galor of Brown University in Providence, Rhode Island, and Quamrul Ashraf of Williams College in Williamstown, Massachusetts1. It has been peer-reviewed by economists and biologists, and will soon appear in American Economic Review, one of the most prestigious economics journals.
The paper argues that there are strong links between estimates of genetic diversity for 145 countries and per-capita incomes, even after accounting for myriad factors such as economic-based migration. High genetic diversity in a country’s population is linked with greater innovation, the paper says, because diverse populations have a greater range of cognitive abilities and styles. By contrast, low genetic diversity tends to produce societies with greater interpersonal trust, because there are fewer differences between populations. Countries with intermediate levels of diversity, such as the United States, balance these factors and have the most productive economies as a result, the economists conclude.
The manuscript had been circulating on the Internet for more than two years, garnering little attention outside economics — until last month, when Science published a summary of the paper in its section on new research in other journals. This sparked a sharp response from a long list of prominent scientists, including geneticist David Reich of Harvard Medical School in Boston, Massachusetts, and Harvard University palaeoanthropologist Daniel Lieberman in Cambridge.
Mostly anthropologists at Harvard. Unfortunately, the PC critique is intellectually lame and misses the actual flaws in Galor and Ashraf's paper.
In an open letter, the group said that it is worried about the political implications of the economists’ work: “the suggestion that an ideal level of genetic variation could foster economic growth and could even be engineered has the potential to be misused with frightening consequences to justify indefensible practices such as ethnic cleansing or genocide,” it said.
The critics add that the economists made blunders such as treating the genetic diversity of different countries as independent data, when they are intrinsically linked by human migration and shared history. “It’s a misuse of data,” says Reich, which undermines the paper’s main conclusions. The populations of East Asian countries share a common genetic history, and cultural practices — but the former is not necessarily responsible for the latter. “Such haphazard methods and erroneous assumptions of statistical independence could equally find a genetic cause for the use of chopsticks,” the critics wrote.
They have missed the point, responds Galor, a prominent economist whose work examines the ancient origins of contemporary economic factors. “The entire criticism is based on a gross misinterpretation of our work and, in some respects, a superficial understanding of the empirical techniques employed,” he says. Galor and Ashraf told Nature that, far from claiming that genetic diversity directly influences economic development, they are using it as a proxy for immeasurable cultural, historical and biological factors that influence economies. “Our study is not about a nature or nurture debate,” says Ashraf.
“To this end, our work employs migratory distance from East Africa (i.e., distance along land-connected routes) as an “exogenous” source of variation in intrapopulation diversity across regions. Put differently, rather than directly employing the observed diversity measure, which may be tainted by genetic admixtures resulting from movements of populations across space in response to spatial differences in economic prosperity, we employ the variation in the diversity measure that is predicted by distance along prehistoric migration routes from East Africa.”
42 comments:
Economists seem to have been dabbling in all sorts of fields that would seem to be out of their usual purview. The occupation itself must not be very exciting, hence the desire to go from being half-baked in one field of endeavor to being incompetent in many.
that the old saw about how Africans are the most genetically diverse is really meaningful, when population geneticists try hard to find the least important genes to track.
I think the reliance on unimportant genes ("junk" DNA) has really distorted our modern understanding of race and probably other areas of taxonomy too.
For example phenotypically sub-Saharan Africans and the indigenous "blacks" of Southeast Asia and Oceania (australoids) seem to be broadly definable as all members of a single negroid race, however because of "junk" DNA, they are instead considered completely different races with little genetic similarity.
Junk DNA, because it's unimportant, is by definition not sensitive to natural selection, and thus serves as a measure of random mutations that occur regularly overtime and is thus useful for estimating the time since two populations diverged. Because sub-saharans and australoids diverged so long ago, they are wildly different in junk DNA and considered completely different races.
However I think it's much more meaningful to define race as people who have genetically preserved the phenotype of their common ancestor (regardless of how long ago that common ancestor lived). But but by using junk DNA, geneticists imply that races (or the more politically correct term, population/genetic cluster) are people who have a recent common ancestor (regardless of whether they preserved its phenotype).
By my definition of race, australoids and sub-saharan Africans are both "negroids" and there are probably only 3 races (the other two being caucasoids and mongoloids). But because geneticists insist on using the most unimportant genes to classify race, we get a much more complicated taxonomy.
Since when does the United States have 'intermediate levels of genetic diversity'? The United States today is probably more genetically diverse than just about anyplace one earth. It is somewhat more homogeneous among older age cohorts, but it's no longer anything like Europe. If their theory is applied correctly, then the United States is a disaster waiting to happen.
Oh, wait...
FWIW, I don't doubt the advantages of having strong-but-not-too-strong genetic similarities among a population, but it seems too convenient to make it some sort of unified field theory for why some regions prosper and others don't. Greece, Mesopotamia, and the Levant are all pretty damn close to East Africa, but their populations made huge contributions in earlier times to advancing human civilization. Africa might have, too, had it been geographically and climatologically better suited to developments which lead to civilization.
Also, quite simply, the succeess of Out of Africa populations might've had a little something to do with selection effect: those populations who were curious enough to wonder "what's over there" and smart enough to survive the journey might've had an initial genetic advantage over those who stayed behind, or drowned or died of dehydration along the way.
Random events, random circumstances, and random mutations are what lead to the differing economic prosperity we see today.
"Are we ever going to make any intellectual progress?"
In a word, no. Oh, sure, some dissidents will always pick around the edges, (re)discovering truths and passing them on to dissidents in the next generation. But I'm not as optimistic as Derb that Science is going to force us to see reality. We already have plenty of evidence of race realism, yet the average person's view of race is further from reality than it was a century ago.
If I start to think we're making progress, I just go read some Chesterton, or quotes from some old Romans, or various thinkers in between. They probably hoped they were making progress too, but there's nothing new when it comes to the human condition and our capacity for self-deception, except that we've developed more powerful tools for controlling what masses of people think.
Something else that bothers me about this hypothesis is this notion that Africa has the highest levels of genetic diversity. Anyone observing the behavior of American blacks knows that blacks are phenotypically just about the most predictable population we have - politically, culturally, however. It's true that American blacks aren't necessarily a random sampling of African blacks, coming mostly from West Africa, but then that would just suggest there are places within Africa that have higher degrees of genetic similarity than "Africa."
Populations have to be similar enough to work together and different enough to approach problems differently, but mere diversity is insufficient to explain success or failure.
Their paper might be bs but at least they got themselves noticed. Too bad none of the mainstream people who reviewed their paper noticed any of the glaring problems you did.
obviously there's more COGNITIVE diversity (i.e., larger standard deviations) in whites than in blacks.
Astonishing. These guys probably really believe what they wrote.
Without evolution/ Darwinism and logical thinking, regardless of it unpleasant consequences, nothing makes much sense in the world.
Like this paper. Distance to Africa? Well, those Falklanders must be the least genetically diverse people ever!
Are we ever going to make any intellectual progress?
No.
Economists never cease to amaze in their ability to focus on purely academic idealizations and totally ignore the real world.
According to Wikipedia Bolivia today is 55% Amerindian, 30% Mestizo and 15% white. How could
anyone be so stupid as to believe that it is the least diverse country in the world?
What is wrong with economists?
Steve, it's bad enough these guys are going to get hounded out of academia and out of polite society. You want to go ahead and get them torn apart by angry mobs. Thanks a lot.
--Discordiax
One reason that economists, at the top level very bright people, are increasingly saying idiotic things is that the smartest and best-educated economists almost always work in one of two sectors, government and academia, which are on certain subjects among the most intellectually corrupt sectors of our society.
The more false and pernicious the theory, the more torturous and absurd are the rationalizations. And it's all reduced to a rigid scoring system in which the criteria is how well a given socialist economy is performing which is in turn determined by false government statistics. The bottom line is that the Golden Age of the Modern West was when our countries were close to homogenous and Whites were officially in charge. Anything that denies the basic truth and virtue of that is a social pathology. Of course if we get another chance we really must avoid indulging ourselves in White vs. White world wars.
From now on, all econ majors should be required to have a double major, the other being evolutionary biology. However, before being given the degree, they must pass a test on evo, a hard test, maybe one designed by Cochran. (big smile at the thought)
Genetics probably has a major influence on the competence and productivity of different populations. That said, these economists have no idea what they're talking about.
So according to the paper, if we could create a country that is half Bolivian and half Ethiopian, we could get just the right amount of genetic diversity and have a better economy.
I thought human migration patterns were more like many waves leaving Africa over the last 200-50 thousand years, but with some waves also returning back.
Maybe I'm confused and this actually describes hominid migration patterns, and extends further back in time to several million years, but it still probably informs current human genetic diversity within Africa.
The way I've learned it (from my evolutionary anthropologist grandfather and a bunch of books and documentaries I've obsessively looked at) that arrow of human migration that grows out of Africa through the Suez peninsula and then spreads leftward across Europe, rightward across Asia, up over the Bering Strait and down across the Americas is a major simplification. Up close the arrow turns in on itself, grows all kinds of smaller curls, and partially reverses direction several times. The genetic consequences of this have to be way more complicated than Ashraf and Galor seem to claim.
obviously there's more COGNITIVE diversity (i.e., larger standard deviations) in whites than in blacks
I'm not convinced that's the case. The higher SD in whites has not consistently been found (I've seen studies showing the opposite) and the quality of the racial sampling used in IQ testing is not sufficient to draw such a conclusion. Also there are floor effects on IQ tests (not enough easy questions) that artificially limit the variability of black IQ at the low end thus spuriously shrinking the SD.
Also blacks in America are not a representative sample of the entire black race.
Another reason to doubt a small SD is that a dark skinned black scored an IQ of 200 (though this was on the old Binet ratio IQ scale which was notoriously for producing absurdly high scores)
What all those mainstream researchers are in need of is logic, pure and simple.
There is no such thing as junk DNA. Every strand has a purpose.
@steve - "...that the old saw about how Africans are the most genetically diverse is really meaningful...."
maybe it is meaningful, but just (or partly) as an indicator that a large part of africa straddles the equator?
It's all a load of toffee from people who don't know what they are talking about (literally).
Scientifically, this paper should be treated with the same contempt as any of the tosh emanating from 'young earth creationists' or similar charlatans.
For starters, the many peoples of Europe are amongst the least diverse peoples on earth - as they all cluster very close together genetically.
Nobody's commented on the HBD aspect of this yet? You've got an Arab and an Israeli against legions of American Jews.
Actually fits what I've observed about the political stances of Israelis and American Jews, actually.
Atleast they are looking at genes to try to assign a cause to human differences.
Still their hypothesis is testable, certain groups in South America share both the too diverse african junk genes, and the not diverse enough injun genes correct? Those areas must rock economically speaking, they've even been around longer than America has.
eh, didn't australian scientists just recently complete a 100 year long study into the genes of the aboriginies, and found, using year 2012 lab equipment on year 1912 genetic samples, that aborigines have an unbroken, undiluted genetic history of "pure" aboriginal genes going back 50,000 years?
that is to say, all evidence we have from the field of biology suggests that once aboriginies were on australia, they alone occupied the continent for millenia, with no outside humans coming in or having sex with any of them, at all, whatsoever.
during this time, they developed almost nothing, which is what the evidence from archaeologists, geologists, and anthropologists suggests. so the most genetically isolated group scientists have ever found, are probably the least accomplished.
meanwhile, the koreans, who are some of the most insular people who have ever existed, are over 99% korean and even less genetically diverse than the japanese and han chinese. they have developed a modern technological society in south korea in only 50 years, mainly by copying western europeans. most peoples of the world do not even show this ability - to simply emulate what the western europeans are doing. australian abos are in direct contact with western europeans daily and have been for the last 200 years, yet show no signs of even minor emulation.
these hypotheses from economists just don't wash.
Steve, I am astonished you'd say Junk DNA is junk when current research says it is NOT. Indeed the non-coding DNA controls organ/metabolism function and turns off/on various DNA codes themselves. So its hardly junk.
Diverse genes are not themselves predictive. Humans migrated out of Africa because it was an unpleasant place to live, full of disease, existing humans, and subject to droughts.
Before Industrialization, take say 1400, China was quite uniform, and had the highest standard of living and greatest GDP such as it was. Europe was more genetically diverse (and linguistically, and politically); and was lower than China. If you then look at industrialization, some places (England, France, and Germany) did well, others less well (Italy and Spain) and others almost non-existent (Russia, the Ottoman Sultanate). Japan industrialized, China did not.
Politics, culture, individual "great men" for good or ill, all come into play.
Genetics can tell you what obviously does not work: highly diverse genetic makeup. At no time or place has that been a recipe for social success. But the thesis itself (middle-ground genetic diversity is the best) is disproven by Iceland. Iceland is as mono-racial and least genetic diverse as possible, and is much richer than Bolivia despite lacking much in the way of resources, compared to say Bolivia.
And as a follow-up, it is likely the tropical disease load killed urbanization and the interplay between culture, politics, and natural selection that helped propel more urban (but not too much) NE Asia and Western Europe to the fore. As you noted, Africa pre-modern times was not suited to cities. In places like the ME, cities arose 10,000 years ago, around the time of agriculture (Jericho has been inhabited almost continuously for that long). In places like Egypt, Mesopotamia, India, and China, terrain and political unity created a God-King/Serf social structure that did not allow (along with widespread slave/serf labor) for innovation.
The Greeks created analog computers, and primitive steam engines, and did nothing with them, given labor a plenty and a two-tier, royalty/servant class structure. The Chinese invented gunpowder, very good for killing people like your enemies, but did nothing with it.
Labor-short Europe, with independent social classes, plenty of enemies willing to innovate (if you the king did not), adopted gunpowder like crazy, when the Chinese and Japanese did not. Killing off feudalism and the knightly class very shortly. In a way the Samurai would not allow themselves to be destroyed, the Knights certainly were. An army of 20,000 poorly paid peasants trained minimally with arquebuses and cannons beat the best 5,000 knights in the land (who cost maybe three times as much as the peasants did).
Genetically I think this speaks to selection for adaptation, in a small population size group under both warring and environmental pressure. And also radically different family formation: no random polygyny or hard polygamy but mostly monogamy -- a feature even Tacitus comments on.
People of European background rely too much on genetics. Jews, East and South Asians don't let the predetermined nature of genetics get in the way of them studying for standardized tests among many other things. Some European people seem to think that everything's done with genetics so they don't have to do anything. So what if a large part of what we see in the world today is because of genetics? There still is an environmental impact on human behavior.
Whiskey, I don't believe China had the highest standard of living before 1400. I think the pictures of everyday Chinese from the late 1800s and early 1900s was the way it was for the vast majority of Chinese throughout history. Most Chinese were toilers. There only existed a tiny leisure class. Despite what many Western people assume monogamy did not exist in East Asia. Male infidelity was and still is accepted.
"Junk DNA, because it's unimportant,"
i just posted about this in the nobel prize thread. it has recently been discovered that so called junk DNA actually has a function. it is not useless.
http://www.youtube.com/watch?v=UBQ5a7mCpMs
good luck trying to get the nobel committee to award any kind of prize for this work, though.
I'm surprised nobody has mentioned the recent string of posts at westhunter about how the mutation rate may be higher in Africa, whether due to the sun (as hbd chick suggests) or because of the average age of fathers.
Also, Steve double-pasted the link to the PC critique.
"But, to Ashraf and Galor, Bolivia _has_ to be the most homogeneous because it’s just about the hardest place to walk to from the Olduvai Gorge. You have to get out of Africa, then you have to get out Siberia, then you have to get past the Panamanian isthmus, then you have to climb high into the Andes. I’m tired just typing all that."
Love it.
A kind of "Eureka complex" has
been too much in evidence over the
last 30 years or more re human origins and migratory patters. The raw fact is that what we yet need to know dwarfs what we do know and many arrogantly discarded notions need to be brought back-- if held in abeyance. The work of Carleton Coon may be one such element due for humble re-view, if
necessarily somewhat re-formed.?
Steve writes: “So, that’s how Bolivia comes out genetically most homogeneous in their study. To you and me, Bolivians may look pretty genetically diverse, with major contributions from Europe and the indigenes, with maybe some African in there in the lowland. But, to Ashraf and Galor, Bolivia _has_ to be the most homogeneous because it’s just about the hardest place to walk to from the Olduvai Gorge. You have to get out of Africa, then you have to get out Siberia, then you have to get past the Panamanian isthmus, then you have to climb high into the Andes. I’m tired just typing all that.”
Steve. The index of diversity is constructed differently and it appears to me perfectly appropriate. As the authors states: “Moving to the contemporary period, the analysis, as discussed earlier, constructs an index of genetic diversity at the country level that not only incorporates the expected heterozygosities of the precolonial ancestral populations of contemporary subnational groups, as predicted by the migratory distances of the ancestral populations from East Africa, but also incorporates the pairwise genetic distances between these ancestral populations, as predicted by their pairwise migratory distances. Indeed, the serial founder effect studied by population geneticists not only predicts that expected heterozygosity declines with increasing distance along migratory paths from East Africa but also that the genetic distance between any two populations will be larger the greater the migratory distance between them.”
Since genetic diversity among Native Americans is the lowest in the world. It seems likely that Bolivia, having one of the largest representation of amerindians has the lowest level of diversity.”
Prof. Robert Sapolsky of Stanford U has a large series of introductory lectures on Human Behavioral Biology that mention very recent research on genes and behavior, including the fact that 'junk' DNA actually performs all kinds of functions. The lectures are from 2010. Start here:
http://www.youtube.com/watch?v=NNnIGh9g6fA&feature=relmfu
Excellent analysis, Steve.
Amish?
They have to be fairly homogenous.
Anyway, their genes are worth a look if for nothing more than a benchmark of what actually happens when 2000 people stew in their own juice for 200 years.
"Before Industrialization, take say 1400, China was quite uniform, and had the highest standard of living and greatest GDP such as it was. Europe was more genetically diverse (and linguistically, and politically); and was lower than China." - Not necessarily, Europe in 1200 AD had around a GDP per capita of around 800-1000$ in 1990's dollars, while China was around 600$.
"British Economic Growth 1270-1870" is the name of the paper where they found this.
"The Chinese invented gunpowder, very good for killing people like your enemies, but did nothing with it. " - Here again, they didn't invent it was we know it. Europeans refined gunpowder through the process of corning, which allowed much more powerful gunpowder, made it safer to work with, and made it safer to work with lots of it(which in turn made things a lot more dangerous for everyone else). Had the chinese figured out corning(which I think was originally an agricultural process used in Europe for something) they probably would have used more of the stuff.
- Not necessarily, Europe in 1200 AD had around a GDP per capita of around 800-1000$ in 1990's dollars, while China was around 600$.
"British Economic Growth 1270-1870" is the name of the paper where they found this.
There has been a sustained spurt of historical quantification over the last decade, most of it based on improving and expanding the pioneering work of Angus Maddison (who passed away in 2010). Maddison, an unabashed sinophile, far from finding evidence of historical Chinese economic leadership (at any period) calculated Chinese performance to substantially lag western Europe even during Chinese cultural highpoints.
Recent work by Paolo Malanima, undoubtedly one of the biggest names working in historical quantification, recently argued that Maddison underestimated Roman economic performance. According to Malanima, the greatest per capita output before Dutch growth took off in the latter 17th century was achieved by Rome, specifically the Italian part, a level of some $1100-1200 1990 international dollars, with Italy at some $1400. Then followed a decline during the early middle ages throughout Europe, but Italy was very early on able to claw its way back to those levels and exceed them by 1300AD, a level it maintained for the next two hundred years before going into a decline that lasted until the late 19th century.
In a nutshell:
Near-subsistence agricultural civilization with "low" or non-existent cultural-civilizational attainment: about $400-600 per capita, eg Pre-columbian mesoamerica, iron age eurasian backwaters.
Literate agricultural civilization $750-$1300, eg Babylon, Persia, Islamic empires, middle ages Europe (beside Italy). (These levels fluctuated and weren't reached by all.)
Going back to human genetic diversity, I rather doubt it will have anything definitive or even important to tell us about historical economic performance, simply because other variables are so much more important. It's only when certain institutions are present and certain ideas pervade society that the population's innate capacity come to the fore. At best, genetics can comment on the likelihood of the right institutions being created and the right ideas dominating, but the attempt to describe economic performance during any historical epoch (when so little was understood about economics, remember) as owing to certain genetic influences is probably flawed at the outset.
"Their critics are pretty silly, but Ashraf and Galor screwed up almost exactly the way I figured they did, only maybe even more so: instead of using diversity of junk genes in isolated pre-Columbian tribes like I assumed, they went one step farther and used a measure of migratory distance from the ancient Out of Africa event to come up with a stylized version of how much Out of Africa junk gene diversity there _would_ be if there hadn’t been any post-1492 admixture with Europeans or Africans!"
Steve, you might want to double check this. It would obviously be theoretically useless to argue that the United States has developed a strong economy based on genetic diversity as measured before European migration - even to academics.
Anonymous above may have a point about the index of diversity being constructed differently from your analysis.
There will be confounds on this sort of research, even if they use actual measures of genetic diversity. Successful white societies draw non-Whites, who increase diversity while reducing per capita GDP.
There is some doubt about the wealthiest countries a thousand years ago if one uses the metric of somehow normalized dollars per capita per year.
If, on the other hand, one judges the wealth of cultures by the number of people per culture, there are two clear winners, India and China.
The main thing both of them have going for them is a nitrogen-fixing source of protein, varieties of lentils and other beans for the Indian family of cultures, soybean for the Chinese.
-dlj.
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