My main beef with the Pomeranzian modern economic history literature is that it gets the explanandum wrong. What needs to be explained is not why the world was polarized in 1800, with Europe taking the lead over other core regions of Eurasia (India, China, Japan). But rather why did the world become polarized from the late-nineteenth century onwards. Another misunderstanding relates to latitude, often thought of as a constant conditioner. It is anything but. Latitude, rather effective temperature for which latitude is a good proxy, is a dynamic variable whose conditioning of societal paths has itself been conditioned by technology and knowhow. To wit, it mattered that industrial work could not be performed in low latitude nations with the same intensity as high latitude nations because of the thermal balance equation. A fruitful strategy to towards answering Yali’s question is to ask, What is the history of the latitudinal gradient? When precisely did high latitude nations pull away decisively from low latitude nations?? The answers one obtains are consistent with a very late departure.

Auke Rijpma has developed a panel dataset of an index of composite well-being derived from life expectancy, urbanization rates, stature, maternal mortality and so on. In this dispatch, we’ll look at the evolution of the latitudinal gradient in this measure. The data is obtained from Clio-Infra.

Our task is simple. We project the index onto latitude for each decade from 1820 to 2000 and examine the diachronic or temporal pattern that emerges. That will allow us to establish the fact of Recency. We begin with the slope coefficient. The structural break appears to be 1860-1880. But let’s dig further.

What happens when we control for volatility? The next figure displays the t-Statistics. The structural break in 1860-1880 now appears to be located precisely in 1870.

But how much variation does latitude actually explain? The next figure displays the percentage of variation explained. From 1830-1860, the latitudinal gradient explains around 10 percent of the variation. That jumps to 25 percent in 1870. It continues to rise intermittently to 40 percent in 1980. That’s the full hockey-stick right there.

Again, let me emphasize that this is merely the explanandum. We have established the fact of a structural break in polarization along latitude around 1870. What is required is a compelling account of how and why this obtained then. And most importantly, why the Industrial Revolution failed to spread beyond the northern core. We can’t do that if we obsess over the British textile boom in 1760-1830. It is time to abandon Whiggish discourses of British self-congratulation.

Postscript. We can also test the Matthew Effect. (“For unto every one that hath shall be given, and he shall have abundance: but from him that hath not shall be taken away even that which he hath.”) We simply project change in the wellbeing index during a decade onto the level of well being at the beginning of the decade. Positive values denote divergence (the already well-off becoming even more well-off relative to the less well-off) while negative values denote convergence.

The pattern that emerges is very interesting. The coefficient is extremely unstable in the ancien regime, ie until the structural break in 1870. In that decade the Great Divergence begins. There are three major waves of divergence: turn of the century, interwar, and postwar. Divergence stops in its tracks after 1980. That’s a very tight representation of the hockey-stick and the attendant divergence in everyday living standards between the core and periphery of the modern world economy.

Advances in genomics in the late-twentieth century inflated an expectations bubble. DNA was supposed to solve all medical problems before long and locate the real, molecular sources of human behavioral variability. DNA has been mobilized to answer Yali’s question — “Why is it that you white people developed so much cargo … but we black people had little cargo of our own?” If one wants to be strict about Mendelian genetics we can date it precisely at the turn of the century with the rediscovery of Mendel’s work in 1900. But appealing to biological reductionism to answer Yali’s question goes back to at least the early nineteenth century. (More on that soon.)

The most refined, if somewhat esoteric, recent attempt may be found in Gregory Clark’s A Farewell to Alms. Clark posits that the reason why the Industrial Revolution began in England (not true) was because the upper classes, who had more industrious, patient, disciplined, ie more bourgeois, genotypes, were more fecund than the lower classes (with their inferior genotypes). He literally has equations to track the slow regression to the mean of all the world’s upper class genotypes and tries to show that such sustained differential fecundity or differential survival of types did not happen elsewhere until much later. He never bothers to motivate the extremely polarized initial conditions — the Normans had to have been extraordinarily superior genotypes relative to the Anglo-Saxons (the Angles and the Saxons, or whatever you want to call the biological populations of England at the time) at the time of the Conquest in 1066 if a thousand years of regression to the mean has not eliminated their naturally higher rates of getting into Oxbridge and leaving large estates. In other words, Clark is the most refined neoracialist of the day: ‘the natural hierarchy of the races’ is posited as the controlling initial condition, since the rest follows from differential fecundity and survival.

An even more sophisticated sleight of hand may be found in the work of Galor and Maov; published, astonishingly enough, in American Economic Review. Here, ‘the natural hierarchy of the races’ is folded into the second moment — what explains global polarization is a quadratic or hump-shaped relationship between ethnogenetic diversity and economic potential. Societies with too much diversity are often dysfunctional; societies with too little genetic variability often fail to produce real breakthroughs except once in a blue moon; in the Goldilocks zone of genetic diversity we find the most advanced societies, the most innovation and all the other goodies economists love. There may be some truth to the matter. Ethnic diversity may indeed condition societal paths. But whether this is the controlling variable is hard to decide. Are high latitudes already privileged over low latitudes (with their high tropical diversity) and their Goldilocks diversity compounds or adds to their privilege, or does diversity trump latitude? They have established the former by showing that the partial correlation coefficients are significant after controlling for latitude (and a slew of other conditioners). They can hardly be expected to establish the latter for latitude itself controls diversity, and exceptions working against the grain of the Heliocentric geometry of our life world are few and far between.

The question of whether mere code is a good place to place causal vectors in human evolutionary biology is rarely posed. To be sure, we can explain certain patterns in physical characters and archeological assemblages etc by mobilizing population history (eg, depigmentation in northern Indians reflects their northern origin, as does the fact that they speak Indo-European). And molecular anthropology has a fine-scale resolution on population history. But even population history merely moves the explanandum to the initial conditions; we need to explain the initial conditions themselves by appealing to deeper principles (respectively, Gloger’s rule is why northern Indians are relatively more depigmented than southern Indians; Indo-Europeans descend from a people whose ethnogenesis was triggered by the introduction of advanced Sumerian technology in the steppe c. 5ka).

Genetics may prove useless to solve disease or explain phenotypic variation but molecular anthropology can certainly do phylogenetics. It is so good that other physical anthropologists test the phylogenetic signal of traditional trackers (craniometric and craniodental metrics, nonmetric cranial and dental polymorphism frequencies, slower-moving postcranial variables and so on) against molecular evidence; as indeed I have been doing without explanation.

But the fact that we have fine-scale or high-dimensional data does not land the causal structure of the world in our lap. It is the explanandum; not the explanation. More generally, DNA, brain scan and surveillance data, what we have is the curse of high-dimensional, fine-scale data that one can interrogate with machine learning algorithms. But Google can never predict whether I will have soup or salad with my lunch tomorrow; at the very least Google is forbidden from telling me the prediction (say soup) for then I can say, screw you Google, today I will have salad just to fuck with you. Not just ego but every awake human is capable of doing the exact same thing to Google. (We should make Google tell people its everyday predictions to screw with their predictive algos!)

To say that something is under genetic control, as I said about pelvic bone width and femur head diameter, is merely to place the explanandum at a specific level of analysis; in the realm of evolutionary biology and really slow-moving climatic and social transformations. In other words, it is just a genetic representation of systematic phenotypic variability that can then be explained though logics of bottlenecks, founder effects, population history, and selection. Put another way, Mary’s genes may explain her wide hips, but the fact that Europeans populations have wider hips requires explanation at a different level of analysis. A satisfactory explanation would reduce the specific explanandum of European pelvic bone widths to the general logic of body size for (say) our genus, order or kingdom.

So we can say that there has been strong selection in the genus Homo for bigger bodies and bigger brains constrained by recoverable secondary productivity, fertility rates, packing thresholds, and labor productivity. Put bluntly, hominins could afford their more energetically expensive bodies for any length of time only when sufficient protein was recoverable from the environment given the state of knowhow/level of foraging productivity, fertility rates and packing thresholds did not bind in the Malthusian sense, epidemiological burdens were light enough to allow high net nutritional standards, and natural selection continued to favor bigger bodies. We know that bigger bodies are still under selection for any reduction in health insults in any human population results in bigger bodies. This implies that the explanation of the Early modern collapse in body size in 1450-1650 must be sought in sharply reduced living standards (ie lower net nutritional status) that may themselves be  explained by say climate stress, epidemiology, war and societal instability.

Whatever the cause of the reduction, the reference frame we are working with allows us to establish the fact of an Early modern catastrophe that can be read off European phenotypes (and maybe genotypes some day). That this fact could be read off the genetic code is not explained by Mendelian laws. The notion that it is so is based on a misunderstanding of the role of the Mendelian component of the tripartite modern evolutionary synthesis. (The other components are natural history and natural selection.)

So, we may take the evidence we have marshalled as proof against the refined neoracialism of Gregory Clark. He has established that the upper classes were taller, bigger, and more fecund than the lower classes in England in the centuries after the Conquest. But the inference that English and European genotypes converged over time to the upper class genotype through this process is not borne out by European phenotypes which deteriorated sharply in the crucial phase at issue, 1450-1700 CE. For if he was right, we should expect the opposite movement in the slowest moving variables from what we see: European pelvic bone width should increase after the Medieval period.

Boasian antiracists know that there is a short step from worship of genes to worship of race. But they have failed to articulate the precise problem with biological reductionism. The problem lies in conflating levels of analysis. What looks like an explanation at the level of the individual or cohort, is the explanandum at the level of populations over many generations. To wit, DNA is just code. To say that vertical or global polarization (ie the differential economic performance of populations) is due to genetic differences — ie racialism as a scientific hypothesis — is at best like saying that rich Americans face lower tax burdens than their secretaries because of specific articles in the tax code. It is simply the wrong level of analysis — for a more satisfactory explanation of differential tax burdens we need an account of American political economy. Likewise, even if it can be shown that something is under genetic control, we still need an account of why the genetic code says what it does. And that takes us straight back across the Nature-Society dichotomy.

I owe a better, more general, explanation of the level of analysis problem to J. Dmitri Gallow. Think of a pole in a field whose shadow lands on May 14 on every year at a specific position where a stone has been in place since the pole was erected. A reductionist explanation would be: Here are the laws of optics, here’s the height of the pole and the distance to the stone, here’s the position of the sun that time of the year. One can seemingly hardly argue with the reductionist account. But wait. What if I told you that the pole was erected by Mr. Dawson because his wife came to grief precisely where the stone now sits on May 14, 1947, and that Dawson erected the pole to do precisely what it does every year on that sad day (in obedience to the laws of optics) precisely to commemorate the day she came to grief? That changes everything. The reductionist account turns out to be actively misleading in discerning the chain of causation for it turns out that human agency was the cause of the fact we were seeking to explain; that the nuts and gears of the reductionist account were involved in merely passive proximate processes.

A more fundamental critique of racialism and the self-congratulation of molecular anthropology must begin with the fundamental insights of Boas and Chomsky. The key observation is that the language faculty is exclusive to our species and uniform across it. To wit, a Japanese child growing up in Bengal would speak Bengali like a native. That can only be if the capacity for generative grammar (ie the capacity to generate a countable infinity of structured sentences from a finite lexicon) is truly universal across our species — and by implication under the tightest genetic control. The import is intellectually and politically radical: The Boasian universal — all hunter-gatherers were found without a single exception to have music, dancing, gossip, mythology, ritual, foraging expertise, and the full package of the drama of human life — trumps whatever minor systematic differences exist between populations. Put bluntly, not only the Romans and not only us moderns, but all societies of fully modern humans (ie endowed with the Boasian universal), whether they had high civilization or not, can identify with Greek drama. For even if we admit genetic disadvantages as handicaps, it may be retorted that even a severely handicapped person may turn out to make extraordinary contributions to the human project — think of Stephen Hawking. The human universal thus furnishes a powerful weapon against biological reductionism and the politics of biological differences.

We gotta cut molecular anthropology down to size. If only to get a better handle on physical anthropology, and ultimately, to make progress in answering Yali’s question.

Part of the problem with modern scholarly discourses on global polarization is that they get the explanandum wrong. Contrary to the emplotment of modern economic historians, global polarization did not begin with the Industrial Revolution. More precisely, the latitudinal gradient in living standards became steeper in the century after 1870 as high latitude nations pulled away from low latitude nations. But the gradient already existed before the nineteenth century. When did it come into existence? I will show that it has always existed; that high latitudes have been favored for at least forty thousand years.

No matter what numbers are being thrown around, we do not have data on effective incomes going back more than a few centuries. And even the national economic statistics that we do have are not entirely reliable. Much more reliable are actuarial measures like life expectancy. But these too aren’t available beyond a few centuries. We have no choice but to rely on anthropometric measures like stature and body size. Fortunately, these are faithful indicators of living standards, particularly when averaged over long periods. The reason is very simple. Whether or not there were Malthusian cycles before the breakthrough to industrial modernity, long run differences in height and body size between chrono-demes indicate differences in net nutritional status (otherwise they couldn’t possibly last for so long). This true both diachronically and synchronically; that is, it holds across the panel data. We’ll focus on the former in this dispatch. But we’ll get the latter out of the way first.

We will interrogate variables from the Ruff et al. (2018)’s osteometric dataset that are known to correlated with everyday living standards from modern data. Table 1 reports the estimates. The latitudinal gradient is estimated by OLS after controlling for fixed effects for sex and period. We can see that it is extremely significant for all variables except pelvic bone width (which may have to do with small sample sizes for specific periods). Note that this is within Europe. Across the globe the tyranny of the isotherms is even more manifest. The parameter estimates for the dummies in Table 1 measure how much the periods diverge from the Bronze Age.

The following tables report the means for the periods.

The basic pattern is hard to escape. Pre-LGM populations were bigger and taller than populations at the other end of the great bottleneck associated with the Last Glacial Maximum. The decline between the Early and Late Upper Paleolithic is highly significant. During the Neolithic, Europe saw the arrival of slightly taller but otherwise smaller populations of farmers from the Near East. This is expected since height is more plastic than other measures of body size and these populations were adapted to the warmer climes (and thus smaller in accordance with Bergmann’s rule). The same biological populations survived into the Bronze Age. Appropriately, we see little change between the Neolithic and the Bronze Age. Although female pelvic bone width does widen. The Iron/Roman period is after the arrival of the Yamnaya pastoralists. These were bigger people but not so wide at the hips. Stature increased between the Iron Age and the Medieval Age, but only for males. Body mass barely increased. There was a major fall in living standards in the early modern transition. Was this related to the epidemiological unification of the world or the transition to urban life? At any rate what is clear is that there was a severe decline in living standards between the Medieval and the Early Modern eras. In the last transition, that between Early Modern and Modern eras, we see that male living standards improved but female living standards did not. But we should note that male measures are more reliable since some basic parameters of female skeletons, especially pelvic bone width, may be more plastic due to the rapid feedback from maternal mortality. 

So I was not kidding about it being downhill since the days of the Gravettian mammoth hunters. Do not miss the force of the argument. Averaged over thousands or hundreds of years, anthropometric metrics like stature and body mass contain a very strong signal of living standards. The big picture is clear from the index displayed next. It adds up the values of femur maximum length, pelvic bone with and femur head diameter after standardizing them to have mean 0 and variance 1 (and adding 100 to the result). It could not be clearer that pre-LGM populations were dramatically bigger than later Europeans; that there was a significant shrinking of European body size between 1450 and 1720 CE, followed by a significant improvement in the last 100 years or so.

The notion that European living standards were stuck in a Malthusian trap is inconsistent with the evidence marshalled here. The evidence indicates that European nutritional standards were higher for two thousand years before 1450, when they began to decline, not to improve until the late-nineteenth century. Is the Malthusian Trap a real thing or a phantasmagoria of economic historians seeking a structural break on the wrong side of 1800? And what on earth were the Gravettians eating? (Ha.)

Because Europeans have been obsessed with ‘the races of Europe’ — the title of Ripley (1899); later echoed by Coon (1939) — and craniologists prevailed against philologists in identifying them after the professionalization of science in the late-nineteenth century, all human taxa (specific and subspecific) are still identified through craniology. This is as it should be since there is a stronger population history signal in craniometrics relative to linguistics (although the strongest population history signal is in dental polymorphisms). However, what physical anthropology (molecular or otherwise) of the living can tell us is the phylogenetic relationship of living populations. It cannot tell us about population history, or about the histories of vanished paleo-demes. For that we need molecular or cranial paleontology. That is, we need fossils.

Contemporary populations of European ancestry are admixtures of Yamnaya pastoralists who arrived from the steppe 5ka and Neolithic farmers who arrived from the Near East around 9ka. Reich et al. assumed that under these Neolithic populations was a uniform substratum of Upper Paleolithic hunter gatherers presumably descended from the Cro-Magnons, although they did distinguish between western and eastern paleo-demes.

That presumption turns out to have been badly wrong. The reason is that the great ice age that lasted from 30-20ka — the last glacial maximum (LGM) is dated to 26ka — generated a very severe population bottleneck. The impact was particularly drastic in Europe where faunal populations, including human demes, became isolated in refugia (largely in southern Europe). The drastic reduction in population size meant a major loss of genetic diversity. For instance, the diagnostic haplogroup for Asians that present-day Europeans do not have, has been found in pre-LGM populations. It was lost during the LGM-bottleneck.

Replicating the work of Brewster et al. (2014), I will show that pre-LGM paleo-demes were physically different from post-LGM paleo-demes. These paleo-demes were the authors of remarkable Upper Paleolithic cultures, particularly the Gravettian. Indeed, the LGM discontinuity is so drastic that we may speak of the vanished civilization of the Gravettian peoples. We’ll look at fossil skeleton metrics for pre-Neolithic paleo-demes in Europe. Unlike Brewster et al. (2014), we’ll distinguish between three chrono-groups: pre-LGM/Early Upper Paleolithic 35-20ka, late glacial/Late Upper Paleolithic 18-10ka, and Holocene/Mesolithic 10-5ka. We’ll label them with the predominant cultures in these sample: Gravettian, Magdalenian, and Mesolithic. All cranial data is from Brewster et al. (2014), and all postcranial data is from Ruff et al. (2018), Skeletal Variation and Adaptations in Europeans: Upper Paleolithic to the Twentieth Century.

We begin with postcranial size variables. There was a steady decline in stature over time. The Gravettians were considerably taller than later paleo-demes.

They also weighed a bit more. Although the t-test is not significant (p=0.152).

Recall that these are allometric estimates. We have much more reliable measures of body size. Femur head diameter and pelvic bone width are not only the main weight carrying parameters of the human skeleton, they are also under tighter genetic control.

Gravettian and Magdalenian femur head diameter and pelvic bone width are not significantly different. However, Gravettian and Mesolithic populations are significantly different by both measures (p=0.078 for femur head diameter and p=0.016 for pelvic bone width).

Gravettian and Magdalenian femur length differences are highly significant (p<0.001). Recall that femur lengths and stature are controlled by net nutritional status. This suggests that the Gravettians had much higher nutritional standards than later paleo-demes.

Moving onto craniometrics, we look first at skull size calculated as the geometric mean of skull length, height, and width. The difference between Gravettian and Magdalenian skull size is not statistically significant (p=0.706). In sum, the Gravettians were taller than Magdalenians but not otherwise bigger. Both were however absolutely bigger than later Mesolithic Europeans.

We now look at cranial variables after adjusting them for skull size. So these are shape variables that contain information largely orthogonal to the size variables we have so far examined. Of the 10 cranial measurements in the Brewster et al. dataset, only in the following four is there a statistically significant difference between the pre-LGM Gravettian and the post-LGM Magdalenian skulls. Gravettian skulls were longer.

Gravettian foreheads were broader.

They had taller noses …

… that we narrower.

Table 1 reports the results of our t-tests for size-adjusted Gravettian-Magdalenian craniometric differences.

Who were these people with long heads, narrow and tall noses, and broad foreheads? Why were they so tall? People have tried to trace the tall stature of contemporary Bosnians to inheritance from this paleo-deme. That patent nonsense for stature is controlled by health insults. Whatever the correlations with haplotype, this variable is just too plastic. Moreover, the genotype of the Gravettians largely vanished in the LGM bottleneck. All later demes, including and especially contemporary populations, inherited little of their genotype. As far as present-day populations of European ancestry are concerned, they might as well be Neanderthals.

But I would go much further. Ancient paleo-demes, particularly pre-LGM ones like the authors of the Gravettian, cannot be projected onto contemporary classifications. Not only do they have different genotypes and different cranial morphologies, they also had different skins and eye colors than contemporary Europeans. For instance, we know that the genetic basis for depigmentation came under selection in Europe only 7ka; while that for blue eyes came under (probably sexual) selection 14ka. We don’t know yet if the Gravettians looked fair or if some of them had blue eyes. Possibly. But if so, it had a different genetic basis from contemporary morphotypes.

What is clear is that they had much higher standards of living than later paleo-demes. Why? The answer is the great mammoth steppe.

Source: Clive Gamble, Settling the Earth.

During the Upper Pleistocene, vast herds of woolly mammoth and other megafauna roamed across the northern Eurasian steppe, extending from the great European plain all the way to north America. How was it possible to sustain such high secondary productivity during the ice ages? As Gamble reports,

The mammoth steppe comes down to a simple observation by zoologist Dale Guthrie – that today’s boreal and tundra vegetation of Beringia could not have supported the large herds of bison, horse, reindeer and above all mammoth whose bones, and sometimes carcasses, are preserved by their millions in its frozen silts. Tundra plants and boreal trees produce a toxic litter that affects the soil, leaving very little for animals to feed on. Furthermore, they act as a blanket so that the level of annual freeze–thaw is small. The factor which changed this balance between plants and soil was the aridity of the Pleistocene. Creating the mammoth steppe depended on high evaporation and a deeper thaw in summer that released nutrients from lower down in the soil. This, according to Guthrie, broke the cycle of low soil nutrients and toxic plants. It produced a richer soil and the conditions for the abundant growth of grass. These grasses were resistant to grazing pressure, grew quickly and formed a rich mosaic of vegetation conditions, likened to the weave in a plaid, and contrasted with the stripes, or bands, of vegetation found in the warmer Holocene. Isotope studies suggest that mammoths consumed higher quantities of dry grass than the other grazers such as reindeer, horse and woolly rhino. The mammoth steppe developed across Western Europe to Beringia during a major glaciation, MIS12, 500ka. It supported a diverse, high-biomass animal community, compared to the present tundra and boreal forests. Besides the major herd animals — mammoths, woolly rhinos, bison, horse, red deer, reindeer, musk ox and saiga antelope — there were major carnivore guilds of lions, hyenas, wolves, leopards and foxes, and omnivores such as bears.

The Gravettian civilization was based on the western extremity of the mammoth steppe. As the mammoth steppe contracted east, the Gravettians moved with it. The west-east movement is very marked in Gravettian sites. While some Gravettian populations specialized in mammoth hunting, the notion that they were all specialized mammoth hunters has been discredited. The Gravettians certainly hunted mammoths — they were probably the first humans to do so — but they also hunted other game. Their kitchen middens display significant variability. They did however collect mammoth bones at scale. They build shelters with them, used them to make all sorts of tools. Mammoth bones very likely also had a religious function in Gravettian civilization. For as Soffer (1993) reported and was recently confirmed for a Russian site, the spatial patterns of Gravettian camp sites suggest that mammoth bones were segregated from those of other animals. 

So the Gravettians not only had a highly distinct morphology (and genotype), they also had a very distinctive way of life that was highly advanced. They were certainly better fed than later populations. We are just beginning to appreciate the ways of life, and indeed, histories, of this ancient civilization.

This foray into the Gravettian mammoth hunters will help us think about combined and uneven development in the Upper Pleistocene. More on that later.