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I just finished reading a review of the literature since 1984 on the bioarchaeology of the transition to agriculture. Stature and robusticity during the agricultural transition: Evidence from the bioarchaeological record:

The population explosion that followed the Neolithic revolution was initially explained by improved health experiences for agriculturalists. However, empirical studies of societies shifting subsistence from foraging to primary food production have found evidence for deteriorating health from an increase in infectious and dental disease and a rise in nutritional deficiencies. In Paleopathology at the Origins of Agriculture (Cohen and Armelagos, 1984), this trend towards declining health was observed for 19 of 21 societies undergoing the agricultural transformation. The counterintuitive increase in nutritional diseases resulted from seasonal hunger, reliance on single crops deficient in essential nutrients, crop blights, social inequalities, and trade. In this study, we examined the evidence of stature reduction in studies since 1984 to evaluate if the trend towards decreased health after agricultural transitions remains. The trend towards a decrease in adult height and a general reduction of overall health during times of subsistence change remains valid, with the majority of studies finding stature to decline as the reliance on agriculture increased. The impact of agriculture, accompanied by increasing population density and a rise in infectious disease, was observed to decrease stature in populations from across the entire globe and regardless of the temporal period during which agriculture was adopted, including Europe, Africa, the Middle East, Asia, South America, and North America.

The abstract makes the conclusion more cut & dried than it is. It’s the result of aggregating their literature review and arriving at a net conclusion. Yes, on the balance agriculture did result in the deterioration of health. The old truism that farmers are a small and ill lot in comparison to hunter-gatherers seem to be correct in the generality. But the literature review also makes it clear that when it comes to something like stature there are often periodic reversals of the trend toward decrease in size. There may be spottiness of the record, and sampling error, but I began to wonder if we might not be seeing evidence of evolution & innovation in action!

Consider the checkered history of the potato in Ireland. In the 18th century the Irish shifted toward the potato faster than most other European peoples, and so entered into a phase of massive population expansion. On a per unit basis the potato was nutritional gold. Unfortunately we all know that the blight of the 19th century triggered a series of social and demographic catastrophes.

But, the insight here is that we may have to think of the “transition to agriculture” as a more complex affair. My conceptualization is most easily illustrated by a chart:

First you see the low population-low morbidity stable-state of the hunter-gatherer society. Per unit productivity is low, keeping a check on the maximum carrying capacity. But because populations are dispersed many of the infectious diseases which we take for granted are simply not issues for hunter-gatherer bands. Next you see the transition to agriculture. This increases per unit productivity by a order of magnitude, resulting in a situation of “land surplus.” A huge population explosion follows, and now the stage is set for the rise of infectious diseases. As the population reaches carrying capacity individuals are under nutritional stress. Additionally, the agriculturalists will also no longer have access to game & herbs to supplement their calorie-rich but micronutrient and protein poor diets. They’ve given the land over to raising enough food to maintain their population. Now diseases of mass agriculture begin to spread, and the new farmers have no resistance. Already subject to greater morbidity because of the nature of their diet, they become victims of a pandemic.

In classic Malthusian fashion morbidity abates as population density declines. Additionally, the survivors will now have some immunity to the infectious agents. We are past “peak morbidity.” Evolution also now begins to select individuals who are more well adapted to the rigors and stresses of agricultural life. The population reaches carrying capacity again, but though morbidity is still above the hunter-gatherer stage, it does not hit its previous high.

This does not prevent populations from being beset by “exogenous shocks.” A famine results in a sharp population reduction, but after the environment becomes favorable again the population bounces back. Also, the temporary land surplus benefits the survivors. Despite the power of “endogenous” parameters, there are always going to be periodic random environmental catastrophes or windfalls modulating the population size and average well being.

Finally, a secondary “agricultural revolution” occurs. A new innovation, most likely a superior cultivar or food crop, arrives on the scene. Like the original transition to agriculture you see an immediate per unit increase in productivity. This means that there is a practical land surplus. Because the population is now “catching up” to its carrying capacity the morbidity drops again. What happened in Ireland in the 18th century, or in China after the “Columbian Exchange,” may be modeled by this phenomenon. Finally the population is at a new higher carrying capacity.

Even this is simplified. But I think it takes into account the reality that both biology and culture evolve. And it may explain some of the shifts outside of the standard Malthusian economic model, which assumes a relatively static technological environment.

• Category: Science • Tags: Agriculture, Anthropology, Culture, Farming 
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A new paper in Proceedings of the Royal Society dovetails with some posts I’ve put up on the peopling of Japan of late. The paper is Bayesian phylogenetic analysis supports an agricultural origin of Japonic languages:

Languages, like genes, evolve by a process of descent with modification. This striking similarity between biological and linguistic evolution allows us to apply phylogenetic methods to explore how languages, as well as the people who speak them, are related to one another through evolutionary history. Language phylogenies constructed with lexical data have so far revealed population expansions of Austronesian, Indo-European and Bantu speakers. However, how robustly a phylogenetic approach can chart the history of language evolution and what language phylogenies reveal about human prehistory must be investigated more thoroughly on a global scale. Here we report a phylogeny of 59 Japonic languages and dialects. We used this phylogeny to estimate time depth of its root and compared it with the time suggested by an agricultural expansion scenario for Japanese origin. In agreement with the scenario, our results indicate that Japonic languages descended from a common ancestor approximately 2182 years ago. Together with archaeological and biological evidence, our results suggest that the first farmers of Japan had a profound impact on the origins of both people and languages. On a broader level, our results are consistent with a theory that agricultural expansion is the principal factor for shaping global linguistic diversity.

I don’t know the technical details of linguistics to comment, but the alignment between the linguistic model and archeology is pretty impressive to me. There’s a 95% confidence interval which can push the time back to 4,000 years, so there’s some fudge factor too. The basic technique is borrowed from phylogenetics. This is pretty clear when you notice that one of the algorithms seems to be the same one used in the rice genomics paper. Nick Wade covers the paper in The New York Times, so no need for me to give a blow-by-blow in a domain where I don’t have much insight anyway.

Dienekes Pontikos really likes these results and the method which they use. He, rightly in my opinion, believes that they lend more credence to the thesis promoted in the early 2000s using the same technique that the last common ancestor of Indo-European languages is very far back in time. I’m skeptical of this model, at least in its simple general form, but these results do push me into thinking that that model is more plausible. But to really understand this stuff I probably need to teach myself some rudimentary linguistics, so I guess we’ll see.

More broadly this gets to the question: did farming spread through demographic expansion or cultural diffusion? Obviously it’s not an either/or. There’s a small residual of Amerindian ancestry in American whites, so there was some diffusion through genetic assimilation. The Xhosa tribe of South Africa seem to have ~20% Khoisan ancestry. They’re the group on the Bantu farming frontier, the last before the Bantu toolkit ceased to be effective and the Khoisan managed to maintain their hold before the whites arrived. Some of the admixture is from pastoralist Khoi, but some of it may also be from hunter-gatherer Bushmen. But here’s my issue at this point: what are the examples where we know that hunter-gatherers picked up agriculture? The instances of Japan and the Bantu expansion are two where we’re now rather sure that it was demographic expansion and replacement. Was it so different in the past? I think it may have been insofar as farming was less advanced a cultural toolkit in terms of its ability to overpower hunter-gatherers. And yet still I am becoming more convinced of the thesis of that farming spread through procreation, not propagation. My hesitation is mostly due to the reality that our understanding of the past is so clouded as a fundamental matter.

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The economist Samuel Bowles recently had a paper out in PNAS which caught my attention, Cultivation of cereals by the first farmers was not more productive than foraging. This naturally begs the question: why did farming conquer foraging as a lifestyle? First, let’s look at the abstract:

Did foragers become farmers because cultivation of crops was simply a better way to make a living? If so, what is arguably the greatest ever revolution in human livelihoods is readily explained. To answer the question, I estimate the caloric returns per hour of labor devoted to foraging wild species and cultivating the cereals exploited by the first farmers, using data on foragers and land-abundant hand-tool farmers in the ethnographic and historical record, as well as archaeological evidence. A convincing answer must account not only for the work of foraging and cultivation but also for storage, processing, and other indirect labor, and for the costs associated with the delayed nature of agricultural production and the greater exposure to risk of those whose livelihoods depended on a few cultivars rather than a larger number of wild species. Notwithstanding the considerable uncertainty to which these estimates inevitably are subject, the evidence is inconsistent with the hypothesis that the productivity of the first farmers exceeded that of early Holocene foragers. Social and demographic aspects of farming, rather than its productivity, may have been essential to its emergence and spread. Prominent among these aspects may have been the contribution of farming to population growth and to military prowess, both promoting the spread of farming as a livelihood.

My own working assumption is that the “first farmers” existed in a state of land surplus, and so like the medieval peasants in the wake of the Black Death found themselves released from Malthusian constraints, at least until their natural increase swallowed up their affluence. Bowles gives several reasons to be skeptical of this conjecture. The list in table 2 shows the positive and negative biases in the model when one back-projects later stages of farming to the initial period. Metal tools, well developed distribution channels, and more productive varieties, were features of mature agricultural societies. On the time-insensitive scale the necessity of planning ahead and waiting patiently for the crop to be ripe count against the gains of the farming way of life as well. The main variable which would weight in favor of farming is the land surplus alone, though Bowels argues that the ethnographic data as to the benefits of a surfeit of this input factor of production is mixed. I am skeptical of this point, though I can’t say I’ve dug deeply into the literature.

There are other factors, such as the fact that farmers were immobile, and so subject to attack. A shift toward a few crops also reduced the diversity of the diet, and therefore entailed a trade off between a diet rich in micronutrients, fiber, protein, and fat, to one overloaded on carbohydrates. Finally, a reliance on a few crops also means heightened “tail risk.” Think of the Irish potato blight. Hunter-gatherer populations would usually have a more diverse portfolio, and so be buffered more from environmental shocks.

One thing to add though is that the productivity of farming vs. foraging differs on the margin. Farming as a complement to foraging can be highly productive, as one substitutes labor hours devoted to low gain foraging to high gain farming. The key is that as farming comes to be the dominant strategy the low hanging fruit is picked, and one has to squeeze the same, or less, production out of a greater number of hours. So why farming and not foraging? I find Bowels conclusion rather cryptic:

However, an evolutionary argument may be able explain the eventual spread of farming once it was adopted in a few places. Because of extraordinary spatial and temporal variations in weather, soil quality, scarcity of wild species, and other conditions that could make farming rather than foraging an efficient provisioning strategy, it is likely that a few groups would have found it advantageous (by the marginal conditions above) to take up farming as their primary livelihood. Then, in order for farming subsequently to be adopted by other groups—the evolutionary problem—farming need not have lessened the toil of subsistence. Even if health status and stature declined, the lesser mobility of farmers would have lowered the costs of child rearing (41). This lowering could have contributed to the dramatic increase in population associated with cultivation (7) and, hence, to the spread of farming (12). Or the fact that agricultural wealth (stored goods and livestock particularly) was more subject to looting may have induced farming groups to invest more heavily in arms and to exploit their greater population densities, allowing them to encroach on and eventually replace neighboring groups (11).

I think this suggests is that farming vs. foraging is a tale of quantity vs. quality. But well mobilized quantity can be quality. The disciplined phalanxes of ancient Greece and the legions of Rome were those of peasant farmers. They may have been relatively lacking in meat and milk, and therefore muscle, in comparison to aristocratic Gaulish and Persian levies, but they made up for it in cohesiveness of collective action and singularity of political purpose. The static immobility and density of farmers may have made them more susceptible to the institutions and ideology which bind a society together, and so allowed a group of villages to operate almost as an organismic whole. Against this mass action the forager clans, effective as individual units, but unable to coordinate, may have been impotent.

Therefore, the rise of farming may have been accompanied by the first demagogues and the blitzkrieg.

• Category: Science • Tags: Anthropology, Culture, Farming, Neolithic Revolution 
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After linking to Marnie Dunsmore’s blog on the Neolithic expansion, and reading Peter Bellwood’s First Farmers, I’ve been thinking a bit on how we might integrate some models of the rise and spread of agriculture with the new genomic findings. Bellwood’s thesis basically seems to be that the contemporary world pattern of expansive macro-language families (e.g., Indo-European, Sino-Tibetan, Afro-Asiatic, etc.) are shadows of the rapid demographic expansions in prehistory of farmers. In particular, hoe-farmers rapidly pushing into virgin lands. First Farmers was published in 2005, and so it had access mostly to mtDNA and Y chromosomal studies. Today we have a richer data set, from hundreds of thousands of markers per person, to mtDNA and Y chromosomal results from ancient DNA. I would argue that the new findings tend to reinforce the plausibility of Bellwood’s thesis somewhat.

The primary datum I want to enter into the record in this post, which was news to me, is this: the island of Cyprus seems to have been first settled (at least in anything but trivial numbers) by Neolithic populations from mainland Southwest Asia.* In fact, the first farmers in Cyprus perfectly replicated the physical culture of the nearby mainland in toto. This implies that the genetic heritage of modern Cypriots is probably attributable in the whole to expansions of farmers from Southwest Asia. With this in mind let’s look at Dienekes’ Dodecad results at K = 10 for Eurasian populations (I’ve reedited a bit):


Modern Cypriots exhibit genetic signatures which shake out into three putative ancestral groups. West Asian, which is modal in the Caucasus region. South European, modal in Sardinia. And Southwest Asian, which is modal in the Arabian peninsula. Cypriots basically look like Syrians, but with less Southwest Asian, more balance between West Asian and South European, and far less of the minor components of ancestry.

Just because an island was settled by one group of farmers, it does not mean that subsequent invasions or migrations could not have an impact. The indigenous tribes of Taiwan seem to be the original agriculturalists of that island, and after their settlement there were thousands of years of gradual and continuous cultural change in situ. But within the last 300 years settlers from Fujian on the Chinese mainland have demographically overwhelmed the native Taiwanese peoples.

During the Bronze Age it seems Cyprus was part of the Near East political and cultural system. The notional kings of Cyprus had close diplomatic relations with the pharaohs of Egypt. But between the end of the Bronze Age and the Classical Age Cyprus became part of the Greek cultural zone. Despite centuries of Latin and Ottoman rule, it has remained so, albeit with a prominent Turkish minority.

One thing notable about Cyprus, and which distinguishes it from mainland Greece, is the near total absence of a Northern European ancestral component. Therefore we can make the banal inference that Northern Europeans were not initially associated with the demographic expansions of farmers from the Middle East. Rather, I want to focus on the West Asian and Southern European ancestral components. One model for the re-population of Europe after the last Ice Age is that hunter-gatherers expanded from the peninsular “refugia” of Iberia and Italy, later being overlain by expansions of farmers from the Middle East, and perhaps Indo-Europeans from the Pontic steppe. I have a sneaking suspicion though that what we’re seeing among Mediterranean populations are several waves of expansion out of the Near East. I now would offer the tentative hypothesis that the South European ancestral element at K = 10 is a signature of the first wave of farmers which issued out of the Near East. The West Asians were a subsequent wave. I assume that the two groups must correlate to some sort of cultural or technological shift, though I have no hypothesis as to that.

From the above assertions, it is clear that I believe modern Sardinians are descendants of that first wave of farmers, unaffected by later demographic perturbations. I believe that Basques then are a people who emerge from an amalgamation of the same wave of seafaring agriculturalists with the indigenous populations preceding them (the indigenes were likely the descendants of a broad group of northern Eurasians who expanded after the end of the last Ice Age from the aforementioned refugia). They leap-frogged across fertile regions of the Mediterranean and pushed up valleys of southern France, and out of the Straits of Gibraltar. Interestingly, the Basque lack the West Asian minority element evident in Dienekes’ Spaniards, Portuguese, as well as the HGDP French (even up to K = 15 they don’t shake out as anything but a two way admixture, while the Sardinians show a minor West Asian component). Also, the West Asian and Southern European elements are several times more well represented proportionally among Scandinavians than Finns. The Southern European element is not found among the Uyghur, though the Northern European and West Asian one is. I infer from all these patterns that the Southern European element derived from pre-Indo-European farmers who pushed west from the Near East. It is the second largest component across much of the Northwestern Europe, the largest across much of Southern European, including Greece.

A second issue which First Farmers clarified are differences between the spread of agriculture from the Near East to Europe and South Asia. It seems that the spread of agriculture across South Asia was more gradual, or least had a longer pause, than in Europe. A clear West Asian transplanted culture arrived in what is today Pakistan ~9,000 years ago. But it does not seem that the Neolithic arrived to the far south of India until ~4,000 years ago. I think that a period of “incubation” in the northwest part of the subcontinent explains the putative hybridization between “Ancient North Indians” and “Ancient South Indians” described in Reconstructing Indian population history. The high proportion of “Ancestral North Indian,” on the order of ~40%, as well as Y chromosomal markers such as R1a1a, among South Indian tribal populations, is a function of the fact that these groups are themselves secondary amalgamations between shifting cultivators expanding from the Northwest along with local resident hunter-gatherer groups which were related to the ASI which the original West Asian agriculturalists encountered and assimilated in ancient Pakistan (Pathans are ~25% ASI). I believe that the Dravidian languages arrived from the Northwest to the south of India only within the last 4-5,000 with the farmers (some of whom may have reverted to facultative hunter-gathering, as is common among tribals). This relatively late arrival of Dravidian speaking groups explains why Sri Lanka has an Indo-European presence to my mind; the island was probably only lightly settled by farming Dravidian speakers, if at all, allowing Indo-European speakers from Gujarat and Sindh to leap-frog and quickly replace the native Veddas, who were hunter-gatherers.

Note: Here is K = 15.

* Wikipedia says there were hunter-gatherers, but even here the numbers were likely very small.

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A new paper in The New Journal of Physics shows that a relatively simple mathematical model can explain the rate of expansion of agriculture across Europe, Anisotropic dispersion, space competition and the slowdown of the Neolithic transition:

The front speed of the Neolithic (farmer) spread in Europe decreased as it reached Northern latitudes, where the Mesolithic (hunter-gatherer) population density was higher. Here, we describe a reaction–diffusion model with (i) an anisotropic dispersion kernel depending on the Mesolithic population density gradient and (ii) a modified population growth equation. Both effects are related to the space available for the Neolithic population. The model is able to explain the slowdown of the Neolithic front as observed from archaeological data

The paper is open access, so if you want more of this:

Just click through above. Rather, I am curious more about their nice visualization of the archaeological data:


Note how much variance there is in terms of the rate of change of the clines. As I’ve observed before there was a “break out” of the LBK farmers into Central Europe nearly 7,000 years ago, but it took much longer to close the gap between the farms on the frontier and the sea. This is well known from the archaeology, as there seems to have been a pause of ~1,000 years across much of the north European plain. On the scale of 10,000 years that’s not much time, but that’s about 40 generations. In Frisia it looks like the spreading of farming stopped for nearly ~2000 years!

Why the abatement of the spread of farming? I think the authors of the above paper are correct in their acceptance of the conventional wisdom of greater Mesolithic densities in Northern Europe. But I think perhaps a better description might be maritime Northern Europe. We often imagine early farmers displacing hunters and gatherers of game and herb, but what if in much of the world the main clash numerically was between dense populations oriented toward the sea, and those who were depended on the land? About seven years ago a study came out which argued for a rapid transition from seafood to meat in the diets of early Britons, Why Did Ancient Britons Stop Eating Fish?:

When cattle, sheep, pigs, and wheat arrived on the shores of Great Britain about 5,000 years ago, fish quickly fell off the Neolithic menu, according to an analysis of human bones scattered throughout the island.

“Farming really took off in Britain during the Neolithic. The main questions concerning the speed of change relates to how quickly Mesolithic peoples adapted—or otherwise—to the new farming methods and/or the spread of farming into Britain by new farming communities,” he said.

The research by Richards and colleagues Rick Schulting at Queen’s University Belfast and Robert Hedges at the University of Oxford tracks the shift in diet by examining the dietary signature stored in the bones.

They find that the shift was rapid and complete at the onset of the Neolithic. “Marine foods, for whatever reason, seem to have been comprehensively abandoned,” the researchers conclude in the September 25 issue of the journal Nature.

“We determined that after the introduction of domesticates, as well as the other artifacts associated with the Neolithic, the isotope values showed that marine foods were not used anymore,” he said. “We then infer that this is a switch from wild foods such as fish and shellfish to the new domesticates that arrive at this time.”

Richards said there are three plausible reasons why the British abandoned seafood from the beginning of the Neolithic: the domesticated plants and animals presented a steady source of food; the shift was forced by a climate change; or cultural pressure.

In the early 2000s the idea of wholesale rapid demographic replacement was not in the air. I think we need to put that back on the table. Here is the chart on isotope ratios from the 2003 paper:

Notice the sharp discontinuity. Richards et al. in 2003 interpreted this as a rapid cultural acquisition of the Neolithic lifestyle ~2500-3000 BC. They note in the media reports that later Britons, for example at the time of the Roman conquest, seem to have utilized fish a bit more in their diet than these early Neolithics. This stands to reason, much of Britain is not too far from the sea. To me the very sharp drop in marine consumption is indicative more of a food taboo, than a practical shift. Obviously farmers would primarily be subsistent on grain, but there’s no necessary reason to avoid meat or fish, but as it happens in many parts of the world societies preserve and perpetuate exactly such norms. These norms may have spread through cultural diffusion, for example through an adoption of a new religion. Or, the norms may have been brought by a new group which arrived in large numbers and replaced the indigenous population.

Here is an equivalent chart from Denmark from an earlier paper by the same group:


800px-Saami_Family_1900pacnortWhen we think of peoples who aren’t farmers, we often think of marginalized nomadic or semi-nomadic groups. Many of the remaining hunter-gatherers such as Bushmen, as well societies which supplement their conventional lifestyle with a lot of hunting & gathering, such as the indigenous peoples of Siberia or the Sami of northern Scandinavia, occupy territory which is simply not viable for conventional agriculture. But this was not so in the past. Before the farmers arrived the rich bottom-lands were occupied by hunters & gatherers, of fish, game, grain, and nuts. In certain ecologies, such as around productive estuaries one could imagine enormous aggregations of these peoples. Additionally, it seems likely that a sedentary lifestyle predates farming. A good contemporary analog for what ancient Northern Europe may have been like was the Pacific Northwest before the European settlement. These native tribes were relatively affluent because of the abundance of salmon runs, and engaged in lavish signalling, such as with their famous potlatches. Seeing as how there are Atlantic salmon runs in places like Norway and Scotland one can make even closer correspondences perhaps!

Stonehenge-GreenAs I have stated before just because we have no written records of this period, we can not assume that these were necessarily the fragmented and scattered “small-scale societies” which we’re familiar with today. There may have been ideologically motivated political coalitions and alliances which broke down along ethnic and cultural lines. In the paper above the authors argue that there is evidence that a climatic constraint, crops which do not have a good yield in cooler or warmer temperatures, is a weak hypothesis. If so I wonder if it is a bit too pat to simply model the dynamics as a diffusive “bottom up” process. Seems plausible enough for much of Europe where Mesolithic populations were thin on the ground because of local carrying capacity, but I suspect that the encounter between dense agglomerations of farmers and fishermen resulted in an inevitable ramp up of political integration and consolidation, as villages and tribes had to coordinate together because of a positive feedback loop of conflict.

Image Credit: Lordkinbote, Mactographer

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Ancient Egyptian farmer ploughing a field

Recently several weblogs have pointed to a new working paper on the role of plough-based agriculture vs. hoe-based agriculture in shaping cultural expectations about male and female labor force participation specifically, and the differentiation of gender roles more generally. My first reaction was: “doesn’t everyone know this already?” I am a cursory reader of the anthropological literature and the assumption that a shift from relatively extensive hoe-based agriculture (e.g., slash & burn, gardening, etc.) to a more intensive plough-based mode of production seems to suffuse the literature. Before touching on the major points in the paper itself I did a quick literature search, on the order of five minutes, and found something from 1928 which already assumed the major parameters which are now being mooted today, The Division of Work According to Sex in African Hoe Culture. I read the whole paper, and it remains surprisingly relevant (though some of the terminology and frameworks are a bit dated naturally). Here’s a selection:

Eduard Han, to whom the ethnological study of economics owes a considerable number of important discoveries which have been published repeatedly and in varying forms, seems to have paid scarcely enough attention to the good work of the scholars who preceded him in the fight for the recognition of the outstanding position of women in the lower forms of soil cultivation. Steinmetz and quite recently Koppers,’ have pointed out that Buckland already attributed to the female sex the invention of the most ancient method of soil cultivation, or hoe culture…Here we find, in particular,a clearer statement of the arguments of Grosse, Bachofen, and others about the connexion of matriarchal society and lower forms of soil cultivation. Matriarchy and hoe culture are assigned to definite chronologically determined stages of civilization (older forms of the so-called ‘two class culture’, and later ones of ‘bow culture’). Koppers, of the Austrian branch associates matriarchy and hoe culture with these two civilizations….

It is not our business here to study in detail the researcheson the zones of culture,which may be regardedas successfulup to a certain point, though we shall have to refer to them incidentally. It suffices to state that a connexion between woman and hoe culture, nay more, between that social system where the woman rules, matriarchal society, and primitive soil cultivation is universally acknowledged to exist.

Ignore some of the terms and concepts which might seem loaded or outmoded today. Rather, observe that in 1928 a distinction between hoe-based and plough-based agriculture was widely accepted in terms of the cultural consequences. Why? Just take a look at an old-fashioned plough vs. hoe (at least old-fashioned compared to the sort of mechanized devices you can find in catalogs today):

Manual plough & hoe, credit Jonathunder

Both the plough and the hoe serve the same general purpose, to prepare and maintain fields for the purpose of agriculture. The plough has more up-front fixed costs, because of its greater size and complexity, as well as a greater maintenance cost in terms of usage, because it requires more effort. But it is far more effectual than the hoe in its task of preparing and maintaining soil integrity for a host of crops. In particular, the two staffs of life in Eurasia which are associated with intensive agriculture: wheat and rice. Additionally, the physical demands of the plough, as well as its coupling with work animals, means that in general men have an advantage in generating productivity from the tool in relation to women. This is just a function of biology, as men tend to be larger and have more upper body strength. In societies where the plough reigns supreme the men dominate the public cultivated fields (I’ve been to rural Bangladesh, and the men perform most of the back-breaking labor in the paddies, while the women often engage in processing at home as well as handicrafts). In contrast it turns out be a truism that in societies where agriculture is “women’s work” the implement of choice tends to be the hoe, where they are not at great disadvantage to men in terms of marginal product (though even in these societies men may clear forests and do other extremely physically demanding tasks to prepare the ground for the women, who will follow in their wake).

civAs implied above, the plough tends to be associated with farming in more populous societies at the heart of the Old World Ecumene, while the hoe is generally found in more “small-scale” societies. Presumably all plough cultures went through though a hoe phase, just as intensive agriculture which is squeezed up against the Malthusian margin generally is preceded by a period of extensive agriculture where land is in surplus to labor. But a key point is that cultures do not emerge and evolve purely through endogenous social forces, but are constrained by exogenous parameters. Not only are some regions more suitable to particular modes of production (e.g., farming, animal husbandry, transhumance, etc.), but the details of production can vary a great deal. Even in a nation as ethnically homogenized by centuries of top-down fiat such as China the divide between the north and south of the country is a structural constant due to different climatic regimes and geological conditions.

So what does the new paper add? I am not familiar with the economic literature in this area, so I do not know if the methods are novel in terms of their application to this subject, but the authors use a formal statistical framework to confirm the correlation between mode of agriculture and gender roles. They do not smoke out novel or new correlations, rather, they place a specific number so as to render the broad-brush observation precise. In this way ironically the economists who bandy about fancy regression models actually make a mental picture of social phenomena more accessible to those without specific “thick” local knowledge.

The Origins of Gender Roles: Women and the Plough:

This paper studies the historic origins of current differences in norms and beliefs about the role of women in society. We show that, consistent with anthropological hypotheses, societies with a tradition of plough agriculture tend to have the belief that the natural place for women is inside the home and the natural place for men is outside the home. Looking across countries, subnational districts, ethnic groups and individuals, we identify a link between historic plough-use and a number of outcomes today, including female labor force participation, female participation in politics, female ownership of firms, the sex ratio and self-expressed attitudes about the role of women in society. Our identification exploits variation in the historic suitability of the environment of ancestors for growing crops that differentially benefited from the adoption of the plough. We examine culture as a mechanism by looking at first and second generation immigrants with different cultural backgrounds living within the US.

In the paper they cite a 1970 book, Womans Role in Economic Development, for the hypothesis they’re testing. I just want to emphasize again that all the pieces of the model were already widely circulating in anthropological circles implicity, as is made clear by the 1928 paper I mentioned above. It is important to remember that we come to the new paper with a strong expectation in the direction of the conclusions which they found.

Below are two maps which show the distributions of plough vs. hoe societies:

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The first map illustrates usage by ethnic group in their database. It is obvious that there are many more hoe farming populations than plough farmings. But, many more as individuals are from plough farming cultures. Why the difference? In the latter case the analogy can be made between the replacement of hunting & gathering and farming; plough farmers simply had greater per unit productivity and so could support much higher population levels than hoe farmers in regions where crops amenable to their intensive techniques could flourish. In their sample “86% of the ethnicities did not introduce the plough, in 12.18% of the societies, the plough was used, and in 1.5% of the plough was not initially used, but it was adopted after European contact.” In Brazil today the vast majority of ethnic groups were not plough farmers in 1500, but the majority of Brazilians are descended from plough farmers (even counting Africans as hoe farmers it seems likely that there is a preponderance of European ancestral contribution to Brazil in relation to African). Remember that even if you count the dozens of Portuguese speaking ethno-racial constructs among Brazilians as ethnic groups they’re still outnumbered by the small-scale societies of the Amazon!

Though the real yield of the paper is its general quantitative finding, which I will get to, it has to be framed in the broader area-specific patterns. For example, Northern India and Southern India traditionally exhibit very different gender relations patterns, as well as agricultural traditions. From the paper:

Boserup reports data for regional differences in women’s activities in different regions of India. She finds that in the South, where the plough was not present, there is a high fraction of women in the labor force compared to the North (36% versus 26%). This difference is present not only in agriculture (40% versus 29%), but also in other sectors such as construction (17% versus 6%), trade (17% versus 6%), transport and services (27% versus 13%) and other industries more generally (17% versus 6%). The author also notes that “in India the connection between the work of women and the direction of marriage payment is close and unmistakable. . . In region where women do most of the agricultural work it is the bridegroom who pay bride wealth, but where women are less actively engaged in agriculture, marriage payments come usually from the girl’s family” also “In some of the farming communities in Northern India, where women do little work in agriculture and the parents know that a daughter will in due course cost them the payment of a dowry, it was customary in earlier time to limit the number of surviving daughters by infanticide. This practice has disappeared but nevertheless the ratio of female to male population in these districts continues to be abnormal compared to other regions of India and to tribes with working women living in the same region”.

428px-Aishwarya_Rai_CannesIn the 20th century India has exhibited a relative trend toward cultural homogenization. But ethnology and anthropology were well developed enough early in the 20th century that practices which would decline or disappear were attested for many mainstream groups in south India. The Nairs and Bunts for example practiced (and some continue to pactice) matrilineal inheritance (Aishwarya Rai is a Bunt). Interestingly, there are groups in northeast India of Tibeto-Burma or Austro-Asiatic origin which practice both matrilineality and matrilocality. Not only is inheritance defined through the maternal line, but men move to the villages of their wives. This is in sharp contrast to the patriarchal bias evident in the Indo-Aryan speaking societies of North India. The “evil mother in law” who torments a young woman who marries into the family, who eventually becomes the “evil mother in law” in her own right after she gives birth to a son who will inherit, seems almost a cultural trope in these societies. Women are “strangers” who are coopted into the patrilineages through their sons, and ultimately become some of the most egregious enforcers of the norms which perpetuate the hyper-patriarchy of North India.

A quick inspection of the map above will show that it is the regions where hoe agriculture is also practiced which are less patriarchal. The highlands of Meghalaya, the the states of Nagaland, Manipur, Tripura and Mizoram, are really extensions of the broader Southeast Asian zone of slash & burn extensive agriculture, so the trend exists outside of Southeast Asia. The “hill people” in Burma, Thailand, Laos, and Thailand, occupy culturally marginalized positions, and probably are a snapshot of a dynamic which was common across much of the Old World.

In any case, speaking of maps, look at this one which compares sex ratio and literacy rates in India:


South India has higher literacy rates, and more normal sex ratios, indicative of relatively equitable gender relations. But, there are more developed regions of North India, like Punjab, which have massive sex ratio skews, while the tribal dominated regions of Central India combine low levels of development along with relatively equitable sex relations. What you tend to see is that cultures which are the most developed and least developed have the most equitable relations between the genders, while those in the middle are generally more conventionally male-dominated.

ploughtable1That’s where the statistical framework presented in the paper is so useful: one can control for confounding variables. Basically what they seem to have done is integrated modern geodata with older ethnographic information. Not only that, but they weighted the geographical variation by population density. So what the paper is popping out are spatial correlations of the variables of interest. To the left you see the output from an OLS regression. The dependent variable is the extent of female labor force participation as the dependent variable (as six categories). The first row shows the effect of the introduction of the plough, with the second two columns introducing controls. Remember that more plough societies have become developed than hoe societies, and developed societies tend to have more formal female labor force participation. The data set is broken down by ethnicity here. Note that the R-squared is capturing the proportion of the variance of Y explainable by X(s).

Obviously ethnic group level analysis is going to be somewhat problematic, because the data sets aren’t as well attested on this scale (e.g., labor force participation of Naga women as a percentage value?). On the other hand, they had better measures on the country and district and individual level, because the World Values Survey, and a host of statistical organizations, track numbers internationally which can be related together.

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The pre-print is freely available, so I’ll point you to that to make sense of the numbers in the above tables if they mystify you. Basically they’re supporting the general anthropological hunch that plough farming societies tend to be more patriarchal, all things equal. The final results section shows that immigrants to the United States impart to their descendants the same values. I do not find this surprising, though again it is useful to peg the exact magnitude of the correlations as they do. The majority of the world’s population are no longer primary producers, but most are recent descendants of primary producers. (around 50% of Americans lived on family farms just before 1900).

Ultimately this goes back to the foragers & farmers debate. I have argued for years that the “traditional” and “conservative” values which emerged after the rise of agriculture, and crystallized during the Axial Age, are actually cultural adaptations to existence in the Malthusian mass societies which arose as the farmers pushed up against the production frontier. As the world “filled up” there was a necessary switch from extensive to intensive agriculture, and social controls needed to be more powerful so as to keep the masses of humanity in some sort of meta-stable equilibrium. The rise of institutional religions, conscript armies, and national identities, all bubbled up as adaptations to a world where a few controlled the many, and the many persisted on the barest margin of subsistence.

But this is not to say that the world before the ploughman was a paradise. I believe it too was Malthusian. Humans are animals, and naturally hit a “carrying capacity.” But there’s Malthusian, and then there’s Malthusian. There were differences between the lives of hunter-gatherers on the margin, and farmers on the margin. Some scholars hypothesize that interpersonal violence was more common, not less, among hunter-gatherers, because there was no central authority regulating conflicts. More frequent unexpected deaths by hunter-gatherers may have constantly relieved pressures on small bands (as well as the fact that there was a check on births due to the problems of moving more than one infant at a time in a roving band). In contrast, it may be that famine and plague were the means by which nature re-calibrated the populations of farmers, who culled themselves off in the course of their lives through violence far less often. This is not because farmers necessarily were pacific angels, rather, the powerful men who rose with the mass societies valued individuals as sources of tax. Too much conflict which reduced population would naturally leave less aggregate rent, so there was a strong incentive for the thugs in charge keep their sheep alive and producing.

The above is a rather materialist economic reading of power relations. One could create a narrative of moral evolution over time, and the expansion of the arc of humanity with the spread of universal religions. I think the two variables are related, and in any case the description of what happened remains the same. But now we’re in a third age. We’re not trapped by Malthusian parameters, because gains in economic productivity haven’t been swamped by population growth. Rather, on the contrary a demographic transition has occurred across much of the world, producing mass affluence.

397px-Body_artWith mass affluence has come liberalism, post-materialism, and all sorts of ideas and movements predicated on self-actualization. The converse is that the traditional values and social controls necessary for the proper maintenance of human civilization during the millennia of the ploughman have come under attack, and those who defend them style themselves conservatives and reactionaries. Ironically the flowering of the individualist ethos has resulted in a reversion to the relative lack of mass conformity, which replicates the diversity across small-scale societies. I say mass conformity because individuals still conform within their own subcultures, it is just that the mass culture has shattered into many smaller constituent pieces (e.g., the rise of “urban tribes”).

We should not proliferate categories beyond what is needed. But the story of hoe vs. plough agriculturalists shows that a simple hunter-gatherer vs. farmer narrative does not suffice. In some ways the hoe agriculturalist remains more like the hunter-gatherer, and in some ways more like his or her fellow agriculturalist. The most polygynous societies for example are arguably those of hoe based agriculturalists, as well as nomads. In contrast, hunter-gatherers and ploughman tend to be more monogamous, at least in a genetic sense.

We need to evaluate human nature and society at its true joints. That may require more complexity than is pithy, but so be it.

Note: I used the British spelling “plough” because it looked right to me.

Image credits: Nomadtales, Georges Biard, kris krüg

Razib Khan
About Razib Khan

"I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. If you want to know more, see the links at"