The Industrial and Neolithic Revolutions are surely the two fundamental transitions in the economic history of mankind. The Neolithic involved permanent settlement of previously nomadic, or at best partially foraging, small bands. At least seven independent times, bands somewhere in the world adopted settled agriculture. The new settlements tended to see an increase in inequality, the beginning of privately held property, a number of new customs and social structures, and, most importantly, an absolute decrease in welfare as measured in terms of average height and an absolute increase in the length and toil of working life. Of course, in the long run, settlement led to cities which led to the great inventions that eventually pushed mankind past the Malthusian bounds into our wealthy present, but surely no nomad of ten thousand years ago could have projected that outcome.
Now this must sound strange to any economist, as we can’t help but think in terms of rational choice. Why would any band choose to settle when, as far as we can tell, settling made them worse off? There are only three types of answers compatible with rational choice: either the environment changed such that the nomads who adopted settlement would have been even worse off had they remained nomadic, settlement was a Pareto-dominated equilibrium, or our assumption that the nomads were maximizing something correlated with height is wrong. All might be possible: early 20th century scholars ascribed the initial move to settlement to humans being forced onto oases in the drying post-Ice Age Middle East, evolutionary game theorists are well aware that fitness competitions can generate inefficient Prisoner’s Dilemmas, and humans surely care about reproductive success more than they care about food intake per se.
So how can we separate these potential explanations, or provide greater clarity as to the underlying Neolithic transition mechanism? Two relatively new papers, Andrea Matranga’s “Climate-Driven Technical Change“, and Kim Sterelny’s Optimizing Engines: Rational Choice in the Neolithic”, discuss intriguing theories about what may have happened in the Neolithic.
Matranga writes a simple Malthusian model. The benefit of being nomadic is that you can move to places with better food supply. The benefit of being sedentary is that you use storage technology to insure yourself against lean times, even if that insurance comes at the cost of lower food intake overall. Nomadism, then, is better than settling when there are lots of nearby areas with uncorrelated food availability shocks (since otherwise why bother to move?) or when the potential shocks you might face across the whole area you travel are not that severe (in which case why bother to store food?). If fertility depends on constant access to food, then for Malthusian reasons the settled populations who store food will grow until everyone is just at subsistence, whereas the nomadic populations will eat a surplus during times when food is abundant.
It turns out that global “seasonality” – or the difference across the year in terms of temperature and rainfall – was extraordinarily high right around the time agriculture first popped up in the Fertile Crescent. Matranga uses some standard climatic datasets to show that six of the seven independent inventions of agriculture appear to have happened soon after increases in seasonality in their respective regions. This is driven by an increase in seasonality and not just an increase in rainfall or heat: agriculture appears in the cold Andes and in the hot Mideast and in the moderate Chinese heartland. Further, adoption of settlement once your neighbors are farming is most common when you live on relatively flat ground, with little opportunity to change elevation to pursue food sources as seasonality increases. Biological evidence (using something called “Harris lines” on your bones) appears to support to idea that nomads were both better fed yet more subject to seasonal shocks than settled peoples.
What’s nice is that Matranga’s hypothesis is consistent with agriculture appearing many times independently. Any thesis that relies on unique features of the immediate post-Ice Age – such as the decline in megafauna like the Woolly Mammoth due to increasing population, or the oasis theory – will have a tough time explaining the adoption of agriculture in regions like the Andes or China thousands of years after it appeared in the Fertile Crescent. Alain Testart and colleagues in the anthropology literature have made similar claims about the intersection of storage technology and seasonality being important for the gradual shift from nomadism to partial foraging to agriculture, but the Malthusian model and the empirical identification in Matranga will be much more comfortable for an economist reader.
Sterelny, writing in the journal Philosophy of Science, argues that rational choice is a useful framework to explain not only why backbreaking, calorie-reducing agriculture was adopted, but also why settled societies appeared willing to tolerate inequality which was much less common in nomadic bands, and why settled societies exerted so much effort building monuments like Gobekli Tepe, holding feasts, and participating in other seemingly wasteful activity.
Why might inequality have arisen? Settlements need to be defended from thieves, as they contain stored food. Hence settlement sizes may be larger than the size of nomadic bands. Standard repeated games with imperfect monitoring tell us that when repeated interactions become less common, cooperation norms become hard to sustain. Hence collective action can only be sustained through mechanisms other than dyadic future punishment; this is especially true if farmers have more private information about effort and productivity than a band of nomadic hunters. The rise of enforceable property rights, as Bowles and his coauthors have argued, is just such a mechanism.
What of wasteful monuments like Gobekli Tepe? Game theoretic deliberate choice provides two explanations for such seeming wastefulness. First, just as animals consume energy in ostentatious displays in order to signal their fitness (as the starving animal has no energy to generate such a display), societies may construct totems and temples in order to signal to potential thieves that they are strong and not worth trifling with. In the case of Gobekli Tepe, this doesn’t appear to be the case, as there isn’t much archaeological evidence of particular violence around the monument. A second game theoretic rationale, then, is commitment by members of a society. As Sterelny puts it, the reason a gang makes a member get a face tattoo is that, even if the member leaves the gang, the tattoo still puts that member at risk of being killed by the gang’s enemies. Hence the tattoo commits the member not to defect. Settlements around Gobekli Tepe may have contributed to its building in order to commit their members to a set of norms that the monument embodied, and hence permit trade and knowledge transfer within this in-group. I would much prefer to see a model of this hypothesis, but the general point doesn’t seem impossible. At least, Sterelny and Matranga together provide a reasonably complete possible explanation, based on rational behavior and nothing more, of the seemingly-strange transition away from nomadism that made our modern life possible.
Kim Sterelny, Optimizing Engines: Rational Choice in the Neolithic?, 2013 working paper. Final version published in the July 2015 issue of Philosophy of Science. Andrea Matranga, “Climate-driven Technical Change: Seasonality and the Invention of Agriculture”, February 2015 working paper, as yet unpublished. No RePEc IDEAS page is available for either paper.
I guess I find the casual disregard for the anthropological literature a little disheartening.
No doubt. I am not an anthropologist, hence the title “The economics of the…” Both the papers discussed, especially the phil of science article, draw very heavily on the anthropological literature. The point is that game theoretic and Malthusian reasoning can suggest explanations for outcomes puzzling to the pure anthropologist; no one thinks economists or other social scientists can do the pure anthro work themselves.
Cool post, thanks for the heads up. I will be sure to check out these papers. The only other paper on the neolithic revolution I have seen is Guzman Weisdorf: http://www.sciencedirect.com/science/article/pii/S030438781000091X
Economic history is still so underrated.
I would suggest that you consider the possibility that the dense populations associated with agriculture had military advantages that allowed agriculture to spread by conquest rather than cultural diffusion. The genetic evidence seems to generally support this view.
There are some articles in ‘Labor in the ancient world’ http://www.amazon.com/Labor-Ancient-World-Piotr-Steinkeller/dp/3981484231
What about the alternative hypothesis that in those areas most conducive to agriculture, groups who discovered it could support a much higher population density than nomads, and were thus better equipped, by sheer numbers, to defend and gradually expand their territory.
Much ado is made of the shorter average heights and presumably lower level of nutrition per capita of farming peoples. What should be noted in the
next sentence is that many more people will *exist* per square kilometer in those communities. So, average nutritional intake in a given territory increases, even nutritional intake at the margin is just above subsistence. This doesn’t totally contradict the author’s argument as to the benefit of farming. If agricultural produced a more stable food source, more people could survive year after year at just above the subsistence level without dying in random bad year.
Another relevant reference is Boix’s 2015 book “Political Order and Inequality”, in which he emphasizes the role of technological change. Similarly to Matranga, he uses biological evidence (data on height).
Greg Dow and Clyde Reed have also been writing on this for a while, you might be interested in their research in this area. Their most recent published paper on this can be found at: http://www.sfu.ca/~gdow/download/jpe%202013.pdf
“Why would any band choose to settle when, as far as we can tell, settling made them worse off?”
You are allowing the fog of history to confuse immediate and longer term results. The answer is simple. At the time the choice toward more agriculture is made it was an excellent choice. It led to more food for the decision maker, and more kids, more of whom reached maturity. Once you state it this way the answer to the supposed dilemma is obvious. More kids had more kids, and after a few generations, the Malthusian trap was sprung. Now they had smaller family plots, worse living standards and diets, and all the problems of overcrowding, and a lack of mobility to boot.
Asking why foragers switched to farming is like asking why healthy adults choose to be crack addicts. Truth is, they don’t.
The Australian aborigines did not choose to go for agriculture- but the results for them were disastrous when they were invaded. However their elders have commented that infectious disease was uncommon prior to the European invasion.
Non agricultural societies have to remain at low population levels, and tribes normally guard their land very jealously.
Agriculture permits a higher population density- and the sacrifices associated with it are not immediate obvious. However that larger population can support territorial expansionism (at the point of a sword) and the production of grain allows for the accumulation of personal wealth.
So, as well as having other undesirable effects (a less balanced diet, close proximity increasing the spread of disease, tooth decay caused by eating carbohydrates which stick to teeth, and also by erosion of teeth from stone ground flour), the agricultural innovation allowed for amassing of personal wealth and personal armies. Finally it has led us close to the point of environmental collapse.
Agriculture seemed like a good idea at the time 😦
Yeah, subsequent to the initial conversion, the higher populations of agriculture spreads as we saw in Australia. But the question is why the initial bands settled to start the process, and the answer is that a long term bad idea (smoking crack was the example I used) can emerge out of shorter range rational decisions. Agriculture led to orders of magnitude more people with worse health, harder lives and less freedom. But the Malthusian Curse comes with a delay.
I will clarify that this all changed with the modern breakthrough and industrial revolution which emerged some time after 1776 (the Wealth of Nations). Since then we have seen an order of magnitude more population above agricultural societies along with phenomenally more prosperity, freedom, health and general well being.