GUNS, GERMS, AND STEEL (GGS) IS ABOUT WHY THE RISE OF complex human societies unfolded differently on different continents over the last 13,000 years. I finished revising the manuscript in 1996, and it was published in 1997. Since then, I have been involved mostly in work on other projects, especially on my next book about collapses of societies. Hence seven years’ distance in time and focus now separates me from GGS’s writing. How does the book look in retrospect, and what has happened to change or extend its conclusions since its publication? To my admittedly biased eye, the book’s central message has survived well, and the most interesting developments since its publication have involved four extensions of the story to the modern world and to recent history.
My main conclusion was that societies developed differently on different continents because of differences in continental environments, not in human biology. Advanced technology, centralized political organization, and other features of complex societies could emerge only in dense sedentary populations capable of accumulating food surpluses—populations that depended for their food on the rise of agriculture that began around 8,500 B.C. But the domesticable wild plant and animal species essential for that rise of agriculture were distributed very unevenly over the continents. The most valuable domesticable wild species were concentrated in only nine small areas of the globe, which thus became the earliest homelands of agriculture. The original inhabitants of those homelands thereby gained a head start toward developing guns, germs, and steel. The languages and genes of those homeland inhabitants, as well as their livestock, crops, technologies, and writing systems, became dominant in the ancient and modern world.
Discoveries in the last half-dozen years, by archaeologists, geneticists, linguists, and other specialists, have enriched our understanding of this story, without changing its main outlines. Let me mention three examples. One of the biggest gaps in GGS’s geographic coverage involved Japan, about whose prehistory I had little to say in 1996. Recent genetic evidence now suggests that the modern Japanese people are the product of an agricultural expansion similar to others discussed in GGS: an expansion of Korean farmers, beginning around 400 B.C., into southwestern Japan and then advancing northeast up the Japanese archipelago. The immigrants brought intensive rice agriculture and metal tools, and they mixed with the original Japanese population (related to the modern Ainu) to produce the modern Japanese, much as expanding Fertile Crescent farmers mixed with Europe’s original hunter/gatherer population to produce modern Europeans.
As another example, archaeologists originally assumed that Mexican corn, beans, and squashes reached the southeastern United States by the most direct route via northeastern Mexico and eastern Texas. But it is now becoming clear that this route was too dry for farming; those crops instead took a longer route, spreading from Mexico into the southwestern United States to trigger the rise of Anasazi societies there, and then spreading east from New Mexico and Colorado through river valleys of the Great Plains into the southeastern United States.
As a final example, in Chapter 10 I contrasted the frequency of repeated independent domestications and slow spreads of the same or related plants along the Americas’ north/south axis with the predominantly single domestications and rapid east/west spreads of Eurasian crops. Even more examples of those two contrasting patterns have continued to turn up, but it now appears that most or all of Eurasia’s Big Five domestic mammals also underwent repeated independent domestications in different parts of Eurasia—unlike Eurasia’s plants, but like the Americas’ plants.
These and other discoveries add details, which continue to fascinate me, to our understanding of how agriculture’s rise triggered the rise of agriculturally based complex societies in the ancient world. However, the biggest advances building on GGS have involved extensions into areas that were not the book’s main focus. Since publication, thousands of people have written, phoned, e-mailed, or buttonholed me to tell me of parallels or contrasts that they noticed between the ancient continental processes of GGS and the modern or recent processes that they study. I’ll tell you about four of these revelations: briefly, the illuminating example of New Zealand’s Musket Wars; the perennial question “Why Europe, not China?” in more detail, parallels between competition in the ancient world and in the modern business world; and GGS’s relevance to why some societies today are rich while others are poor.
IN 1996 I DEVOTED one brief paragraph (in Chapter 13) to a phenomenon in 19th-century New Zealand history termed the Musket Wars, as an illustration of how powerful new technologies spread. The Musket Wars were a complicated, poorly understood series of tribal wars among New Zealand’s indigenous Maori people, between 1818 and the 1830s—wars by which European guns spread among tribes that had previously fought one another with stone and wooden weapons. Two books published since then have increased our understanding of that chaotic period of New Zealand history, placed it in a broader historical context, and made its relevance to GGS even clearer.
In the early 1800s, European traders, missionaries, and whalers began to visit New Zealand, which had been occupied 600 years previously by Polynesian farmers and fishermen known as Maoris. The first European visitors were concentrated at New Zealand’s northern end. Those northern Maori tribes with the earliest access to Europeans thereby became the first tribes to acquire muskets, which gave them a big military advantage over all the other tribes lacking muskets. They used that advantage to settle scores with neighboring tribes that were their traditional enemies. But they also used muskets for a new type of warfare: long-distance raids against Maori tribes hundreds of miles away, carried out in order to outdo rivals in acquiring slaves and prestige.
At least as important as European muskets in making long-distance raids feasible were European-introduced potatoes (originating in South America), which yielded many more tons of food per acre or per farmer than did traditional Maori agriculture based on sweet potatoes. The main limitation that had previously prevented Maoris from undertaking long raids had been the twin problems of feeding warriors away from home for a long time, and feeding the at-home population of women and children dependent on the would-be warriors to stay home and grow sweet potatoes. Potatoes solved that bottleneck. Hence a less heroic term for the Musket Wars would be the Potato Wars.
Whatever they are called, the Musket/Potato Wars proved very destructive, killing about one-quarter of the original Maori population. The highest body counts arose when a tribe with lots of muskets and potatoes attacked a tribe with few or none. Of the tribes not among the first to acquire muskets and potatoes, some were virtually exterminated before they could acquire them, while others made determined efforts to acquire them and thereby restore the previous military equilibrium. One episode in these wars was the conquest and mass killing of Moriori tribes by Maori tribes, as described in Chapter 2.
The Musket/Potato Wars illustrate the main process running through the history of the last 10,000 years: human groups with guns, germs, and steel, or with earlier technological and military advantages, spreading at the expense of other groups, until either the latter groups became replaced or everyone came to share the new advantages. Recent history furnishes innumerable examples as Europeans expanded to other continents. In many places the non-European locals never got a chance to acquire guns and ended up losing their lives or their freedom. However, Japan did succeed in acquiring (actually, reacquiring) guns, preserved its independence, and within 50 years used its new guns to defeat a European power in the Russo-Japanese war of 1904–5. North American Plains Indians, South American Araucanian Indians, New Zealand’s Maoris, and Ethiopians acquired guns and used them to hold off European conquest for a long time, though they were ultimately defeated. Today, Third World countries are doing their best to catch up with the First World by acquiring the latter’s technological and agricultural advantages. Such spreads of technology and agriculture, arising ultimately from competition between human groups, must have happened at innumerable other times and places over the past 10,000 years.
In that sense, there was nothing unusual about New Zealand’s Musket/Potato Wars. While those wars were a purely local phenomenon confined to New Zealand, they are of worldwide interest because they furnish such a clear example, so narrowly confined in space and time,of so many other similar local phenomena. Within about two decades following their introduction to the northern end of New Zealand, muskets and potatoes had spread 900 miles to the southern end of New Zealand. In the past, agriculture, writing, and improved pre-gun weapons took much longer to spread much greater distances, but the underlying social processes of population replacement and competition were essentially the same. Now we are wondering whether nuclear weapons will proliferate around the world by the same often-violent process, from the eight countries that presently possess them.
A SECOND AREA of active discussion since 1997 falls under a heading that could be termed “Why Europe, not China?” Most of GGS concerned differences between continents: i.e., the question of why some Eurasians rather than Aboriginal Australians, sub-Saharan Africans, or Native Americans were the ones to expand over the world within the past millennium. However, I realized that many readers would also wonder “Why, among Eurasians, was it Europeans rather than Chinese or some other group that expanded?” I knew that my readers would not let me get away with concluding GGS without saying anything about this obvious question.
Hence I briefly considered it in the book’s epilogue. I suggested that the underlying reason behind Europe’s overtaking China was something deeper than the proximate factors suggested by most historians (e.g., China’s Confucianism vs. Europe’s Judeo-Christian tradition, the rise of western science, the rise of European mercantilism and capitalism, Britain’s deforestation coupled with its coal deposits, etc.). Behind these and other proximate factors, I saw an “Optimal Fragmentation Principle”: ultimate geographic factors that led to China becoming unified early and mostly remaining unified thereafter, while Europe remained constantly fragmented. Europe’s fragmentation did, and China’s unity didn’t, foster the advance of technology, science, and capitalism by fostering competition between states and providing innovators with alternative sources of support and havens from persecution.
Historians have subsequently pointed out to me that Europe’s fragmentation, China’s unity, and Europe’s and China’s relative strengths were all more complex than depicted in my account. The geographic boundaries of the political/social spheres that could usefully be grouped as “Europe” or “China” fluctuated over the centuries. China led Europe in technology at least until the 15th century and might do so again in the future, in which case the question “Why Europe, not China?” might only refer to an ephemeral phenomenon without deep explanation. Political fragmentation has more complex effects than only providing a constructive forum for competition: for instance, competition can be destructive as well as constructive (think of World Wars I and II). Fragmentation itself is a multifaceted rather than a monolithic concept: its effect on innovation depends on factors such as the freedom with which ideas and people can move across the boundaries between fragments, and whether the fragments are distinct or just clones of each other. Whether fragmentation is “optimal” may also vary with the measure of optimality used; a degree of political fragmentation that is optimal for technological innovation may not be optimal for economic productivity, political stability, or human happiness.
My sense is that a large majority of social scientists still favors proximate explanations for the different courses of European and Chinese history. For example, in a thoughtful recent essay Jack Goldstone stressed the importance of Europe’s (especially Britain’s) “engine science,” meaning the applications of science to the development of machines and engines. Goldstone wrote, “Two problems faced all pre-industrial economies in regard to energy: amount and concentration. The amount of mechanical energy available to any pre-industrial economy was limited to water flows, animals or people who could be fed, and wind that could be captured. In any geographically fixed area, this amount was strictly limited.…It is difficult to overstate the advantage given to the first economy or military/political power to devise a means to extract useful work from the energy in fossil fuels…. [It was] the application of steam power to spinning, to water and surface transport, to brick-making, grain-threshing, iron-making, shoveling, construction, and all sorts of manufacturing processes that transformed Britain’s economy…. It thus may be that, far from a necessary development of European civilization, the rich development of engine science was the chance outcome of specific, even if highly contingent, circumstances that happened to arise in 17th- and 18th-century Britain.” If this reasoning is correct, then a search for deep geographic or ecological explanations will not be profitable.
The opposite minority view, similar to my view expressed in the epilogue of GGS, has been argued in detail by Graeme Lang: “Differences between Europe and China in ecology and geography helped to explain the very different fates of science in the two regions. First, [rainfall] agriculture in Europe provided no role for the state, which remained far from local communities most of the time, and when the agricultural revolution in Europe produced a growing agricultural surplus, this allowed the growth of relatively autonomous towns along with urban institutions such as universities prior to the rise of the centralized states in the late Middle Ages. [Irrigation and water-control] agriculture in China, by contrast, favored the early development of intrusive and coercive states in the major river valleys, while towns and their institutions never achieved the degree of local autonomy found in Europe. Second, the geography of China, unlike that of Europe, did not favor the prolonged survival of independent states. Instead, China’s geography facilitated eventual conquest and unification over a vast area, followed by long periods of relative stability under imperial rule. The resulting state system suppressed most of the conditions required for the emergence of modern science…. The explanation outlined above is certainly oversimplified. However, one of the advantages of this kind of account is that it escapes the circularity which often creeps into explanations which do not go deeper than social or cultural differences between Europe and China. Such explanations can always be challenged with a further question: why were Europe and China different with regard to those social or cultural factors? Explanations rooted ultimately in geography and ecology, however, have reached bedrock.”
It remains a challenge for historians to reconcile these different approaches to answering the question “Why Europe, not China.” The answer may have important consequences for how best to govern China and Europe today. For example, from Lang’s and my perspective, the disaster of China’s Cultural Revolution of the 1960s and 1970s, when a few misguided leaders were able to close the school systems of the world’s largest country for five years, may not be a unique one-time-only aberration, but may presage more such disasters in the future unless China can introduce far more decentralization into its political system. Conversely, Europe, in its rush toward political and economic unity today, will have to devote much thought to how to avoid dismantling the underlying reason behind its successes of the last five centuries.
THE THIRD RECENT extension of GGS’s message to the modern world was to me the most unexpected one. Soon after the book’s publication, it was reviewed favorably by Bill Gates, and then I began receiving letters from other business people and economists who pointed out possible parallels between the histories of entire human societies discussed in GGS and the histories of groups in the business world. This correspondence concerned the following broad question: what is the best way to organize human groups, organizations, and businesses so as to maximize productivity, creativity, innovation, and wealth? Should your group have a centralized direction (in the extreme, a dictator), or should there be diffuse leadership or even anarchy? Should your collection of people be organized into a single group, or broken down into a small or large number of groups? Should you maintain open communication between your groups, or erect walls of secrecy between them? Should you erect protectionist tariff walls against the outside, or should you expose your business to free competition?
These questions arise at many different levels and for many types of groups. They apply to the organization of entire countries: remember the perennial arguments about whether the best form of government is a benign dictatorship, a federal system, or an anarchical free-for-all. The same questions arise about the organization of different companies within the same industry. How can we account for the fact that Microsoft has been so successful recently, while IBM, which was formerly successful, fell behind but then drastically changed its organization and improved its success? How can we explain the different successes of different industrial belts? When I was a boy growing up in Boston, Route 128, the industrial belt around Boston, led the world in scientific creativity and imagination. But Route 128 has fallen behind, and now Silicon Valley is the center of innovation. The relations of businesses to one another in Silicon Valley and on Route 128 are very different, possibly resulting in those different outcomes.
Of course, there are also the famous differences between the productivities of the economies of whole countries, such as Japan, the United States, France, and Germany. Actually, though, there are big differences between the productivity and wealth of different business sectors even within the same country. For example, the Korean steel industry is equal in efficiency to ours, but all other Korean industries lag behind their American counterparts. What is it about the different organization of these various Korean industries that accounts for their differences in productivity within the same country?
Obviously, answers to these questions about differences in organizational success depend partly on the idiosyncrasies of individuals. For example, the success of Microsoft has surely had something to do with the personal talents of Bill Gates. Even with a superior corporate organization, Microsoft would not be successful with an ineffectual leader. Nevertheless, one can still ask: all other things being equal, or else in the long run, or else on the average, what form of organization of human groups is best?
My comparison of the histories of China, the Indian subcontinent, and Europe in the epilogue of GGS suggested an answer to this question as applied to technological innovation in whole countries. As explained in the preceding section, I inferred that competition between different political entities spurred innovation in geographically fragmented Europe, and that the lack of such competition held innovation back in unified China. Would that mean that a higher degree of political fragmentation than Europe’s would be even better? Probably not: India was geographically even more fragmented than Europe, but less innovative technologically. This suggested to me the Optimal Fragmentation Principle: innovation proceeds most rapidly in a society with some optimal intermediate degree of fragmentation: a too-unified society is at a disadvantage, and so is a too-fragmented society.
This inference rang a bell with Bill Lewis and other executives of McKinsey Global Institute, a leading consulting firm based in Washington, D.C., which carries out comparative studies of the economies of countries and industries all over the world. The executives were so struck by the parallels between their business experience and my historical inferences that they presented a copy of GGS to each of the firm’s several hundred partners, and they presented me with copies of their reports on the economies of the United States, France, Germany, Korea, Japan, Brazil, and other countries. They, too, detected a key role of competition and group size in spurring innovation. Here are some of the conclusions that I gleaned from conversations with McKinsey executives and from their reports:
We Americans often fantasize that German and Japanese industries are super-efficient, exceeding American industries in productivity. In reality, that’s not true: on the average across all industries, America’s industrial productivity is higher than that in either Japan or Germany. But those average figures conceal big differences among the industries of each country, related to differences in organization—and those differences are very instructive. Let me give you two examples from McKinsey case studies on the German beer industry and the Japanese food-processing industry.
Germans make wonderful beer. Every time that my wife and I fly to Germany for a visit, we carry with us an empty suitcase, so we can fill it with bottles of German beer to bring back to the United States and enjoy over the following year. Yet the productivity of the German beer industry is only 43 percent that of the U.S. beer industry. Meanwhile, the German metalworking and steel industries are equal in productivity to their American counterparts. Since the Germans are evidently perfectly capable of organizing industries well, why can’t they do so when it comes to beer?
It turns out that the German beer industry suffers from small-scale production. There are a thousand tiny beer companies in Germany, shielded from competition with one another because each German brewery has virtually a local monopoly, and they are also shielded from competition with imports. The United States has 67 major beer breweries, producing 23 billion liters of beer per year. All of Germany’s 1,000 breweries combined produce only half as much. Thus the average U.S. brewery produces 31 times more beer than the average German brewery.
This fact results from local tastes and German government policies. German beer drinkers are fiercely loyal to their local brand, so there are no national brands in Germany analogous to our Budweiser, Miller, or Coors. Instead, most German beer is consumed within 30 miles of the factory where it is brewed. Therefore, the German beer industry cannot profit from economies of scale. In the beer business, as in other businesses, production costs decrease greatly with scale. The bigger the refrigerating unit for making beer, and the longer the assembly line for filling bottles with beer, the lower the cost of manufacturing beer. Those tiny German beer companies are relatively inefficient. There’s no competition; there are just a thousand local monopolies.
The local beer loyalties of individual German drinkers are reinforced by German laws that make it hard for foreign beers to compete in the German market. The German government has so-called beer purity laws that specify exactly what can go into beer. Not surprisingly, those government purity specifications are based on what German breweries put into beer, and not on what American, French, and Swedish breweries like to put into beer. Because of those laws, not much foreign beer gets exported to Germany, and because of inefficiency and high prices much less of that wonderful German beer than you would otherwise expect gets sold abroad. (Before you object that German Löwenbräu beer is widely available in the United States, please read the label on the next bottle of Löwenbräu that you drink here: it’s not produced in Germany but in North America, under license, in big factories with North American productivity and efficiencies of scale.)
The German soap industry and consumer electronics industry are similarly inefficient; their companies are not exposed to competition with one another, nor are they exposed to foreign competition, and so they do not acquire the best practices of international industry. (When is the last time that you bought an imported TV set made in Germany?) But those disadvantages are not shared by the German metal and steel industries, in which big German companies have to compete with one another and internationally, and thus are forced to acquire the best international practices.
My other favorite example from the McKinsey reports concerns the Japanese food-processing industry. We Americans tend to be paranoid about Japanese efficiency, and it is indeed formidable in some industries—but not in food-processing. The efficiency of the Japanese food-processing industry is a miserable 32 percent that of ours. There are 67,000 food-processing companies in Japan, compared to only 21,000 in the United States, which has twice Japan’s population—so the average U.S. food-processing company is six times bigger than its Japanese counterpart. Why does the Japanese food-processing industry, like the German beer industry, consist of small companies with local monopolies? Basically, the answer is the same two reasons: local taste and government policies.
The Japanese are fanatics for fresh food. A container of milk in a U.S. supermarket bears only one date: the expiration date. When my wife and I visited a Tokyo supermarket with one of my wife’s Japanese cousins, we were surprised to discover that in Japan a milk container bears three dates: the date the milk was manufactured, the date it arrived at the supermarket, and the expiration date. Milk production in Japan always starts at one minute past midnight, so that the milk that goes to market in the morning can be labeled as today’s milk. If the milk were produced at 11:59 P.M., the date on the container would have to indicate that the milk was made yesterday, and no Japanese consumer would buy it.
As a result, Japanese food-processing companies enjoy local monopolies. A milk producer in northern Japan cannot hope to compete in southern Japan, because transporting milk there would take an extra day or two, a fatal disadvantage in the eyes of consumers. These local monopolies are reinforced by the Japanese government, which obstructs the import of foreign processed food by imposing a 10-day quarantine, among other restrictions. (Imagine how Japanese consumers who shun food labeled as only one day old feel about food 10 days old.) Hence Japanese food-producing companies are not exposed to either domestic or foreign competition, and they don’t learn the best international methods for producing food. Partly as a result, food prices in Japan are very high: the best beef costs $200 a pound, while chicken costs $25 a pound.
Some other Japanese industries are organized very differently from the food processors. For instance, Japanese steel, metal, car, car parts, camera, and consumer electronic companies compete fiercely and have higher productivities than their U.S. counterparts. But the Japanese soap, beer, and computer industries, like the Japanese food-processing industry, are not exposed to competition, do not apply the best practices, and thus have lower productivities than the corresponding industries in the United States. (If you look around your house, you are likely to find that your TV set and camera, and possibly also your car, are Japanese, but that your computer and soap are not.)
Finally, let’s apply these lessons to comparing different industrial belts or businesses within the United States. Since the publication of GGS, I’ve spent much time talking with people from Silicon Valley and from Route 128, and they tell me that these two industrial belts are quite different in terms of corporate ethos. Silicon Valley consists of lots of companies that are fiercely competitive with one another. Nevertheless, there is much collaboration—a free flow of ideas, people, and information among companies. In contrast, I’m told, the businesses of Route 128 are much more secretive and insulated from one another, like Japanese milk-producing companies.
What about the contrast between Microsoft and IBM? Since GGS was published, I’ve acquired friends at Microsoft and have learned about that corporation’s distinctive organization. Microsoft has lots of units, each comprised of 5 to 10 people, with free communication among units, and the units are not micromanaged; they are allowed a great deal of freedom in pursuing their own ideas. That unusual organization at Microsoft—which in essence is broken into many competing semi-independent units—contrasts with the organization at IBM, which until some years ago consisted of much more insulated groups and resulted in IBM’s loss of competitive ability. Then IBM acquired a new chief executive officer who changed things drastically: IBM now has a more Microsoft-like organization, and I’m told that IBM’s innovativeness has improved as a result.
All of this suggests that we may be able to extract a general principle about group organization. If your goal is innovation and competitive ability, you don’t want either excessive unity or excessive fragmentation. Instead, you want your country, industry, industrial belt, or company to be broken up into groups that compete with one another while maintaining relatively free communication—like the U.S. federal government system, with its built-in competition between our 50 states.
THE REMAINING EXTENSION of GGS has been into one of the central questions of world economics: why are some countries (like the United States and Switzerland) rich, while other countries (like Paraguay and Mali) are poor? Per-capita gross national products (GNP) of the world’s richest countries are more than 100 times those of the poorest countries. This is not just a challenging theoretical question giving employment to economics professors, but also one with important policy implications. If we could identify the answers, then poor countries could concentrate on changing the things that keep them poor and on adopting the things that make other countries rich.
Obviously, part of the answer depends on differences in human institutions. The clearest evidence for this view comes from pairs of countries that divide essentially the same environment but have very different institutions and, associated with those institutions, different per-capita GNPs. Four flagrant examples are the comparison of South Korea with North Korea, the former West Germany with the former East Germany, the Dominican Republic with Haiti, and Israel with its Arab neighbors. Among the many “good institutions” often invoked to explain the greater wealth of the first-named country of each of these pairs are effective rule of law, enforcement of contracts, protection of private property rights, lack of corruption, low frequency of assassinations, openness to trade and to flow of capital, incentives for investment, and so on.
Undoubtedly, good institutions are indeed part of the answer to the different wealths of nations. Many, perhaps most, economists go further and believe that good institutions are overwhelmingly the most important explanation. Many governments, agencies, and foundations base their policies, foreign aid, and loans on this explanation, by making the development of good institutions in poor countries their top priority.
But there is increasing recognition that this good-institutions view is incomplete—not wrong, just incomplete—and that other important factors need addressing if poor countries are to become rich. This recognition has its own policy implications. One cannot just introduce good institutions to poor countries like Paraguay and Mali and expect those countries to adopt the institutions and achieve the per-capita GNPs of the United States and Switzerland. The criticisms of the good-institutions view are of two main types. One type recognizes the importance of other proximate variables besides good institutions, such as public health, soil- and climate-imposed limits on agricultural productivity, and environmental fragility. The other type concerns the origin of good institutions.
According to the latter criticism, it is not enough to consider good institutions as a proximate influence whose origins are of no further practical interest. Good institutions are not a random variable that could have popped up anywhere around the globe, in Denmark or in Somalia, with equal probability. Instead, it seems to me that, in the past, good institutions always arose because of a long chain of historical connections from ultimate causes rooted in geography to the proximate dependent variables of the institutions. We must understand that chain if we hope, now, to produce good institutions quickly in countries lacking them.
At the time that I wrote GGS, I commented, “The nations rising to new power [today] are still ones that were incorporated thousands of years ago into the old centers of dominance based on food production, or that have been repopulated by peoples from those centers…. The hand of history’s course at 8,000 B.C. lies heavily on us.” Two new papers by economists (Olsson and Hibbs, and Bockstette, Chanda, and Putterman) have subjected this postulated heavy hand of history to detailed tests. It turns out that countries in regions with long histories of state societies or agriculture have higher per-capita GNP than countries with short histories, even after other variables have been controlled. The effect explains a large fraction of the variance in GNP. Even just among countries with still-low or recently low GNPs, countries in regions with long histories of state societies or agriculture, like South Korea, Japan, and China, have higher growth rates than countries with short histories, such as New Guinea and the Philippines, even though some of the countries with short histories are much richer in natural resources.
There are many obvious reasons for these effects of history, such as that long experience of state societies and agriculture implies experienced administrators, experience with market economies, and so on. Statistically, part of that ultimate effect of history proves to be mediated by the familiar proximate causes of good institutions. But there is still a large effect of history remaining after one controls for the usual measures of good institutions. Hence there must be other mediating proximate mechanisms as well. Thus a key problem will be to understand the detailed chain of causation from a long history of state societies and agriculture to modern economic growth, in order to help developing countries advance up that chain more quickly.
In short, the themes of GGS seem to me to be not only a driving force in the ancient world but also a ripe area for study in the modern world.