Population, Technology and Fragmentation: The European Miracle Revisited
Journal of Development Economics , 108(C), 2014, pp.87-105.
Abstract: The effects of political fragmentation on long-run development seem to have changed over the course of human history. Technological leaders used to be empires, but the Industrial Revolution started in the fragmented Europe. This paper sets up a model to help us think about this puzzle. There are two sets of mechanisms at play: a standard scale effect, which benefits unified regions, since technology is a non-rivalrous good; and several competition effects, both negative (like wasteful armies) and positive (incentives to invest in new technologies). We apply the model to analyze the preindustrial divergence between China and Europe.
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A Dynamic Theory of Competence, Loyalty and Stability in Dictatorships
The B.E. Journal of Macroeconomics (Topics) , 12(1), 2012, pp.1-39
Abstract: This paper presents a dynamic model of power competition in a nondemocracy. In each period, a ruler from an incumbent dynasty is challenged. If he survives, he hands over power to a (biological or ideological) offspring. He can control his offspring's chances of surviving future threats, by choosing how competent and loyal administrators to hire, and how many. The society can stay for a long time on a volatile path where subsequent dynasties of rulers regularly replace one another, each purging the preceding dynasty's competent administrators, replacing them with loyalists, thus keeping competence bouncing around a low level. This may be followed by an endogenous transition to a path without such purges and a simultaneous rise in competence.
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Pacifying Monogamy
Journal of Economic Growth , 15(3), 2010, pp.235-262
Abstract: This paper proposes a theory of institutionally imposed monogamy. In a society where many women are allocated to the elite, there are high returns for the non-elite men to rebel. Monogamy, or "constrained" polygyny, can pacify non-elite men, and thus serve the elite's reproductive interests. The more unequal is the society, the stricter constraints the elite want to impose on themselves. This suggests how monogamy might have arisen in response to rising class cleavages, e.g., in the wake of the introduction of agriculture. Another result is that, if the elite can write a law that commits not only themselves but also any group that would come to replace them in a rebellion, then polygyny will be more constrained than if they cannot. We speculate that the Church in Europe may have facilitated the imposition of such binding constraints.
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From Malthusian War to Solovian Peace
Review of Economic Dynamics , 13(3), 2010, pp.616-636
Abstract: We present a two-country version of Hansen and Prescott's two-sector long-run growth model, introducing war by letting the countries take land from each other, at the cost of destroying capital and killing people. Because land is an input only in the Malthus sector the transition to a Solow economy brings a decline in warfare, broadly consistent with an observed 19th-century decrease in Great Power wars. We also find, inter alia, that if governments are Malthus-biased (care less about Solow output), the transition can lead temporarily to more war.
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Slavery and other property rights
Review of Economic Studies , 76(1), 2009, pp.319-342
Abstract: The institution of slavery is found mostly at intermediate stages of agricultural development and less often among hunter-gatherers and advanced agrarian societies. We explain this pattern in a growth model with land and labour as inputs in production and an endogenously determined property rights institution. The economy endogenously transits from an egalitarian state with equal property rights to a despotic slave society where the elite own both people and land; thereafter, it endogenously transits into a free labour society, where the elite own the land but people are free.
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Long-run trends in human body mass
Macroeconomic Dynamics , 11(3), 2007, pp.367-387
Abstract: Over the past two million years human body mass first increased and later declined, peaking about 50,000 years ago. This paper sets up a model of natural selection among body types to explain this pattern. Population, technology, and average body mass evolve endogenously and interdependently in such a way that a takeoff in technological progress generates rising population density and resource depletion. This in turn makes large bodies less useful in food procurement, while keeping their metabolism requirements high. The result is a shift in reproductive advantage from big to small bodies and an endogenous reversal of the time trend in body mass.
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Individual versus parental consent in marriage: implications for intra-household resource allocation and growth
(with Lena Edlund)
American Economic Review Papers & Proceedings , 96(2), 2006, pp.304-307
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The Galor-Weil model revisited: a quantitative exercise
Review of Economic Dynamics , 9(1), 2006, pp.116-142
Abstract: The long-run growth model of Galor and Weil (AER 2000) is examined quantitatively. We first give parametric forms to some functions which were only given on general form in the original article. We then choose numerical parameter values in line with calibrations of related long-run growth models, and with data. Finally, we simulate the model. We find, inter alia, that the time paths for population, and other variables, display oscillatory behavior: they move in endogenous cycles. As the economy transits from Malthusian stagnation to modern growth these oscillations die out. This is consistent with population growth rates fluctuating considerably in historical data, but having stabilized in modern economies. We also show that these cycles are not an artifact of the two-period life setting: allowing adults to live on after the second period of life with some probability does not make the oscillations go away. Rather, the cycles are driven by fertility being proportional to per-capita income minus the parental subsistence requirement. When population is large, and per-capita incomes close to subsistence, fertility is therefore sensitive to changes in population levels.
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Gender equality and long-run growth
Journal of Economic Growth , 8(4), 2003, pp.403-426
Abstract: This research suggests that long-run economic and demographic development in Europe can be better understood when related to long-term trends in gender equality, dating back to the spread of Christianity. We set up a growth model where gaps in female-to-male human capital arise at equilibrium through a coordination process. An economy which over a long stretch of time re-coordinates on continuously more equal equilibria--as one could argue happened in Europe--exhibits growth patterns qualitatively similar to that of Europe.
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From Malthus to modern growth: can epidemics explain the three regimes?
International Economic Review , 44(2), 2003, pp.755-777
Abstract: We model demographic and economic long-run development in a setting where mortality is endogenous and subject to epidemic shocks. The model replicates the full transition from Malthusian stagnation to modern growth. Consistent with the historical facts, the economy also passes an intermediate post-Malthusian phase where growth rates of both population and per capita income increase simultaneously, as mortality rates fall and become less volatile. The escape from the Malthusian trap is the result of a series of mild epidemic shocks, making it inevitable at some stage, but its timing random. Calibrations show that it can differ by thousands of generations, absent differences in exogenous parameters.
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