A THEORY OF STATE FORMATION AND THE ORIGINS OF INEQUALITY (*)
Carles Boix (**)
February 21, 2011
(*) Previous versions of this paper were presented at the University of Virginia, the New York
meeting of the “September Group” Princeton University, Duke University, Yale University, Stanford
University, the University of Chicago and Harvard University. I thank the comments of all their
participants, in particular to those of Sam Bowles, Dan Gingerich, Stathis Kalyvas, Carol Mershon,
Thomas Romer and Milan Svolik. I am especially grateful to the comments of Alícia Adserà and to
Teppei Yamamoto for his research assistance.
(**) Professor of Politics and Public Affairs, Princeton University. E-mail: cboix@princeton.edu.
Abstract
To explain the transition from stateless, relatively equal communities to agrarian, unequal and stategoverned societies that has taken place since about 8,500 BC, this paper offers a model with the
following traits: income-maximizing agents, who may either choose between a productive strategy
and an expropriation strategy, coordinate on peace without permanent political institutions provided
their economic conditions are relatively equal; however, as soon as inequality rises (due to a biased
technological shock), their spontaneous coordination around peace becomes unfeasible; agents sort
out into different types; and states are formed, either of a monarchical type (where the more
productive agents make a transfer to the less productive ones in exchange for permanent protection)
or a republican system (where the former invest directly on some defensive structures to deter the
latter from looting them). Those two solutions, crucially determined by military technology and the
opportunity costs of not producing, lead to distinct distributional outcomes. The formal model is
followed by a worldwide cross-sectional analysis of the sources of the ‘exogenous’ nature of the
agricultural revolution, the latter’s effects on to the formation of the state, and the impact of military
technologies on the emergence and distribution of different political regime. The paper concludes
with a brief exploration of empirical evidence (mostly related to the distribution of height patterns)
relating the type of political structure to the internal distribution of economic resources.
1
Until about 10,000 years ago, mankind lived in small, relatively equal and stateless
communities of foragers. From 8,500 B.C. onward, however, several regions of the world transited
to agriculture and sedentary human communities. In turn, the domestication of plants and animals
spurred or at least was correlated with two momentous events: the formation of the state (ranging
from small urban polities to vast despotic monarchies) and the emergence of marked inequalities in
the distribution of wealth. Those changes had long-lasting political and economic consequences, at
least until the spread of industrial technologies compressed, with a few national exceptions and
temporal reversions, the distribution of incomes within countries, and arguably triggered a process of
democratization in the last 150 years or so.
This article offers a theory to account for those joint processes of state formation and the
origins of inequality. The first two sections of the article develop a model in which incomemaximizing agents may pursue two kinds of strategies: either a productive strategy, consisting in the
allocation of their resources to the production of goods and services, or an expropriatory or
extractive strategy, which implies directing their resources to appropriate the assets or returns of
other individuals. Even though those agents may engage in conflict in one-shot interactions, over
time they may cooperate ‘spontaneously’, that is, without any permanent political institutions, if and
only if their economic conditions are relatively equal. As soon as the level of inequality rises above a
certain threshold (generally following a biased technological shock in which some individuals
benefit differently from a similar innovation), the cooperation equilibrium breaks down. In such an
unequal world, agents sort out into different types – with different payoff functions and different
strategies. Whereas the economically advantaged individuals or ‘natural producers’ have a strong
preference for production, those who do not benefit from the technological shock prefer looting.
Hence, to deter the latter, the ‘natural producers’ either invest on constructing and managing some
defensive structures (to stop the looters) or make some transfers to the ‘natural looters’ to appease
them (and to obtain some permanent protection from them). Although both solutions give birth to
permanent political institutions, i.e. the state, each strategy leads to different political regimes (self-
2
governing or republican systems versus monarchical regimes). Each political outcome, which is
strongly affected by the nature and evolution of military technologies, has, in turn, distinctive
redistributive effects. Monarchical regimes tend to generate and sustain much higher levels of
inequality than republican institutions. Still, the overall distribution of income continues to depend
on strictly economic (technological) variables too.
The third part of this article explores the empirical validity of the theoretical model.
Employing both anthropological and archaeological evidence, it first shows that foraging groups
both have no permanent political authority (i.e. some kind of leadership stably holding the monopoly
of coercion) and display very limited levels of social and economic stratification and similar
interpersonal patterns of consumption and individual wealth. Using systematic evidence across the
world and over time, it demonstrates that the agricultural revolution that took place about 10,000
years ago was triggered by exogenous factors, that is, the biogeographical conditions of each region
in the world. It then relates the timing of the birth of state institutions to the emergence of
agriculture. It concludes by linking the prevailing type of state institutions (in agricultural societies)
to the nature of military technologies.
The fourth part of the article explores the determinants of inequality. After calibrating the
model (showing how economic and military technologies as well as population and the capacity of
states shape the final distribution of income), it brings in some empirical evidence (mostly related to
the distribution of health patterns) relating the type of political structure to the internal distribution of
economic resources. Contrary to the standard research in political economy emphasizing either the
economic foundations (Marx 1848) or the political roots of inequality (Rousseau 1755[1973],
Andreski 1968), both exercises reveal that the patterns of wealth and income inequality are jointly
determined by both technological and institutional parameters.
This article makes several contributions to two areas of research in political economy: the
process of state formation and the origins of inequality. Broadly speaking, the literature on state
formation includes two main strands of thought. Institutionalist (including neomarxist) models
3
interpret the construction of political institutions as the outcome of a (voluntary or forced) deal in
which bandits offer their protection to peasants in exchange for some payment or transfer (North
1981; Olson 1993, 2000; Levi 1988; Bates 2001). Older, functionalist work sees states forming as a
response to collective action problems and to the breakdown of a cooperation equilibrium. Both
approaches suffer from several glaring weaknesses. Institutionalist models do not entertain the
possibility of states forming as self-governing polities. Functionalist approaches cannot account for
the distributive effects that accompany the emergence of political institutions. With the exception of
some historical macrosociological accounts (McNeill 1982, Tilly 1990), both literatures bracket the
effects of economic and military technologies on the overall process of state formation and on the
institutions upon which bandits and producers coordinate.
Although there is a burgeoning literature on the effects of inequality on growth (Atkinson
and Bourguignon 2000, Lindert 2000, Piketty 2000, Kahhat 2007) and on political institutions and
conflict (Boix 2003, Acemoglu and Robinson 2006, Geddes 2007, Boix 2008), much less work has
been done on the underlying causes of the evolution of inequality. From an empirical point of view
they have focused their attention to the evolution of income distribution in advanced countries in the
last three decades (Gottschalk and Smeeding 1997), suggesting partial yet still heavily contested
explanations (Wallerstein 1999, O’Rourke and Williamson 1999, Scheve and Stasavage 2007,
Gordon and Dew-Becker 2008). From a theoretical point of view, most contributions are strict
accounting exercises or limit themselves to economic variables such as imperfect credit markets
which are in turn left unexplained.1 Moreover, there is little work on the choice of political
institutions and the distribution of economic assets as jointly determined phenomena – even though
that question was a long-standing concern among classical political theorists such as Aristotle
([1988], IV, 11), Machiavelli (1531 [1970], I, 55) or Rousseau (1755 [1973]).
1
An exception is Rogowski and McRae (2008). For a review of the literature, se Kahhat (2007) and Boix
(2010).
4
1. INITIAL CONDITIONS
Set-up
To understand the dynamics that led from equal, primitive economies to complex, unequal
historical societies, consider a world populated by two types of agents, 1 and 2, each one with some
technological knowledge (for example, some natural abilities to hunt, fight, etc.). These two agents
can be thought of as individuals living together or as individuals (or households) populating some
territory. They can also be thought of as representative individuals of homogeneous groups, that is,
groups formed by agents who, because of their close ‘resemblance’ (in a sense to be made more
precise shortly) to each other, can cooperate in a stable, permanent manner.
All individuals have the same time L, which they can employ in two different types of
activities. On the one hand, they may allocate some fraction of their time L to some ‘productive’
activity (such as hunting) that generates some income yi in a standard Cobb-Douglas production
function yi=AiTiαLi1-α for i={1,2} and where A denotes the state of technology and T stands for a fixed
stock of land. 2 On the other hand, they may direct their time to predatory activities, that is, to steal
other individuals’ production. In this latter instance, they obtain (1-1/θL)yj, where yj is the return from
the productive activities of individual j (where j≠i) and θL is a technology parameter (θL >1) that
measures the effectiveness of the time allocated to extraction. Hence, the income of individual i
would be, in principle, that is, in a decision-theory setting:
ri = (1-λ) AiTiαLi1-α + λ(1-1/θL) AjTjαLj1-α
where λ (with 0 ≤λ ≤1) is the fraction of time i spends looting.
Assume that T and L are identical across all agents and define Ân = AnTnαLn1-α / AjTjαLj1-α so
that (AiTiαLi1-α / AjTjαLj1-α)= Âi and (AjTjαLj1-α / AjTjαLj1-α)=1. Then we can rewrite ri as:
ri = (1-λ) Âi + λ(1-1/θL)
2
(1)
Later I explore more precisely the nature of that productive or cooperative strategy, that is, the set of
activities (and interpersonal activities) that go into it.
5
Taking Âi and θL as given, agents i and j will choose λ that maximize their respective
incomes in the context of the strategic setting in which both agents choose between looting and
producing. The payoffs of that game will be as follows. If both agents simply produce (λ = 0), their
payoff will be Âi and 1 respectively. Under a condition of generalized looting (that is, with both i and
j looting the other side), all output not directly consumed by each agent will be destroyed. Hence,
agent i will be only able to obtain (in fact, keep) the portion she produces directly or (1-λ) Âi. In turn,
j will only keep (1-λ). Finally, if one agent loots while the other does not, the income of the nonlooter (the part not expropriated by the looter) will be reduced by some proportion due to the
destructive effects of pillaging. That is, if agent i loots while agent j does not loot, i receives the
payoffs in (1) while j gets (1-β)(1-λ). The parameter β (with 0≤β≤1) measures the destructiveness of
predation. In turn, if j loots and i only produces, i keeps (1-β)(1-λ)Âi In that instance, j gets (1-λ) +
λ(1-1/θL) Âi.
Anarchy, Equality of Conditions, and Self-sustaining Peace
To determine the conditions under which both agents will coordinate on a production
strategy, suppose that they play an infinite, repeated game, with some discount rate δ (identical for
all players). To make the analysis simple (and focused on the problem at hand), assume that players
have two strategies available to them. They can follow a trigger strategy PP, producing always until
looting occurs and then responding with looting ever after. Or they can adopt a constant looting
strategy LL. 3
3
Since (1-β)(1-λ) <(1-λ), just producing when looted is not a feasible option. The notation and solution in
this subsection partly follows Dixit (2008). On a discussion of the existing literature on cooperation in the
context of infinitely repeated games with a focus on experimental evidence, see Dal Bo and Fréchette
(2009).
6
To have sustained peace, the following conditions should take place. For player i, the value
of choosing a production strategy must be larger than looting a producer in the first period and then
facing a looting solution always ever after:
Aˆ i
1
δ
> (1 − λ )Â i + λ (1 - ) +
(1 − λ )Â i
1− δ
θL 1 − δ
Rearranging terms:
1
Aˆ i > (1 − δ )(1 − )
(2)
θL
Similarly, for player j the following inequality (where producing always is better than looting the
producer and then moving into a permanent situation of conflict) must hold:
1
1
δ
> (1 − λ ) + λ (1 - )Â i +
(1 − λ )
θL
1− δ
1− δ
Hence:
1
1
> (1 − δ )(1 − )
θL
Aˆ
(3)
i
Putting (2) and (3) together, we can conclude that continuous production will be an
equilibrium if:
1
1
> Aˆ i > (1 − δ )(1 − )
(1 − δ )(1 − 1 θ L )
θL
(4)
Inequality (4) carries with it two main implications. In the first place, it shows that, even in a
Hobbesian world, that is, in a world where there is no authority in place and players may have
incentives to raid others, it is possible for individuals to sustain peace, avoid conflict and engage in
productive activities – again without having to resort to any centralized common mechanisms of
authority. This is a result well known in the formal study of human cooperation (Axelrod 1984).
In the second place, it also shows that the non-predatory equilibrium is only possible if there
is some fundamental equality of conditions among individuals or across human communities. If Âi
becomes too large, that is, if agent i is much more productive (and, hence, better off) than agent j,
7
then the left-hand side in (4) will not hold. Agent j has no incentive to cooperate and shifts to a
looting strategy. Similarly, if Âi becomes much lower than 1, then the right-hand side in (4) will not
hold either. In that instance, it is agent i that shifts away from the production strategy. In short, in the
context of a primitive economy as the one described so far, peace is only possible if the value of
natural resources is uniformly distributed across the territory populated by i and j. 4 Otherwise, the
production equilibrium collapses and conflict erupts. 5
Open Conflict and the Exit Condition
The bounds of the level of inequality within which cooperation is feasible vary with the
discount rate and the looting technology. First, the more players value the future (i.e. the closer the
discount rate δ is to 0), the higher inequality can be without jeopardizing a production equilibrium.
Second, a predatory outcome is less likely when looting is inefficient (that is, when θL gets closest to
1). The effectiveness of looting is directly related to the military technology in the hands of the
predator. But it is also shaped by the strategies producers themselves have to reduce the value of
what a looter can steal. The efficiency of the looting technology declines (and the occurrence of open
predation does too) if producers can easily exit or move away in response to any potential
aggression, that is, if the costs of moving to a different territory are low. In fact, we know from the
anthropological literature that abandoning one’s own community and creating or joining another is a
commonly used mechanism in pre-state communities to lessen internal conflict (Leacock and Lee
1982).
4
In the model presented so far, the value of resources depends on the state of technology A. However, it
could also (and in fact it does) vary independently of the tools and skills of humans as a result of climate,
quality of land, etc.
5
Notice that the production equilibrium is compatible with higher levels of inequality if the biased shock
that generates more inequality (that is, that increases the income differential across individuals) increases
the income of the poorer individual (in the production equilibrium) as well. [DEVELOP.]
8
The feasibility of the exit option is negatively related to population densities and positively
correlated with the marginal value of land. The gradual territorial expansion of mankind across the
globe in the late Pleistocene can be explained as a rational response to manage competition for
resources. Migration was the automatic, less costly response to avoid a permanent state of open war.
However, as land filled up, the exit option became more costly and the relative value of looting
increases. According to the model, social conditions had to approximate strict equality to avoid a
predatory equilibrium.
The Nature of “Cooperation”
So far I have defined the production equilibrium by exclusion: as a set of social interactions
with no systematic looting. However, a state of nature with no open war may take several forms. In
the most stripped-down interpretation of the model, it may consist of a set of isolated individuals,
wandering alone in the forests, satisfying their needs on the spot, and clashing (or not) with each
other as a function of the parameters (their physical strength, roughly similar at the beginning of
times, and the environmental distribution of resources, more or less concentrated) of the model. In a
more elaborate application of the theory, it implies the existence of some communities of men and
women living together under a condition of relative equality. The first type of state of nature, akin to
Rousseau’s vision of the first men as a savage men, “solitary, idle and always near danger”, does not
square well with the evidence produced by anthropological research and, more recently, by
evolutionary biology theory. Human beings appear to have lived in families and bands always (even
though these groups tend to exhibit some considerable level of fluidity in primitive societies). 6 Those
social units may be partly glued by biological as well as by emotional ties (Ingold 2000). But they
are the result, especially at the band level, of optimizing individuals that join in groups to exploit
6
On human sociality as a universal condition from an anthropological point of view, see Levi-Strauss
(1961 [1955]), pp. 389-392, 397-398. For a review from the point of view of evolutionary biology, see
Hanson (1992), Hawkes (1992) and Boone (1992).
9
some economies of scale in production and/or to minimize the risks of foraging and harvesting
through resource-sharing (Smith 1987, Boone 1992). In any case, that is, regardless of the
motivations that lead to the emergence of those cooperative structures, absent any force or authority,
they are only sustainable if their members are roughly equal.
Notice then that the model can be thought as a building block in what may be labeled a
‘nested’ theory of cooperation. At the lowest (individual) level, peace is possible among a subset of
actors provided they enjoy sufficiently similar payoffs: when they do, they can form a stable, orderly
tribe, village or neighborhood. Similarly, this social unit can also sustain cooperative relations with
other human bands or tribes if the same degree of relative equality (and looting technologies) applies
at that level. Peace breaks down at the point (in the continuum of agents) where inequality of
conditions becomes ‘excessive’, i.e., inequality (4) does not hold anymore. In short, the model
explains why cooperation may exist at some but not other levels of social interactions.
2. CONFLICT AND THE EMERGENCE OF STATE INSTITUTIONS
Inequality and Sorting of Agents
As pointed above, inequality makes a cooperation equilibrium unfeasible because it alters
the ranking of preferences (and the corresponding optimal strategy) of each agent. The emergence of
inequality is the result of a process through which resources (or, more precisely, the value of
resources) become concentrated in dense and predictable patches and therefore the returns to
individuals vary depending on the territory they occupy. 7 This process can occur through at least
three paths. First, the discovery of new resources (or, simply, the occupation of new areas that have a
much higher yield): this is the case of the gradual habitation by foraging communities of the
Northwest Pacific Coast, where fishing resources were concentrated in particular areas. Second, a
technological shock, such as the agricultural revolution that I describe and exploit empirically in the
7
For a first analysis of the effects of resource concentration among animal populations, see Wilson
(1964). For its extension to humans, see Boone (1992).
10
following section, that changes the marginal productivity for some but not all territories. Finally,
population growth leading to the occupation of marginal territories and to a corresponding
differentiation in incomes between the initial core and the less valuable land.
Besides breaking the production equilibrium, inequality also sorts agents out into different
economic classes with different ‘political’ goals. Following a biased shock that increases the returns
to production of agent i relative to those of agent j, each individual pursues now very different
strategies. Whereas agent j now prefers looting, the economically advantaged agent i still has an
(even stronger) incentive to sustain a production equilibrium.
From Anarchy to Political Institutions
To overcome a generalized situation of looting, those who are better off under a production
equilibrium can pursue two alternative strategies. On the one hand, they can make a transfer (in the
form of a tribute or lump-sum payment) to agents of type j such that the latter stop looting (and
benefit from the production efforts of i). In this instance, the potential looters or bandits (those who
have not benefited from the economic shock) control (govern) and protect the natural producers from
their own explicit violence and against other potential bandits. On the other hand, the ‘natural’
producers (or agents i) may decide to make looting a much less rewarding activity (for agents of type
j) than just following a cooperative, non-violent path. They do so by setting up some institutions or
structures, such as a common army and some stable leadership, that would allow them to defend
their assets and lives against any potential bandits.
Both solutions involve the formation of some organization or structure that controls the
monopoly of violence over a given territory – that is, they involve the construction of a “state”. But
the mechanisms underpinning each solution are different. The first road to peace, which we may
11
refer to as a “monarchical solution”, follows Olson’s insight on the emergence of the state as “roving
bandits” become “stationary bandits” or landlords (Olson 1993, 2000). 8
The second strategy, which has received no attention in the modern institutionalist literature
on state formation, leads instead to the construction of a state in which the “natural” producers also
double as defenders and rulers. We may wish to call the second strategy an instance of a “selfgoverning” polity or of a republican settlement. 9 Notice that a system in which the community of
producers sets aside some portion of its income to hire an army or a leader to protect its members
(while governing themselves through republican institutions) does not constitute a case of selfgovernment or republicanism. Since the hired leader cannot credibly commit to preserve the terms of
the contract once he has been appointed and takes control of the army, such a solution ends in (or is
equivalent to) the subjection of the producers to a leader-monarch. In short, we should think of a
stable republican solution as one in which citizens have ultimate control over the means of defense. 10
We do not need to think of bandits as ‘external’ enemies only. The term of looter refers as
well to individuals who live in a given community and may try to steal, free ride on others, etc.
8
Writing from an anthropological perspective, Carneiro (1970) also offered a theory of state formation
that emphasizes the interaction of violence and exit options (the latter in turn deriving from population
density). Exit strategies and density are, however, not endogenized in his paper. As in Olson, he focuses
on the emergence of autocratic states. See Wright (1977) for a review of state formation theories in
anthropology and archaeology.
9
Olson’s (and in fact most neoinstitutionalist accounts’) unique solution explains why his explanation
about democratic transitions is ad hoc and unconvincing. He claims that democracy emerges when there
is a vacuum of power in an already-formed state in which a set of notables have roughly equal claims to
power (see Olson 2000: 28 ff.). But this state of things (i.e. the existence of balance of power) could be
equally predicated for stateless societies.
10
For a discussion of the moral hazard problems of hiring an external captain or condottiero in late
Medieval Italian cities, see McNeill (1982). The mechanisms through which citizens (or some subset of
citizens) can control defense – and so limit exploitation – are multiple. For a formal analysis of how
institutions may limit executive power, even in the context of non-democratic systems, see, for example,
Boix and Svolik (2010).
12
Individual(s) i will have then an incentive to set up some policing mechanism to dissuade
individual(s) j from misbehaving.
Monarchical Settlement versus Self-Governing Solution
Let me now characterize each political solution separately and then solve for the conditions
under which one should prevail over the other. (All this discussion clears the way to examine
analytically (in the third part, after I explore the historical validity of the model) the ways in which
those alternative paths of state formation have different consequences for income distribution and
inequality – with the monarchical solution implying some redistribution from producers to the lord
and the eventual rearrangement of income rankings within society.)
Monarchical Settlement. In a ‘monarchical’ settlement, where agents of type i make a
transfer to agents j to buy their protection, agent i’s payoff will be (1-ε)Â / (1-δ), where ε denotes the
transfer extracted by agent j, with 0≤ε≤1, and all time is now devoted to production. In turn, agent j
receives, provided he follows a non-looting strategy (which now includes an effort to protect
individuals of type i against other potential bandits), a transfer from the producer in proportion to the
time λ spent governing (as well as any payoff from his own production, if any): [(1-λ)+(ε-γ)λÂi] / (1δ), where γ is the portion that the bandit-lord spends in governing and protecting the producer and
0<γ≤ε.11
11
In a monarchical state the bandit has the monopoly of force and those that are ruled do not retain any
armed force to resist the ruler. As a result, the extraction rate ε will be set by the monarch at the level that
maximizes his income. In other words, individuals of type j cannot credibly commit to any lower ε than
their optimal choice. The extraction rate will increase with the ‘administrative’ efficiency of the state.
Second, it will also vary with the tax elasticity of output and with asset specificity (Boix 2003): the higher
the mobility of assets, the less punitive the level of extraction by the lord.
13
Self-Governing Institutions. In a self-governing system the producers themselves take
steps to defend their assets and lives against bandits, that is, they have to spend some fraction of her
time to set up a military or defense structure (such as building a wall or a watchtower to observe the
horizon). That amount of time will depend on the efficiency with which it is employed to deter any
looter j from pillaging the producer. The level of efficiency will be a function of the military
technology in the hands of the producers (relative to the military technology of the looters).
Therefore, the payoff of those agents of type i (or a community with individuals i such that all have
an incentive to cooperate) that decide to defend themselves is [(1-(λ/θD ))Âi]/(1-δ)], where λ is the
time spent in defense and θD is the efficiency of the technology with which producer i defends
himself against potential bandits – and where 0≤λ≤1 and θD >λ. Agents i keep the fraction of
production not spent in defense. As i’s defensive capabilities increase, the producer can spend more
time generating Y=YAiαLi1-α.
Looked at from the point of view of the potential looter, the purpose of creating a defense
structure is equivalent to the principle of inflicting some cost on j to push the latter into peaceful
behavior. In other words, agent i must choose a parameter of defense θD such that j has no incentive
to exploit the producer. Hence, the j’s payoff under a successful self-governing or republican regime
will be 1, that is, j will devote all his time to production and none to looting.
Choice of Institutions. Once the level of inequality disrupts the possibility od spontaneous
coordination around peace, the natural producers choose between establishing a self-governing state,
giving up their rights to a tyrant (a ‘stationary bandit’) or engaging in a looting strategy. In turn,
agents j must decide whether to abide by the political settlement or to loot.
Under what conditions will each solution prevail?
1. In the first place, a state will only emerge if the payoffs under stable institutions (either a
tyrant or a republican structure) exceed the payoffs that come from looting the other side in the first
period and then slipping into a situation of permanent conflict. Let me examine first (in points 1A
14
and 1B) by examining each alternative separately, that is, the value of a republican solution versus
straightforward looting and the value of monarchy versus looting. Later (in point 2), I consider the
conditions under which a republican solution prevails over a monarchical solution (or viceversa)
provided order is preferred to conflict.
1. A. The ‘natural’ producers (agents i) would rather have a republican structure than looting
(provided they prefer the republican solution over the monarchical settlement) if:
(1 − λ θ D ) Aˆ i
1
δ
> (1 − λ ) Aˆ i + λ (1 − ) +
(1 − λ ) Aˆ i
1−δ
θL
1−δ
Rearranging the terms of this inequality gives us:
(1 − 1 θ L )
Aˆ i > (1 − δ )
(1 − 1 θ D )
(5)
Thus, the incentives of any agent i to move to a republican solution increase when the
alternative option of looting becomes less attractive – either because the looting technology θL
declines in efficiency, the defensive technology θD improves, or the production technology Âi
increases.
In turn, agent j will accept the self-governing structure set up by i if just producing leaves
him better off than trying the looting strategy:
δ
λ
1
 i +
(1 − λ )
> (1 − λ ) +
1− δ
θD
1− δ
Rearranging this inequality then:
θD
> Âi
1−δ
(6)
In short, j is more likely to accept the production strategy when the strategy capabilities of i
increases and when the value of i’s production declines.
Putting (5) and (6) together, a republican settlement is feasible whenever:
θD
(1 − 1 θ L )
> Aˆ i > (1 − δ )
1−δ
(1 − 1 θ D )
(7)
15
In addition to (7), self-government will only be feasible if peace without transfers is not an
equilibrium. 12
1. B. In the instance in which a monarchical solution is preferred over a republican one, the
natural producers will only accept to transfer some resources to a tyrant if that makes them better off
than looting:
(1 − ε ) Aˆ i
1
δ
> (1 − λ ) Aˆ i + λ (1 − ) +
(1 − λ ) Aˆ i
1−δ
θL
1−δ
Rearranging the inequality:
λ−
(1 − δ )(1 − 1 / θ L )λ
Âi
>ε
(8)
A monarchical regime becomes more attractive to producers when the efficiency of looters
(measures through θL) and the extraction rate ε decline and the productivity of i increases.
In turn, j will have an incentive to act as a monarch and not as a bandit if:
(1 − λ ) + (ε − γ )λAˆ i
1
δ
(1 − λ )
> (1 − λ ) + (1 − )λ i +
1−δ
1− δ
θL
Hence:
ε > (1 − δ )(1 −
1
θL
)+γ
(9)
Therefore, agents of type j will become monarchs when the extraction rate and the looting
costs increase and when the costs of governing decline.
Putting together (8) and (9), a monarchical settlement will be possible whenever:
λ − λ (1 − δ )(1 −
1
θL
)
1
1
> ε > (1 − δ )(1 − ) + γ
θL
Aˆ i
(10)
As in the case of a republican settlement, in addition to (10), a monarchical settlement will
only be feasible if peace without transfers is not an equilibrium. 13
12
This condition takes place, following (3), when Âi>1/[(1-δ)(1-1/θL)]. It is possible to show that there is
a broad range of values for which both the latter inequality and (7) hold at the same time.
16
2. For the space in which a state (either monarchical or republican) may take place
(according to the conditions spelled out in 1.A and 1.B), the producer (agent i) will prefer a
republican over a monarchical solution whenever:
(1 − (λ θ D )) Aˆ i (1 − ε ) Aˆ i
>
1−δ
1−δ
Simplifying the expression:
ε >
λ
θD
(11)
According to inequality (11), the political solution depends, given a fixed time λ devoted to
looting, on the rate of extraction ε. The higher ε is, the higher the incentive to establish a republic.
The political regime will be also a function of war technology. If producers are superior or even
relatively equal to looters at war, the former will be able to deter any predator or set of predators and
therefore will associate in human communities where decisions are made in a consensual manner or
where, at least, a broad section of the population has some impact over politics. However, as soon as
θD falls, that is, as soon as looters acquire some strong comparative advantage in the use of force,
monarchical regimes will become the prevalent form of government. That may happen for multiple
reasons. Looters may control a particular type of weapon or develop a new set of military tactics that
are particularly effective at waging war. More often, the invention of new weapons (such as swords
or horse chariots) requiring considerable training and expertise foster the process of specialization
and professionalization of war-making. The opportunity costs of self-defense among producers
escalate. By contrast, those individuals that engage in predatory activities gain in power and
effectiveness. They form a separate caste of warriors that encroaches upon the self-governing
institutions preferred by the producers and that establishes centralized states with highly extractive
fiscal systems.
13
Again, there is a wide range of values that make these two conditions (and thus a monarchical regime)
feasible.
17
Notice that, if the producer sets up a republic, the potential looter j will abide by the solution
since, by definition, a republic is only possible if producers have the actual military capacity to deter
looters from pillaging them (and, again, this deterrence strategy still is preferable to any other
solution).
If the producers are, instead, better off under a monarchy, agents of type j will not accept the
monarchical settlement if their payoff under a republic is larger than the monarchical transfer (1-ε)A
– with the looting alternative precluded by our assumption that inequality (7) holds. In that case, the
producers will have to increase ε to the point that monarchy becomes attractive to j (provided that,
even after that increase in the extraction rate, a republic would still leave agents i worse off than the
monarchical solution).
An Extension: The Possibility of Imperial Republic. In addition to establishing a selfgoverning structure to pursue a purely defensive strategy, producers i may decide to engage in an
offensive one, both geared toward defending their land and attacking the looters. The offensive
strategy costs an extra fraction of i’s production above the price paid to simply defend their own
territory. Therefore, since it implies a lower direct output for i, we can denote the offensive
technology parameter as θO with 0≤θO≤θD . 14
Since the use of an offensive strategy implies that agents i will apply sufficient force to make
individuals j spend their time producing even when they experience some looting from i, the natural
producers will follow that strategy (to establish an imperial republic) only if the benefits of looting j
are larger that the portion of output lost in upgrading the military strategy from a defensive into an
14
It seems plausible to think that even when the main endeavor of these agents is production, they still
need to pay always some minimum costs of defense θD to be ready to move to the fully militarized
strategy. As a matter of fact, if θD were equal to 0, then government institutions would only appear when
individuals of type j chose a looting strategy. Otherwise, if individuals of type j did not loot, everyone
would simply cooperate spontaneously with no permanent structure governing them. This does not seem
to be realistic.
18
offensive one. This will depend on two factors. First, the incentives to set up an imperial republic
will decline whenever the offensive costs θO increase with respect to the defensive costs θD. Second,
they will also fall the more productive the agents of type i become with respect to the agents of type
j. The latter proposition derives from the fact that, as the i’s become wealthier, the opportunity costs
of any expansion become higher. Or, to put it in slightly different terms, the more marginal lands and
persons (of type j) are, the less prone their (richer) neighbors i will be to attack and subject them. 15
3. HISTORICAL DISCUSSION
Egalitarian, Pre-state Communities
Until about 8,500 BC all mankind lived in bands of hunters and gatherers. Since
archaeological research only offers rather scant information about the nature and patterns of social
interactions in those pre-state communities, we are forced to rely on contemporary anthropological
research, mostly on foraging communities, to assess the nature of simple communities. 16
With the exception of the fishing communities of the Northwest Pacific Coast, which
showed considerable social differentiation, mostly related to a pattern of strong spatial concentration
of resources in discrete areas, foraging communities are small in size (the sum, at most, of a few
extended families). 17 They are also internally equal. Economic differences within bands are either
15
Mathematically, i will choose to follow an offensive strategy if:
Simplifying the expression shows that the inequality holds if:
(1 − λ θ O ) Aˆ i + (λ / θ O ) (1 − λ / θ D ) Aˆ i
>
1−δ
1−δ
λ
λ
λ
>(
−
) Âi
θO θO θ D
This will happen as either Âi becomes closer to ) or θO approaches θD (which in turns makes the
expression in the parenthesis close to 0).
16
For a discussion of the extent to which current ethnographic evidence may be employed to make
inferences about past foraging communities, see Headland and Reid (1989) and O’Connell, Hwakes and
Jones (1988).
17
Northwest pacific communities were also characterized by the construction and ownership of
sophisticated equipment, such as complex fish traps, which involved considerable labor (Rowley-Conwy
2001).
19
absent or very limited. Food and, particularly, meat distribution is strictly egalitarian (except, in
some communities, for very large preys) (Hawkes 2000). Differences in nutrition over the life cycle
are minimal (at least within each gender) (Kelly 1995). Success in hunting is tracked by everyone
(Hawkes 2000) and some social recognition is granted to the good hunter (Turnbull 1965; Kaplan &
Hill 1985). But foraging communities have strict social norms that prevent the hunter from owning
the meat he has hunted and status recognition is extremely transient (Weissner 1996, Erdal and
Whitten 1994). Individual success seems to lead at most to easier access to a few goods such as
sexual partners. However, there is too much variability in hunting performance over the medium run
to lead to permanent social distinctions (Hawkes 2000). According to recent work comparing 21
foraging, pastoralist and agricultural communities, inequality is extremely low among foragers
except for embodied wealth (measured in terms of physical strength, hunting skills, etc.) (Smith et al.
2010). The intergenerational transmission of wealth is also low except for traits that can be explained
in strict genetic terms. To the extent that there is some correlation in genetic endowment across
generations, it does not come from more and better nutrition provided to the children of the best
endowed parents but rather from matching between good hunters and more hardworking women
(Hawkes 2000). The existing archaeological evidence for Paleolithic sites seems to confirm similar
patterns of nutritional equality and little material differentiation (Formicola 2007; Vanhaeren &
D’Errico 2005).
Simple foraging societies lack any clear, stable authority structure and certainly no stable
organization (or group of individuals) holding the monopoly of violence in a given territory.
Decisions affecting the band are arrived at through discussion in which all adults participate
(Turney-High [1971]: 61-73; Silberbauer 1982). Even when there are some patterns of leadership,
leaders have no formal authority and act as mere referees among different individuals or families or
spend substantial time negotiating with, cajoling or persuading other members of the tribe (Clastres
1972; Lee and Leacock 1982; Lee 1982). And although threats and actual violence are certainly
employed within the tribe, they happen in a sporadic or at least non-institutionalized manner
20
(Clastres 1972, 1974; Kelly 2000). In short, the structure and underlying dynamics of foraging
societies match the model in section 1. A pattern of relative equality in foraging groups underpins
the outcome of “spontaneous” social cooperation within each tribe or, to employ Clastres’ terms, the
outcome of “non-state politics”.
Equality is the result of a particular (uniform) distribution of resources in the environment
(in conjunction with a specific technology of production). But the outcome of social cooperation is
the result of systematic, deliberate and painstaking efforts directed at maintaining peace among
individuals. At the end of the day, the production equilibrium is just one of the two equilibria that
may take place in the repeated PD game discussed in part 1. Violence, looting and exploitation can
erupt at any time, with catastrophic consequences for everyone, especially given the constraints
imposed by a rather harsh ecological environment. Hence pre-state communities need to spend
considerable efforts at equalizing material outcomes and social status across individuals.
The “creation” (or maintenance) of equality in pre-state communities does not result from
having a shared ideology accepted and followed out of idealistic convictions. It has none of the
romantic qualities imagined by Marx and Engels in their depiction of primitive communism or later
attributed to foragers by a certain anthropological tradition. It is simply the result of the “behavior of
sociable and self-interested individuals whose motivations include a strong desire to get enough for
themselves coupled with a strong desire to make sure that no one else gets more than they do” (Erdal
& Whiten 1994: 177). In fact, the distribution of food is often conflictual, involving arguments,
yelling and clear signs of jealousy and envy. Any individual deviation from the mean is quickly
noticed and then hammered out through mocking, pleading and shaming. Writing about the San,
Wiessner notes that “[it cannot] be argued that !Kung have little interest in material possessions.
Most possessions … are highly desired; and many !Kung are really torn between the desire to
accumulate goods and the desire to remain within a secure system of mutual help.” Hence,
individuals may work hard and even try to accumulate some material possessions only to “come
under more and more pressure to give them away in hxaro, and finally give in and redistribute them”
21
(1982: 81-82). Similarly, hunting parties are followed by an elaborate set of practices directed at
leveling down the successful hunter. The latter rejoins the band announcing the yield of the hunt
modestly, almost in a hush. His entry is then followed by the systematic efforts of the band to
“downplay his merits” through teasing and mocking, to stress the randomness of the success, and to
“emphasize his duty to provide meat for others” (Wiessner 1996: 179). 18 Across all simple societies,
from the Inuit Eskimos to the !Kung in the Kalahari, the ideology and practice of equality turns
around denouncing and avoiding two capital sins: stinginess, that is, “to hoard one’s goods jealously
and secretively, guarding them ‘like a hyena’” (Lee 1982: 52); and arrogance, which “is actually
dangerous, since according to the !Kung ‘[someone’s] pride will make him kill someone” (Lee 1982:
54)
Maintaining equality implies exercising an inordinate level of psychological repression upon
each and every member of the community. As stressed before, the suppression of individual
differences is often done very openly: by the use of constant deprecation toward oneself, by
employing a piercing irony toward others, and by constantly begging the more successful members
to engage in the proper behavior of sharing (or what someone has labeled “institutionalized
stealing”). But in some communities repression is above all about structuring the inner motivations
of every member of the group: although relationships between parents and children are hardly
authoritarian and although the latter normally enjoy a very playful infancy, children are brought up
in the expectation that they will uphold the tight social norms of equality and conformity in place.
Accordingly, as Briggs writes about the Inuits, “in a society in which the expression of hostility is
very stringently controlled (…), it is more than likely that people project their own suppressed
hostility onto others and, knowing that they themselves feel violent, will easily suspect others of
murderous intents” (1982: 116).
18
Similarly, Lee (1984) for the !Kung, Woodburn (1982: 440) on the Hadza, Hararo (1981: 536) on the
Mbuti, Clastres (1972) on the Ache, Lothrop (1928: 422) on the Ona, Balicki (19xx: chapter 9) on
Eskimos.
22
Those societies, characterized by repressed fear and constant suspicion, witness unexpected
explosions of individual anger, resulting from rather trivial, almost childish disputes with a marked
“noninstrumental manner” (Knaupf 1991: 400). According to the existing anthropological research,
violence is unrelated to any struggle for material goods or political control. In turn, male competition
for females only explains part of the conflict and with different success across groups. In addition to
individual disputes and killings, there is considerable collective violence: individuals deemed to
deviate from the boundaries of appropriate behavior are prone to accusations of black magic and
witchcraft and to some kind of socially sanctioned execution (Knauft 1987, 1991). Violent deaths
are, as a result, extremely high in pre-state societies. The annual homicide rate, which stands at
around 20 to 30 individuals per 100,000 in American inner cities, has been estimated to approach
around 300 individuals per 100,000 among Agta Pygmies and over 400 per 100,000 among the
Copper Eskimo and Papua-New Guinea’s Gebusi (Knauft 1987; Headland 1989; Gat 1999). About
25 percent of adult males die from a violent death on average in foraging societies. That proportion
matches the percentage of buried skeletal remains from the Paleolithic showing traces of violence
(Kelly 2000; 155).
Nonetheless, that level of lethal conflict does not jeopardize social stability. Homicides
committed by a single individual remain largely constrained. They never escalate into a general
conflict pitting one family against the other in the social group. 19 As Balikci (1970: 182) points out
in his study on the Netsilik Eskimos, because “every murder signified the loss of a highly needed
seal hunter”, the community always intervened to stop any revenge that could lead to a chain
19
Homicides (committed to revenge a previous crime) are hardly interpreted as an injury to a whole
group and do not generally lead to the collapse of social interaction within a given human band. In
foraging communities, “when felt anger or ill-feeling is expressed in interpersonal violence, the
expressive action typically runs its course (…) and may actually culminate in murder. However, the
violence that occurs is specific, not generalized, and it does not escalate beyond a sequence of events that
encompasses homicide followed by execution of the killer. Typically, a murder is an isolated event with
no sequel” (Kelly 2000: 42-43).
23
reaction. If generalized violence becomes unavoidable, most foraging bands manage it through a
process of fission: a section of the group secedes and migrates to a new location, where it selforganizes again along the standard patterns of relative equality and non-institutionalized politics. 20
Transition to Agriculture
The domestication of animals and plants about 11,000 years ago put an end to a world solely
populated with foraging communities. The invention of agriculture had two effects. It increased land
productivity: whereas a family of hunters and gatherers may need several square miles to survive, a
household of irrigation agriculturalists may live with less than one hectare (Bellwood 2005: 14-19).
It raised land productivity in a non-uniform manner across territories, generating a pattern of
inequality across individuals and human communities (and probably within human groups also): as
agriculture spread out, initially homogeneous regions (enjoying the same marginal productivity as
hunting areas) acquired a differentiated resource gradient ranging from a ‘core’ of rich lands to a
‘periphery’ of very marginal quality.
The causes behind the adoption of agriculture have been thoroughly debated among
scholars. A first strand of the literature explains the domestication of plants and animals as a
response to the declining marginal productivity of hunting and the related Malthusian constraints
faced by growing populations of hunters and gatherers (Flannery 1965; Binford 1968; Cohen 1977).
A second set of researchers interprets agriculture as a technological improvement that happened as a
result of a long process of learning (Rindos 1980). A third line of research traces it back to a
momentous change in cultural norms among foraging societies (Bender 1978).21 Regardless of the
ultimate causes of the agricultural revolution, it is obvious that the transition to agriculture could
20
For an analysis of the exit option in the hortoculturalist society of the Yanomanos, see Chagnon (1997).
For a broader conceptual analysis of the effect of strong exit options on income distribution and political
structures, see Hirschman (1981), chapter 10.
21
For general reviews, see Watson (1995), Bar-Yosef and Meadow (1995), Bellwood (2005), Barker
(2006).
24
have only taken place in those areas that were characterized by quite precise geographical,
environmental and climatic conditions. As pointed out by Diamond (1997), the agricultural
revolution materialized in those regions of the world that had enough plants and animals suitable for
domestication and the proper climate to exploit those species.
Partly building upon seminal empirical work by Hibbs and Olsson (2004) and Olsson and
Hibbs (2005), Table 1 shows that most of the variation in the time at which different parts of the
world transited to agriculture was indeed related to the set of biological and geographical conditions
of each of those areas. That result implies that the causes of the transition that led to the social and
political consequences (inequality and state formation) formalized in Section 1 were exogenous to
those outcomes.
The estimations in Table 1 are of two kinds. Models 1 through 3 examine the impact of strict
geographical conditions on the number of domesticable plants and animals across the world. Models
4 and 5 estimate the effect of those same geographical conditions on the years it took each
geographical unit to transit to agriculture. The units of analysis are the geographical quadrants
defined by 10 degrees in latitude and longitude (starting at the intersection of the Equator with the
Greenwhich meridian) for which there is some land mass. There are 234 such observations – 203 if
we exclude the Antarctica. 22 The number of species suitable for domestication are taken from Olsson
and Hibbs (2005) and come for ten separate regions of the world.23 The number of domesticable
animals ranges from 9 in the Middle East to 0 in Iceland. The number of plants goes from 33 to 0.
The years to agriculture are the years it took agriculture to appear since the beginning of the
Holocene (9,500 BC). 24 The data is built employing the information gathered in the surveys written
22
In the Olsson-Hibbs work, the unit of observation is the contemporary state.
23
Those regions are: Near East-Europe-North Africa, East Asia, Southeast Asia, Sub-Saharan Africa,
North America, Central America, South America, Australia, Pacific Islands and Iceland.
24
For a discussion on whether to code the origins of agriculture following either the first evidence of
plant (and animal) domestication or the moment at which horticultural practices give way to intensive
agriculture, see Shenk et al. (2010) and Thurston and Fischer (2007).
25
by Bellwood (2005) and Parker (2006). For those areas where agriculture has yet to develop I assign
a value of 11,500 years (9,500 plus 2,000 years).
The geographical conditions are measured through four variables:
1. Climate, measured following Köppen’s system of climatic classification and ranging from
1 (worst climate for agriculture) to 4 (Mediterranean and West Coast climate). I code each unit of
observation by looking at the geometrical center of the quadrant.25
2. Latitude of the geometrical center of each observation. I also add the square of latitude to
capture any potential non-linearities in the effects of latitude.
3. Major axis of continent, that is, longitudinal degrees between the extreme eastern and
western points of the continent divided by the distance in latitudinal degrees between the extreme
northern and southern points of the continent. The axis ratio goes from 0.1 (in the Pacific Ocean) to
3 (for Asia).
4. Island, that is, whether the unit of observation (or most of it) belongs to an island or not.
Both climate and latitude approximate the environmental conditions most favorable to
agriculture. The axis ratio measures the fact that, as emphasized in Diamond (1997), a predominant
East-West orientation speeds up the diffusion of agricultural techniques within continents since new
agriculturalists do not need to modify the received plants to new climatic conditions. The dummy
island is a second proxy to tap the effects of oceans as barriers to the adoption of agriculture.
[Table 1 about here]
The geographical variables of climate, axis and island are statistically significant, behave in
the expected direction and together explain about 55 percent of the variance in the number of
animals (Model 1), plants (Model 2) and a composite of the two (Model 3). A one-point shift in the
25
The coding is as follows: 1 for tundra and ice (climates of type E in Köppen’s classification), dry
tropical climates (climates of type B) and subarctic climates (Dc and Dd in Köppen’s); 2 for wet tropical
(climates of type A); 3 for temperate humid subtropical and continental areas (types Caf, Caw, Da and Db
in Köppen’s system); and 4 for dry hot summers and wet winters (types Cb, Cc and Cs).
26
climate variable changes the number of animals by 0.5 and the total of plants by 1.5. The axis ratio
has a strong impact on the number of species that can be domesticated: the maximum value of 3
implies about 11 animals and 24 plants. Being an island reduces the number of domesticable plants
and animals by 3 and 10 respectively. Finally, latitude has some effect on the number of plants.
Models 4 and 5 report the impact of the environmental conditions on the time to agriculture
– with Model 5 excluding the cases of Antarctica. All the variables are strongly significant and the rsquared is 0.54. A shift in the climate index from the worst to the best conditions leads to the
introduction of agriculture 2,800 years earlier. The size of the coefficients for axis ratio and island
underscore, in turn, the importance of geographical barriers to explain the agricultural revolution. All
other thing equal, agriculture spread 2,000 to 2,500 years earlier in Asia than in America. The sea
delayed the process of diffusion by 1,500 to 2,250 years. Figure 1 displays the correlation between
the time at each agriculture was introduced and the composite index of biogeographical conditions
(the abbreviations correspond to the contemporary country that matches the geometrical median of
the area and so there could be more than one observation represented by the same abbreviation). 26
[Figure 1 about here]
State Formation
The process of economic differentiation of individuals and territories (due to a biased
technological shock such as the agricultural revolution or the occupation of new lands) is a necessary
but not sufficient condition for the emergence of states. The introduction of political institutions
depends on the development of some permanent military structures, either directly by the ‘natural
producers’ or provided by a ‘condottiero’ or pacified bandit. In turn, to set up those structures, that
is, to establish some kind of political hierarchy, the technologies of war must grow in their degree of
sophistication: if all individuals have equal access to very simple weapons (such as rocks and sticks),
26
The index is an equally weighted average of climate, latitude, axis and island (set at their relative
values with respect to the maximum value in each variable).
27
they have no incentives either to associate together and spend some time in military training or to
accept the tyranny of a bandit.
According to the existing archaeological research, political institutions emerged after (and
never before) the transition to agriculture (cf. Thurston and Fischer, ed. 2007, and the chapters
therein). In the most investigated region where agriculture appeared independently, the Middle East,
there were several villages with an estimated population in each one of them of three to four
thousand inhabitants in the southern Levant already in the seventh millennium before Christ (Kuijt
2000). Although there are some traces of labor specialization, most studies agree that households
were the basic economic units in the agricultural Neolithic and that they were “homogeneous with
regard to wealth and status” (Voigt 1990: 7). The existing non-domestic structures, such as the
defensive walls and the temple shrine of Jericho, from about 6,500 BC (Yadin 1963, Finer 1997),
point to the existence of some collective authority. But they do not appear to embody any status
differentiation (Monahan 2007).
The first and more systematic historical records attesting the formation of states (and a much
more hierarchical political structure) only appeared later in time, at around 3,200 BC, that is, a few
thousand years after the domestication of plants and animals, mainly because writing was only
invented at the end of the fourth millennium before Christ. As discussed later, it is not coincidental
that they appear with the use of metals to build weapons. All the first documented states invariably
formed in areas that had first transited to agriculture. At the end of the fourth millennium BC there
were a few city states, with several thousands of inhabitants, a centralized political authority and
fortified walls, in southern Mesopotamia. Egypt became unified under a single monarch at around
3,000 BC. By the end of the third millennium several palaces were built in Crete, spawning the
Minoan civilization. A few hundred years later continental Greece witnessed the emergence of
several monarchies within what has been called the Mycenaean civilization. The Harrapan culture,
with large urban agglomerations and fortified structures, flourished in the Indus valley in the middle
of the third millennium BC. The first firm evidence of a state structure in East Asia has been put at
28
around 1,850 BC with the Shang dynasty governing northeastern China. In America, urban
settlements and state structures developed in the two main cradles of agriculture: in Mesoamerica
about two thousand years ago and in the Andean area around AD 500-700 or perhaps earlier.
[Figure 2 here]
More systematically, Figure 2 explores the relationship between the spread of agriculture
(horizontal axis) and the appearance of state institutions (vertical axis) in all the geographical
quadrants of the world (as defined earlier). A state is defined by the existence of a specialized
organization with the quasi-monopoly of coercion over a well defined territory. I code an area as
having a state if there are contemporary writing materials that report the existence of those structures
or if, absent writing records, there are sufficiently large fortified structures that point to the existence
of armies and states. I employ the information provided in Kinder and Hilgeman (1974), Mann
(1986) and Finer (1997) and several regional histories to date the approximate century at which
political institutions formed. In coding the emergence of states I take a conservative approach: for
example I date the emergence of states at around 3,000 BC in Mesopotamia and the Near East (when
writing records appear for the first time) even though Jericho seemed to have had some fortified
structures a few thousand years earlier. Pacific islands are not coded because it is unclear whether
(and when) complex tribal chiefdoms were born before Europeans explored that area.
Figure 2 reveals two main empirical patterns. First, the transition to agriculture always
preceded rather than followed the formation of states. Second, states came into being with a temporal
lag with respect to agriculture. This temporal gap, which shrank over time, must be related to two
facts: first, the dissemination of intensive agriculture (at around 4,100-4,000 BC according to
[Barker 2006]); second, a shift in military technology. Until the end of the fourth millennium, men
employed stone, a material that was too cheap and easily available to give any strong advantage to
any of its users, to build weapons. The introduction of copper helmets and swords revolutionized the
dynamics of war – it certainly coincided with the appearance of the first Mesopotamian city-states. A
few hundred years later, the invention of bronze, an alloy of common copper and tin, exacerbated
29
those trends toward more military specialization (and the creation of states) for two reasons: the
hardiness of bronze gave a considerable military advantage to its users; the scarcity of tin and its
very localized sources “made it a substance on which it was easy to levy high market prices and
heavy transport tolls and taxes at the point of delivery” (Keegan 2004: 238), further fostering that
process of concentration of military might among certain strata.
[Table 2 here]
Table 2, which estimates the relationship between the transition to agriculture and the
formation of states, confirms the previous discussion. Models 1 and 2 estimate the impact of
biogeographical conditions on the birth of states, with and without Antarctica respectively. All the
variables are strongly significant and operate as expected. Models 3 and 4 examine the relationship
between year of transition to agriculture and year of birth of political institutions (again with and
without Antarctica). The relationship is extremely strong with and r2 around 0.6. Since one can claim
that diffusion effects may be important the process of state formation, Model 5 simply looks at those
cases where political institutions formed ‘originally’ in each area. The explained variance is about
the same.
Violence and Population Migrations
Besides linking the formation of states to the agricultural revolution (and military
technologies), the model in Section 1 sheds light on the origins and direction of violence, with the
poor, non-agricultural populations looting the technologically advanced, sedentary societies that
emerged after the domestication of plants and animals. That prediction turns out to be a very strong
regularity in human history. Populations in peripheral, less rich lands have tended to breed much
more war-prone populations than fertile lands. Ancient Mesopotamia and Egypt, the first centers of
agriculture in the Middle East, withstood successive waves of invaders originating in the Caucasus
and the Asian steppes such as the Hurrians in the third millennium and the Hyksos in the late second
millennium. The Roman Empire fell under the pressure of Germanic tribes. Medieval Europe
30
endured the attacks of periphery populations such as the Vikings, Slavs, Turks and Mongols.
Similarly, China was raided and at times governed by several steppe tribes. In Mexico and Central
America, once-periphery groups such as the Aztecs came to dominate the core lands of the region.
Military Technology and Type of Political Institutions
As discussed in Section 1, the type of state, ranging from a ‘self-governing’ or republican
constitution to a monarchical or dictatorial regime, depends crucially on the efficiency θD with which
the producers can defend themselves against potential looters.27 To examine the impact of war
making on the type of state institutions, I now look at the political consequences of what have been
considered five key technological innovations in military weaponry: bronze weapons, the horse
chariot, the invention of iron, the stirrup and firepower arms. 28
As already mentioned before, the introduction of bronze helmets, swords and ax sockets at
the end of the third millennium B.C. led to the collapse of the Mesopotamian city-states and to the
formation of the first big monarchical states in the Middle East – Sargon of Akkad, for example,
27
In addition to the type of war technology, the costs of self-defense for producers may be affected by the
levels of competition among looters. A bandit-lord who has to fend off the assault of other agents of his
same type will have fewer resources left to enslave other communities of producers. As emphasized by
Hansen (2000), many (if not most) of the thirty city-state systems that he has identified emerged in the
margins of empires or kingdoms with insufficient means to exercise complete control over their nominal
territories. For example, after the collapse of the Carolingian empire, the exercise of political authority
was substantially weak in the decentralized areas of the Lotharingia: that may explain why European
cities emerged mostly in the axis Flanders-North Italy already in the early Middle Ages (Dhondt 1976).
28
Although these technological innovations do not exhaust the list of invented weapons (since there are
other tools such as the bow, fortifications, etc.), they are arguably the most important in military history
(Andreski 1968, Keegan 2004). Besides any strictly technological innovations, there have been
considerable organizational and strategic changes in war making. I do not consider them directly for
several reasons: they are often linked to technological changes (for example, the hegemony of cavalry is
directly related to the introduction of the stirrup); they are harder to trace and more volatile in nature
(with some of them related to the military creativity of a particular general); and they are arguably less
exogenous to politics than pure technological changes.
31
controlled an empire of roughly the size of modern Iraq. The predominant use of bronze weapons
was associated with a sharp division between a warrior aristocracy and a peasant class in Ancient
Greece (Andreski 1968: 43-44).
The introduction of two-wheeled horse chariots probably had an even stronger impact on the
kind of political institutions. The invention of the spoked wheel and of light chariot bodies combined
with the use of fast horses (in place of the former onagers) radically altered war making at the end of
the second millennium B.C. The speed of transportation was multiplied by ten to about 20 miles per
hour. Military effectiveness at the battle camp also increased extraordinarily. Since a single chariot
crew (one driver and one archer) could kill about six men a minute circling at a distance of 100 to
200 yards, ten chariots (or twenty men) could cause over half a thousand casualties in about ten
minutes. The pastoralist peoples in the margins of the Eurasian steppes were the first to employ the
horse chariot – they could easily apply all their riding and hunting skills to these new technologies of
war (Keegan 2004: 159-66). Attracted by the much richer agricultural lands to the South (and East),
they launched successive waves of attack: the Hyksos penetrated Egypt, the Hurrians and Kassites
entered Mesopotamia, the Aryans conquered India and certain tribes originating in the proto-Iranian
heartland in the Altai established China’s Shang dynasty. The success of the chariot peoples was
generally short-lived: the Assyrian and Egyptian elites copied their war strategies and restored their
control over their own lands. But the horse chariot led to the consolidation of a set of ‘feudal’ states
with a narrow aristocracy of warriors exercising full control over their subjects (McNeill 1982). The
Old Testament provides us with direct, written information on this transformation in Israel. During
the period of the Judges, Israel’s army was essentially a militia “made up of warriors from individual
tribes who were summoned to battle only in emergency” (Yadin 1963: 255) and the internal
organization and equipment of each tribal unit remained in the hands of each clan. In response to the
attacks of the peoples of the sea, David and his descendants professionalized its army, introducing a
regular army and a body of heavily armed charioteers, and effectively constructing a centralized
monarchy in the process.
32
Whereas the use of bronze weapons and the horse chariot reduced θD or the military
effectiveness of producers, the discovery of how to make weapons out of iron allowed a “relatively
large proportion of the male population [to] acquire metal arms and armor” (McNeill 1982:12),
mostly because there is a large supply of iron ores in the world (about 4 percent of the earth mass is
iron ores). Although with some lag, this led to relatively more egalitarian political and social
structures. After the expulsion of the Etruscan kings, iron cheapened the access to arms, made
infantry central in war and secured the political ascendancy of Roman rural strata – to the point that
only those who were too poor to equip themselves for military service were practically deprived of
the vote” (Andreski 1968: 54). 29 In Greece, where the irregularity of the terrain (and the type of
crops) made the use of chariots rather ineffective [check Victor Hanson], the spread of iron weapons
broke the hegemony of the bronze-wielding aristocracy and equalized conditions. As pointed by
Aristotle in his Politics, “where the nature of the country can admit a great number of horse, there a
powerful oligarchy may be easily established”, “where the troops are chiefly heavy-armed, there an
oligarchy, inferior in power to the other [the calvary-dominated one] may be established” and,
finally, “the light-armed and the sailors always contribute to support a democracy” (Book 6, Part 7).
Thus, whereas Athens was a maritime republic, Thessaly, where the cavalry was always the main
army, remained wholly unaffected by democratic movements (Andreski 1968: 45).
Widely employed in China by the fifth century AD, the stirrup reached Japan during the
following century and Eastern Europe by the seventh century. By the ninth century the stirrup and,
with it, heavy cavalry were fully widespread in Europe. Given the high cost of equipping one knight,
the rise of the armored horseman had to tip the balance again in favor of the specialized warrior.
Under the Sassanid dynasty and after the introduction of heavy protective armor, peasants were
reduced to harsh servitude. Under the T’ang dynasty the situation of the Chinese peasant also
worsened considerably (Andreski 1968: 46-49).
29
Even when the armed men had the right to participate in politics, the vote was weighted according to
the costs of the armament, that is, it was biased in favor of the cavalry and the heavy infantry.
33
Whereas the impact of heavy cavalrymen operated through cohesive armies and stable
imperial bureaucracies in China, in Europe it took place in a rather fragmented and conflict-ridden
continent. The geographical diversity of Europe and the fact that the effectiveness of the stirrup and
the heavy cavalry are heavily dependent on ground conditions afford us an excellent opportunity to
test the effect of war technologies on state structures. In the broad plains of continental Europe,
where heavy cavalry became the dominant type of military force, feudalism replaced previous forms
of social and political organization: that transition was completed after Charlemagne in France and
Germany; in Catalonia by the tenth century; in England with the Norman invasion; 30 in Poland after
the gradual clearance of forests and morasses facilitated the movement of horses; in the lowlands of
the Balkans with the invasions of the Avars, Bulgars, Magyars and Petchnegs; in Denmark by the
beginning of the lower Middle Ages (Andreski 1968: 59-61, 66-67; Rogowski and McRae 2008). By
contrast, feudalism did not succeed in those terrains where heavy cavalry was ineffective. Infantry
prevailed in Sweden due to the density of forests and in Norway, Switzerland and the highlands of
the Balkans due to their mountainous nature. There was never serfdom in Sweden, the only country
in Europe where representatives of the peasantry sat in parliament. The inhabitants of the high Swiss
cantons always governed themselves through communal assemblies. And in the highlands of Serbia,
Bosnia and Montenegro “the semi-nomadic mountaineers [lived] under the tribal democracy
tempered by patriarchy” without any ruling nobles (Andreski 1968: 67). 31 According to Ferejohn
and Rosenbluth (2010), medieval Japan presented the same pattern: mountain villagers and islanders
could defend themselves well against the encroachment of horsemen and of the central state until
late in time.
30
English feudalism declined after 1300 – arguably after the English learned the use of the long bow in
their wars against the Welsh (Andreski 1968: 64-65).
31
In Japan feudalism crystallized with the expansion of heavy cavalry – but faced too pockets of
resistance in mountainous areas (Ferejohn and Rosenbluth 2009).
34
The cannon triggered another shift in the internal distribution of political power. The need to
generate economies of scale encouraged the formation of large states with a strong, absolutist crown
and led to the demise of the old class of feudal lords (Anderson 1979, Tilly 1990). Italian
Renaissance cities only resisted after their engineers discovered how to build wide earth-based walls
that could absorb the impact of cannonballs. Such a process of power concentration was only
reversed by the industrial production of light, one-man, cheap guns and the corresponding creation
of standing armies. 32
4. DISTRIBUTIONAL CONSEQUENCES OF POLITICAL SETTINGS
In the model the final distribution of income is a function of the following factors: the nature
of the technological shock (which could in itself lead to more or less variance in income), the final
regime in place, the extraction rate and the size of the ruling class.
Technological Shock and Population Structure
To examine the effects of different political institutions on the distribution of income, let us
first consider the impact of any technological shock on population. Following the literature on preindustrial economies, assume that net population growth (ΔL) tracks the rate of technological change
32
I am not suggesting that the discovery of standing armies mechanically triggered the process of
political liberalization that has taken place in the last two hundred years. All absolutist states blocked the
introduction of national armies for as long as it was feasible because they contributed to undermine the
position of monarchs and aristocracies. The French revolution broke down an implicit oligopolistic
agreement among absolutist kings to block a new technology of war. In fact, after the defeat of Napoleon,
the Austrian Prime Minister Metternich insisted on an explicit pact to abolish conscription at the
Congress of Vienna. However, once the the battle of Valmy (1793) and all the Napoleonic campaigns had
demonstrated the superiority of universal conscription, most states ended up adopting some kind of
standing army over time: Prussia immediately after the defeat at the hands of Napoleon, Russia after the
Crimean war and Austria after its defeat at the hands of Germany. For recent analysis suggesting that
modern war contributed to extension of political rights and/or to higher levels of taxation, see Levi
(1997), Peacock and Wiseman (1961) ans Scheve and Stasavage (2010).
35
(ΔA). That assumption implies that population adjusts so that output per person equals some
subsistence income ŷ = Y/L. This fits two key features of pre-industrial societies. First, the level of
material welfare in pre-industrial societies is not very different, at least in terms of vital statistics:
food consumption per capita, life expectancies and health profiles have been found to be similar
across foraging and agricultural societies (Clark 2007: 40-70, 91-111). Second, population densities
are much higher in technologically ‘advanced’ (agrarian) societies than in hunting-gathering
territories. In the latter, population densities fluctuate, mostly depending on climate and land
conditions, between 2 (in a few cases) to less than 0.5 persons per square kilometer (Kelly 1995). By
contrast, recent archaeological studies suggest a density of about 90 persons per square kilometer in
the first Neolithic villages in the Levant about 8,000 to 9,000 years ago (Kuijt 2000).
To calculate the population growth rate (and hence the size of the population) given the level
of technology, take the previous function of ŷ, substitute the production function introduced in
Section 1 for Y and solve for L:
1
L = ( )1/ α A
yˆ
1−α
α
(12)
T
Since T and ŷ are constant, the growth rate of L is (1-α)/α times the growth rate of A.
Given (12) and assuming that the share of the land factor in total output (with no other
output than the one from agricultural activities) was about 2/5 (α=0.4) (Clark 2007: 138), Figure 3.A
displays the evolution of the population (in relative terms) in both foraging and agrarian
communities as the technology changes for the latter one. As soon as the technical know-how
doubles, the agricultural population becomes two and half times larger than the foraging population.
For a technology ten times more advanced, the agricultural population becomes over thirty times
larger than the hunting one (for the same unit of land).
[Figure 3 here]
The Consequences of Regime Type
36
Before the state is established (and institutionalized peace is in place), each individual
receives an income yi and there is no inequality beyond the (relatively bounded) one determined by
the productivity Ai of each individual. In a monarchical system, instead, the ruler siphons off a share
ε of every individual to himself (and his servants and allies) and hence gets (ε-γ)λyiN with N denoting
the number of subjects while each subject keeps (1-ε)yi in each period. (For any minimal number of
subjects, this process of redistribution always increases inequality.) By contrast, in a republican or
self-governing polity every citizen keeps (1-1/θD)yi and inequality does not vary with respect to the
pre-shock world. (For the sake of simplicity I will assume λ=1 throughout this section).
[Figure 4 here]
Productivity Shock and Income Distribution. Employing the parameters of the model,
Figures 4 and 5 simulate the distribution of income under different economic and political
conditions. Figure 4.A displays the evolution of material conditions for i and j individuals as the i
individuals benefit from a growing productivity shock (represented in the horizontal axis). Figure
4.A assumes that, once the shock makes the spontaneous peace equilibrium across communities
unfeasible, the j-individuals organize and have a better military technology than producers, impose a
monarchy and extract some of the producers’ income (at the highest feasible extraction rate). 33 As
the productive shock increases and provided the monarchical regime is in place, the position of the
ruling class improves to the point that for A=10 is eighteen times higher than the producers’ per
capita income. The Gini index goes up to around 0.29 if the productive individuals double their
output and the ruling class in a monarchical system imposes the corresponding highest feasible
extraction rate, that is, 48 per cent, to about 0.34 percent.
Size of the Ruling Group. As noted before, holding the feasible rate of extraction constant,
the distribution becomes the more unequal, the smaller the number of rulers relative to the
population of the country. Figure 4.B examines the effect of reducing the size of the ruling group
while holding the extraction rate fixed (at 0.6). The Gini index goes from less than 0.1 to around 0.6.
33
The parameters assumed are δ=0.7, θD=0.6, λ=0.5.
37
Variable Extraction Rate. Figure 4.C explores the impact of a changing extraction rate on
the final distribution of income. For the same proportion of rulers, the Gini index increases from 0.17
to 0.44 as the extraction rate climbs up to 70 percent.
[Figure 5 here]
Monarchies versus Republics. Figure 5 compares the income distribution under a
monarchical and republican regime. To make the analysis richer, the baseline distribution of income
is different than in Figures 4.A to 4.C. Instead of two types, the shock differentiates the population
into ten segments or deciles. 34 The tenth decile does not experience any shock (y10 = 1) – it
corresponds to the type-j individuals of Figure 4. The other deciles experience an increase in
productivity – but the extent of the raise varies across them. However, the increase is bounded so
that they have an incentive to cooperate among them. (The lowest increase, the one experienced by
the first decile, is big enough to make it impossible for those individuals that do not get any increase
(those in the 10th decile) to maintain a cooperative relationship with the rest of the population.) In
Figure 5 the post-shock income ranges from 2 for the first decile to 3.58 for the ninth decile (the
tenth decile keeps receiving 1). A monarchical system leads to a strong redistribution of income. The
tenth decile becomes the richest one: it has a per capita income that is about nine times larger than
the poorest decile’s and it controls almost 39 percent of all the wealth. The Gini index more than
doubles to 0.35 under a monarchy. By contrast, a republican system reduces the initial distribution
slightly – as a result of the tax burden to defend the human settlement. Under an “imperial republic”
(where the tenth decile is expropriated by the majority), inequality does not increase by much: even
with the highest extraction rate, the Gini index inches up from 0.14 to 0.19.
34
This differentiation is done by assumption. The assumption can be justified as follows: consider the
case in which different segments experience different technology shocks and choose the same population
growth rate, unlinked to the technological growth rate (in contrast to expression (12) where both were
functionally related).
38
Although I do not consider the following point in the simulation, the distribution of income
may be also shaped by the way in which rulers extract their resources or, in other words, what kinds
of alliances they form with different strata of producers. The distribution of income becomes highly
skewed when the rulers ally with the richest fraction of the population (this would be equal to
imposing a lower extraction rate ε on them than on other groups) or where the ruling elite simply
replace the existing segment of wealthy individuals. By contrast, the ruling elite may favor a more
equalized structure of income within the producers’ population. These different outcomes, resulting
from different institutional (and taxation) choices, are particularly apparent in processes of
repopulation and colonization. After the Christian kingdoms of Northern Spain took over most of the
Southern half of the Iberian Peninsula in the 13th century, they differed markedly in their strategies
of land redistribution. Castile and Portugal favored the formation of large landholdings. Catalans
settled in Valencia through small farms (Vicens Vives 1957). Similarly, the conquest of America
followed very divergent paths: farming communities settled in the Northeastern seaboard and in
Quebec; the Caribbean basin and Central and South America were dominated by landowners. In all
those cases the distribution of land partly responded to economic considerations, such as the type of
natural endowments and the supply of labor (Engerman and Sokoloff 2002). But it was strongly
affected by the way in which the ruling elites decided to structure the distribution of assets. That was
in turn related to the prevailing political institutions and societal conditions back in the conquering
countries: the Castilian monarch relied upon the high nobility and military orders to conquer
Andalusia in the thirteenth century.
Some Empirics
The simulated extraction rates and Gini indexes fall in line with the available historical
evidence. According to data gathered by Milanovic et al. (2007) and reproduced in Table 3, in
almost all pre-industrial regimes the Gini index fluctuated around 0.40 and in most cases the top 10
39
percent of the distribution controlled more than two fifths of total income. Bourguignon and
Morrisson (2002) offer similar data across the world in 1820, at the dawn of the industrial
revolution.
[Table 3 here]
Given the lack of reliable data on income distribution before the 19th century, one possible
strategy to understand the income consequences of regimes is to employ height as a proxy for access
to resources, health status and general welfare. As discussed in Steckel (1995), height and individual
income seem to be strongly correlated and, as a result, the distribution of heights should provide us
with clues about how that society distributed its resources, at least in human communities living
under conditions of scarcity. 35 In fact, we know that insufficient nutrition was widespread and that
the access to food was biased across social strata in pre-industrial economies: for example, in
England in 1790 whereas the top decile consumed 4,329 kg cal per day; the bottom decile consumed
1,545 kg cal per day (Fogel 1994).
Table 4 summarizes a more extensive discussion of data reported in Boix and Rosenbluth
(2006) on the level of variance in height across times and within different societies. Inequality is low
within tribal, pre-agrarian groups. With the transition to a fully agricultural society with complex
political institutions, heights vary strongly with the type of political regime. In ancient kingdoms and
absolute monarchies, there is considerable differentiation among individuals: the height gap between
nobles and peasants goes from 7 to 9 cm. Using fitted models between log income (in constant
dollars of 1985) and height (Steckel 1995), this difference translates into an income ratio of 5 or 6 to
1 between both groups. 36 By contrast, more democratic settings (although still predominantly
agrarian such as Ohio in middle of the 19th century) show a much more compressed height structure.
35
For a critique, mostly directed at crude cross-country or cross-ethnic group comparisons, see Eaton
(2007).
36
This ratio matches the ratio of the 95th centile/50th centile in the data Bourguignon and Morrisson
(2002) offer for several (46) world areas in 1820.
40
[Table 4 here]
5. CONCLUSIONS
Broadly speaking, the distribution of income in human societies has been characterized by
the following pattern. First, primitive (stateless, pre-agrarian) societies displayed (and still display
wherever they exist) relatively equal distributions of income and certainly very low level of
intergenerational transmissions of wealth. Second, the agricultural revolution came hand in hand
with the emergence of marked inequalities of income (across individuals and over generations) and
the formation of the state. Third, the type of political institutions and the level of inequality has
varied considerably across historical communities since the invention of agriculture.
This paper develops a theoretical model to explain the transition away from relatively equal
pre-agrarian societies. After the end of the last glacial period, a process of learning and
experimentation resulted in territorially differentiated technological shocks that generated inequality
(within but mostly across human bands). That inequality made spontaneous cooperation unfeasible.
That opened the way to both political institutions and further shifts in income distribution. In
response to the productivity growth, the more productive individuals responded by accepting (even if
reluctantly) the protection of their potential looters in exchange for some systematic payments.
Alternatively, they could choose to devote part of their time and income to defend themselves
against those bandits. Both outcomes (‘monarchical’ and ‘republican’), strongly driven by the
evolution of military technologies, had distinctive effects on the distribution of resources – with
monarchical regimes generating and sustaining much higher levels of inequality than republican
systems. The theoretical results match the existing descriptive work as well as broader empirical
work compiled in Boix and Rosenbluth (2006).
Understanding the sources of states institutions and of income inequality is in fact important
to explain economic development and the contemporary process of democratization. The emergence
of the state had a considerable stabilizing effect on the distribution of income over time. As
41
discussed in Boix (2010), authoritarianism, economic stagnation and inequality came together in an
overwhelming majority of Ancien Régime polities -- income inequality only started to trend
downward in a systematic fashion after the industrial revolution. That was a direct outcome of the
incentive structure of their ruling elites. The latter’s final income depended, directly, on the returns
to their assets and, indirectly, on the extraction rate embodied on the existing political institutions,
themselves endogenous to the prevailing income distribution. Hence, those governing had a direct
interest in protecting the status quo and in blocking any process of economic and political
liberalization.
42
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47
TABLE 1. ESTIMATING THE CAUSES OF THE AGRICULTURAL REVOLUTION
Model 1
Model 2
Model 3
Model 4
Model 5
Dependent Variable
Animals
Plants
Animals
And Plants
Years to
Agriculture
Years
to Agriculture
Constant
-3.023***
(0.683)
-5.214**
(2.506)
-24.474***
(7.273)
11,252.226***
(455.150)
11,140.786***
(461.598)
Climate
0.492***
(0.181)
1.540**
(0.665)
5.148***
(1.9292)
-830.410***
(120.751)
-959.365***
(125.037)
Latitude
0.008
(0.005)
0.0781***
(0.020)
0.169***
(0.058)
8.056**
(3.614)
-27.554***
(7.992)
(Latitude)2
-0.017
(0.011)
0.0080
(0.042)
-0.061
(0.120)
73.574***
(7.531)
131.756***
(13.869)
EW Axis / NS Axis
3.778***
(0.350)
8.690***
(1.283)
33.461***
(3.723)
-1,479.413***
(233.010)
-1,169.922***
(243.907)
Island
-3.329***
(0.502)
-9.946***
(1.842)
-33.035***
(5.345)
2,299.943***
(334.573)
1,688.177***
(360.257)
Observations
R-squared
234
0.5580
234
0.4693
234
0.5303
234
0.5477
203
0.5485
Standard errors in parentheses. *** p<0.01, ** p<0.05, * p<0.1
48
TABLE 2. ESTIMATING THE EMERGENCE OF STATES
Dependent Variable
Emergence of State -----------------------------------------------(Original & Derivative)
Model 1
Model 2
Model 3
Constant
2,540.131***
(211.439)
2,474.894***
(218.471)
1,263.651*** 1,255.726***
(43.309)
(51.029)
1,266.825***
(173.048)
Climate
-260.769***
(54.822)
-311.078***
(57.753)
Latitude
4.693***
(1.682)
-9.436**
(3.758)
(Latitude)2
22.853***
(3.443)
45.736***
(6.455)
EW Axis / NS Axis
-928.002***
(112.164)
-792.815***
(119.894)
Island
706.341***
(155.587)
448.982***
(171.475)
0.327***
(0.016)
0.324***
(0.019)
0.446***
(0.046)
Year of Transition
To Agriculture
Model 4
Emergence of State
(Only Original)
Model 5
Observations
229
198
229
198
46
R2
0.449
0.454
0.638
0.607
0.684
Standard errors in parentheses
*** p<0.01, ** p<0.05, * p<0.1
49
TABLE 3. SOME INEQUALITY STATISTICS
Roman Empire ca. 14 AD
Byzantium 1000
(a)
England/Wales 1688 (a)
Moghul India 1750 (a)
Mexico 1790 (a)
Naples 1811 (a)
Brazil 1872 (a)
(a)
Gini
Top 10 percent
0.36
0.41
0.45
0.39
0.64
0.28
0.39
0.44
0.46
0.38
0.35
0.61
0.35
France 1780 (b)
0.56
(a) Milanovic et al. (2007).
(b) Morrisson 2000
50
TABLE 4. POLITICAL SETTINGS AND DIFFERENCES IN MALE HEIGHTS
INSTITUTIONS, PLACE
MEAN
(IN CM.)
DIFFERENCE
(IN CM.)
165.8
161.1
4.7
Pre-State Societies
Zuni Pueblos (before 1680 AD.)
Height at 90th centile
Height at 50th centile
Monarchical/Authoritarian
Ancient Egypt (New Kingdom)
Royal family
Commoners
174
166
8.0
Mycenae
Royal
Commoners
172.5
166.1
6.4
170.6
165.2
162.9
7.7
173.3
174.0
174.7
175.5
2.2
Poland – 17th cent.
Noble
Rural Non-Jewish
Jewish
Democratic
Ohio Recruits, Mid 19th Century
Laborers
Skilled Workers
Farmer
Professional
Source: Boix and Rosenbluth (2006).
51
AULAUL
AULJPN
HAI
CUB
MAGMAG
NMARIPHI
PNG
LIB
UAE
SAU
RUSRUS
USA
CAN
CAN
AULAUL ARG
CANALG
RUS
ICE
USA
USA
CANCHLRUSCAN
ARGARG CHL
NEW
NEW
SURI
BOT MZM
NAM
USA
SAF
CAN
MAW
ZAM
ANG
TAZ
ZAI
FIN
VEN
CENSEN
CAO
NIG
CHNRUS
CHN
MON
CHN
KZK
INS
SOMNIR
CHA
INS
MLI
COL
BRABRABRA
URU
ARG
ALG
IVO
MAA
BOL
CHL HON
PARTHI ALG
USA
MOR
BRU PERPERMEX
INS
ETI
USAUSA
JPNSUD
IND
CHNROK LIT
MYA
IND
RUS
SWD
NOR
IND
DEN
UK
NTH
MEX
CHN
SUD
CHN
EGY
RUS
SPN
YEM
RUM FRN
CRO
IND
RUS
AFG
CHN GRC
IRN
IRQ
SYR
0
Years to the Introduction of Agriculture
5000
10000
15000
Figure 1. Transition to Agriculture and Biogeographical Conditions
Figure 2. Transition to Agriculture and Birth of State Institutions
SYR
IRQ
PNG
INSCEN
NAM
ALG
MZM
USA
CAN
SUDUSA
LIB
ALG
CAN
NEWARG
NEWAUL
AUL
AUL
AUL
BOT
CHL
USA
BRA
RUS
USAUSA
USA
SAF
USA
CAN
CAN
RUSUSA
ZAI ZAM
MAGSURI
RUS
URU
MEXIVO
BRACAO
PAR
COL
VEN
HAI ARG
DOM
CUB
BAH
ARG
MAW
ZAI ANG
JPN
ETI CHL
KZK
RUS
MON
TAZ
SOM
NIG
SWD
FIN
NIR
PHI
ICE
RUS
CHASEN
NOR
MLI
YEM
CHN
SAU
PERMAA
BOL
MEX
JPN
HON
RUS
MYA
UK
NTH DEN
INS
INS
INSCHN
CHN
CHN
THI
IND
SPN
CHN
AFGRUS
RUS
SUD
ALG
IRN
UAE
FRN
MOR
CRO
CHN
ROK
IND
IND
RUM
CHN
CHN
GRC
IND
PAK
EGY
-8000
Year of Emergence of State Institutions
-6000
-4000
-2000
0
2000
.8
1
.4
.6
.2
Biogeographical Conditions (Climate, Latitude, Ratio Axis, Continental Land)
-2000
0
2000
-8000
-6000
-4000
Aprroximate transition year to agriculture. Based on Bellwood and on Parker
52
Figure 3.Technological Change and Population Growth
35
30
Number of individuals
25
20
15
10
5
0
1
2
3
4
5
6
7
8
9
10
Level of Technology (Value of A)
Population of Producers
Population of Bandits
Figure 4.A. Monarchical Rule and Productivity Shock
0.9
20
0.8
18
16
0.7
12
0.5
10
0.4
8
0.3
6
0.2
4
0.1
2
0
0
1
2
3
4
5
6
7
8
Level of Technology (Value of A)
Percentage of Income Controlled by Monarchical Class
Gini Index
Per Capita Income of Monarchical Class
Per Capita Income of Producer
53
9
10
Per Capita Income
Proportion / Gini Index
14
0.6
Figure 4.B. Monarchical Regime and Change in Size of Ruling Group
0.9
20
0.8
18
16
0.7
12
0.5
10
0.4
8
Per Capita Income
Proportion / Gini Index
14
0.6
0.3
6
0.2
4
0.1
2
0
0
0
0.1
0.2
0.3
0.4
0.5
Proportion of Monarchical Class
Percentage of Income Controlled by Monarchical Class
Gini Index
Per Capita Income of Ruling Group
Per Capita Income of Producers
Figure 4.C. Monarchical Rule and Varying Extraction Rate
0.9
20
0.8
18
16
0.7
12
0.5
10
0.4
8
0.3
6
0.2
4
0.1
2
0
0.25
0
0.30
0.35
0.40
0.45
0.50
0.55
0.60
Extraction Rate
Percentage of Income Controlled by Monarchical Class
Gini Index
Per Capita Income of Ruling Group
Per Capita Income of Producers
54
0.65
0.70
Per Capita Income
Proportion / Gini Index
14
0.6
Figure 5. Income Distribution Under Monarchical and Republican Regimes
10
9
Per Capita Income for Each Decile
8
7
6
5
4
3
2
1
0
1
2
3
4
5
6
7
8
9
10
Decile
Income after shock without state
Income under Monarchy
Income under Republic
55
Income under Imperial Republic