The supply side determinants of territory
| Author | Jordan Adamson,Erik O Kimbrough |
| DOI | http://doi.org/10.1177/00223433221075006 |
| Published date | 01 March 2023 |
| Date | 01 March 2023 |
| Subject Matter | Regular Articles |
The supply side determinants of territory
Jordan Adamson
Institute for Empirical Research in Economics, Leipzig University
Erik O Kimbrough
Smith Institute for Political Economy and Philosophy, Chapman University
Abstract
This article introduces a simple application of contest theory that neatly captures how Boulding’s ‘loss of strength
gradient’ determines the geographic extent of territory. We focus on the ‘supply side’ of territorial conflict, showing
how the costs of initiating and escalating conflict over spatially dispersed resources shape the nature and scope of
territory. We show that economies of scale in the production of violence and varying costs of projecting power at a
distance combine to affect the intensive and extensive margins of conflict, and ultimately the geographic distribution
of territory. Comparative statics analysis shows how the distribution of conflict and territory change as costs change,
helping shed light on, for example, why new transportation technologies have historically led to a redrawing of
territorial boundaries. We test and probe the boundaries of this model in two experiments varying the marginal costs
of conflict over space and the fixed costs of entry. Increases in both costs interact to increase the probability of
exclusive territories. The first experiment directly tests the theory in a static, one-shot setting that strictly matches the
information conditions studied in the theory. The second experiment examines conflict behavior under conditions
analogous to those in conflicts outside the lab: where no contestant knows the probability of winning, let alone the
function determining that probability, and parties interact repeatedly. Median behavior closely tracks equilibrium
predictions in all treatments.
Keywords
conflict, experiments, territory
Introduction
We explore how the costs of conflict influence the size
and shape of territory. We develop a simple model of a
multibattle contest with heterogeneous costs to capture
the classic ‘loss-of-strength gradient’ introduced by
Boulding (1962), in which the ability to project power
decreases with distance. When combined with econo-
mies of scale in the production of violence, these factors
predict the intensive and extensive margins of conflict
and ultimately the geographic distribution of territory.
Comparative statics analysis shows how the distribution
of conflict and territory change as costs change, helping
shed light on, for example, why new transportation tech-
nologies (such as the chariot) have historically led to a
redrawing of territorial boundaries.
We conduct two sets of experiments to assess the
robustness of the basic implications of the model. The
first set of experiments directly tests the equilibrium and
comparative static predictions of the theory in a static,
one-shot setting with a commonly known contest suc-
cess function determining the outcome of conflict. The
second set of experiments probes the boundaries of the
theory by allowing us to study conflict behavior under
conditions analogous to those in conflicts outside the
lab: where no contestant knows the probability of win-
ning, let alone the function determining that probability,
and parties interact repeatedly. Despite the major
Corresponding author:
ekimbrou@chapman.edu
Journal of Peace Research
2023, Vol. 60(2) 209–225
ªThe Author(s) 2022
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DOI: 10.1177/00223433221075006
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changes to the choice setting, evidence from both sets of
experiments is strikingly consistent with the equilibrium
and comparative statics of the theoretical model. Theory
and evidence both suggest that, all else equal, the cost
structure of conflict is an important determinant of the
scope of territory. We conclude by discussing additional
insights generated by our setup and possible extensions.
Failure to account for the spatial element in conflict
has been identified as a major gap in the literature by
political scientists (Hansel in Vasquez, 2012: 22), econ-
omists (Kimbrough, Laughren & Sheremeta, 2017), and
biologists (Rusch & Gavrilets, 2017).
1
To fill this gap,
we start from the rare and original economic analysis by
Boulding (1962) of the relationship between territory
and the projection of power at a distance. In Boulding’s
theory, contestants each have a ‘base’ located at some
point in space (e.g. at points along a line, see Figure 1).
The ‘power’ of an agent is represented graphically by the
height of the bar at its base. Agents project power from
their base, and their capacity to do so diminishes with
distance. Boulding’s model defines territorial boundaries
as the point in space where the power of contestant A is
equal to the power of contestant B, that is, point E in the
figure. To the left of E, we have A’s territory, and to the
right of E, we have B’s territory.
Boulding’s simple spatial framework captures compel-
ling intuitions: all else equal, stronger agents will have
larger territories; territories further from an agent’s power
base are more likely to be contested by others; changes in
the cost of projecting power change the distribution of
territory; and so on. However, Boulding did not provide
an explicit model of the incentives that generate these
patterns. To do so, we integrate the literature on asym-
metric conflict and conflict entry (Gradstein, 1995; Ritz,
2008; Morgan, Orzen & Sefton, 2012; Dari-Mattiacci
et al., 2015) into a spatial environment.
2
Within a sim-
ple model of multibattle contests, we show how variation
in different costs affects both the intensive and extensive
margins of conflict across space, with territories emerging
as a result.
Two agents engage in conflict via Tullock contests
for resources located at points in space. We introduce
spatial variation in marginal conflict costs via ‘the great
principle of the further the weaker’ (Boulding, 1962),
and we show how this interacts with economies of scale
to cause cost-disadvantaged contestants to exit distant
locations. Changes in fixed costs of entry and changes
in marginal costs of projecting power at a distance can
thus alter the incentives for entry, and studying the
interaction of these different costs provides a parsimo-
nious framework for understanding how supply-side
factors (i.e. the costs of initiating and engaging in con-
flict over space) influence the distribution of conflict
and territory (as emphasized by e.g. Bean, 1973; Witt-
man, 1991; Latzko, 1993).
3
We use this model to gen-
erate point predictions and comparative statics which
help explain several historical observations and which
we directly test in the lab.
Most definitions of the state encompass some notion
of a territorial monopoly of violence (Weber, 1965; Bar-
zel, 2002; Abramson, 2017). Our model highlights the
fact that territory is not exogenous (Agnew, 1994), and
monopolies are outcomes that depend on the entry
Figure 1. Boulding’s model of territory
1
For instance, though the famous hawk–dove game was designed
(Maynard-Smith & Price, 1973) and advanced (Johnson & Toft,
2014) as a model of territory, it is not spatial. Rusch & Gavrilets
(2017), in their review of biological contests, argues that although
territory is ‘the resource most likely to be contested, it has rarely been
taken into account explicitly’. There are only a few related models on
this topic over decades of research (Tullock, 1983; Anderson &
McChesney, 1994; Baker, 2003; Carter, 2010; Spolaore, 2016;
Dow, Mitchell & Reed, 2017; Acharya & Lee, 2018). Acharya &
Lee’s (2018) is the most closely related article to our own, but they
model territory as a collusive equilibrium to a repeated game between
extractive rulers, explicitly taking a demand-side approach in which
rulers compete to provide governance services to citizens at the lowest
price. Our model builds on the industrial organization literature on
collusive monopoly and market sharing (Ma skin & Tirole, 1988;
Bernheim & Whinston, 1990), but we highlight the non-
cooperative forces that lead to territory when fighting over
resources. In our model , territory can emerge in t he equilibrium
even of the one-shot game, though alternative equilibria could also
be supported in an indefinitely repeated version of our game. Also
related is Krugman (2009), in which fixed costs and transportation
costs interact to determine where firms locate.
2
Also related are Blotto Games (Kovenock & Roberson, 2012). In
our model, resource allocations to a given battlefield are constrained
by costs rather than a budget constraint.
3
Our model also supports the conjecture by Schultz & Goemans
(2019) that limited territorial claims result from discontinuities in the
costs and benefits of acquiring new territories.
210 journal of PEACE RESEARCH 60(2)
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