Bargaining over power: when do shifts in power lead to war?

Students of international relations have long argued that large and rapid shifts in relative power can lead to war. But then why does the rising state not alleviate the concerns of the declining one by reducing its expected future power, so that a commitment problem never emerges? For example, states often limit their ability to launch preemptive attacks by creating demilitarized zones, or they abandon armament programs to avoid preventive wars. In a model of complete information, I show that shifts in power never lead to war when countries can negotiate over the determinants of their power. If war occurs, then, it must be that negotiations over power are impossible or too costly. I then show how third parties, domestic politics, and problems of fungibility can increase the costs of such negotiations, and hence lead to war, even under complete informatio

The Rationality of Prejudices

We model an -player repeated prisoner's dilemma in which players are given traits (e.g., height, age, wealth) which, we assume, affect their behavior. The relationship between traits and behavior is unknown to other players. We then analyze the performance of “prejudiced” strategies—strategies that draw inferences based on the observation of some or all of these traits, and extrapolate the inferred behavior to other carriers of these traits. Such prejudiced strategies have the advantage of learning rapidly, and hence of being well adapted to rapidly changing conditions that might result, for example, from high migration or birth rates. We find that they perform remarkably well, and even systematically outperform both Tit-For-Tat and ALLD when the population changes rapidly

How Wealth Accumulation Can Promote Cooperation

Explaining the emergence and stability of cooperation has been a central challenge in biology, economics and sociology. Unfortunately, the mechanisms known to promote it either require elaborate strategies or hold only under restrictive conditions. Here, we report the emergence, survival, and frequent domination of cooperation in a world characterized by selfishness and a strong temptation to defect, when individuals can accumulate wealth. In particular, we study games with local adaptation such as the prisoner's dilemma, to which we add heterogeneity in payoffs. In our model, agents accumulate wealth and invest some of it in their interactions. The larger the investment, the more can potentially be gained or lost, so that present gains affect future payoffs. We find that cooperation survives for a far wider range of parameters than without wealth accumulation and, even more strikingly, that it often dominates defection. This is in stark contrast to the traditional evolutionary prisoner's dilemma in particular, in which cooperation rarely survives and almost never thrives. With the inequality we introduce, on the contrary, cooperators do better than defectors, even without any strategic behavior or exogenously imposed strategies. These results have important consequences for our understanding of the type of social and economic arrangements that are optimal and efficient

Saving Human Lives: What Complexity Science and Information Systems can Contribute

We discuss models and data of crowd disasters, crime, terrorism, war and disease spreading to show that conventional recipes, such as deterrence strategies, are often not effective and sufficient to contain them. Many common approaches do not provide a good picture of the actual system behavior, because they neglect feedback loops, instabilities and cascade effects. The complex and often counter-intuitive behavior of social systems and their macro-level collective dynamics can be better understood by means of complexity science. We highlight that a suitable system design and management can help to stop undesirable cascade effects and to enable favorable kinds of self-organization in the system. In such a way, complexity science can help to save human lives.Comment: 67 pages, 25 figures; accepted for publication in Journal of Statistical Physics [for related work see http://www.futurict.eu/

Bargaining over power: When do shifts in power lead to war?

ISSN:1752-9719ISSN:1752-972

Negotiating Power.

Power is the fundamental determinant of international outcomes. It determines who gets what and at what cost, who is most likely to win a war, and what decisions are adopted in international negotiations. As such, it is often an object of strategic behavior itself. For example, states negotiate over their armament; they fight to increase their future strength; and they sometimes pretend to be stronger than they actually are. This book is about power, its value, and when and why its pursuit leads to war. Using bargaining models in which power—the ability to hurt or to offer rewards—is endogenous, I analyze states’ strategies toward power. When do they fight to increase it? When, on the contrary, do they tame it down to alleviate the fears of their neighbors and avoid war? How do they misrepresent their strength? And how do they allocate their scarce means of coercion at different fronts?Ph.D.Political ScienceUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/63832/1/chadefau_1.pd

Replication Data for: Nowhere to Go: Why do Some Civil Wars Generate More Refugees than Others?

Civil wars greatly vary in the number of refugees they generate, ranging from zero to over six millions in a given conflict. Work on this variation has largely focused on ‘push’ factors—deleterious attributes of the home country that lead to refugee flows, such as violence and repression. Yet, few have studied the importance of ‘pull’ factors—attractive features of the potential host countries. Here we show in particular the importance of the expected quality of life in possible destinations. Using data on civil wars from 1951 to 2008, we find that the proximity of democratic and wealthy potential hosts accounts for much of the variation in the number of refugees. Out-of-sample validation methods show that these ‘pull’ factors account for nearly as much predictive power as all the main variables previously identified in the literature combined

Asymptotic <i>proportion</i> of cooperators without and with wealth accumulation.

<p>The contour plot shows the average final proportion of cooperators in the world, as a function of the payoff parameters (horizontal axis) and (vertical axis). (A) In a world in which payoffs are homogenous across agents, the proportion of cooperators is low for any . (B) In an unequal environment, in which the rich can become richer, cooperation is stable for a much larger range of payoff parameters. The top-left quadrant corresponds to the harmony game (HG); the bottom-left ( and ) to the stag-hunt (or ‘assurance’) game (SH); the upper-right quadrant (, ) to the snowdrift (or ‘chicken’) game (SD); and the lower-right quadrant ( and ) corresponds to the prisoner's dilemma (PD) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0013471#pone.0013471-Roca1" target="_blank">[33]</a>.</p