51766388
On the Spatial Diffusion of Cooperation with Endogenous Matching Institutions
This paper studies the spatial joint evolution of cooperative behavior and a partially assortative matching institution that protects cooperators. We consider cooperation as characterized by a cultural trait transmitted via an endogenous socialization mechanism and we assume that such trait can diffuse randomly in space due to some spatial noise in the socialization mechanism. Using mathematical techniques from reaction-diffusion equations theory, we show that, under some conditions, an initially localized domain of preferences for cooperation can invade the whole population and characterize the asymptotic speed of diffusion. We consider first the case with exogenous assortativeness, and then endogeneize the degree of social segmentation in matching, assuming that it is collectively set at each point of time and space by the local community. We show how relatively low cost segmenting institutions can appear in new places thanks to the spatial random diffusion of cooperation, helping a localized cultural cluster of cooperation to invade the whole population. The endogenous assortative matching institution follows a life cycle process: appearing, growing and then disappearing once a culture of cooperation is sufficiently established in the local population.
2599491
preference evolution under incomplete information and assortative matching
What preferences will prevail in a society of rational individuals when preference evolution is driven by the resulting payos? We show that when individuals' preferences are their private information, a convex combination of selfishness and morality stands out as evolutionarily stable. We call individuals with such preferences homo moralis. At one end of the spectrum is homo oeconomicus ,w ho acts so as to maximize his or her own payo� .A t the opposite end ishomo kantiensis ,w ho does what would be "the right thing to do," in terms of payos, if all others would do likewise. We show that the stable degree of morality - the weight placed on the moral goal - is determined by
3086926
The Algebra of Assortative Encounters and the Evolution of Cooperation
This paper explores the way in which assortative matching can maintain cooperative behavior under evolutionary dynamics. If encounters are random, then in Prisoner's Dilemma games, defectors necessarily get higher payoffs than cooperators and thus will eventually prevail. But if matching is assortative, the cost of cooperating may be repaid by higher probabilities of playing against a cooperating opponent. This paper shows that a simple index of assortativity allows a unifying treatment of the evolutionary dynamics in a wide variety of models of social encounters.
38506099
The Moral Economy of Communities: Structured Populations and the Evolution of Pro-Social Norms
Abstract Why do communities persist despite their inability to exploit the efficiency-enhancing properties of markets and the advantages of universal enforcement of rules provided by states? One reason is the capacity of communities to foster cooperative behavior. Communities align the individual and collective benefits and costs of people's actions. We model three mechanisms by which communities raise the net benefits to individual pro-social behaviors: reputation , retaliation , and segmentation . Unlike most treatments of the evolution of group-beneficial traits our communities promote pro-social behaviors in the absence of group selection. We further show that the restricted mobility associated with communities ( parochialism ) enhances these mechanisms. Communities are thus specifically adapted to settings that make formal property rights systems untenable and preclude the efficient centralized determination of outcomes.
150959130
Altruists, Egoists and Hooligans in a Local Interaction Model
This paper studies a population of agents, each of whom can be either an Altruist or an Egoist. Altruists confer benefits on others at a cost to themselves. Altruism is thus a strictly dominated strategy and cannot survive if agents are rational best-responders. We assume that agents choose their actions by imitating others who earn high payoffs. We also assume that interactions between agents are local, so that each agent affects (and is affected by) only his neighbors. Altruists can survive in such a world if they are grouped together, so that the benefits of altruism are enjoyed primarily by other Altruists, who then earn relatively high payoffs and are imitated.
17723646
Pattern formation, social forces, and diffusion instability in games with success-driven motion
A local agglomeration of cooperators can support the survival or spreading of cooperation, even when cooperation is predicted to die out according to the replicator equation, which is often used in evolutionary game theory to study the spreading and disappearance of strategies. In this paper, it is shown that success-driven motion can trigger such local agglomeration and may, therefore, be used to supplement other mechanisms supporting cooperation, like reputation or punishment. Success-driven motion is formulated here as a function of the game-theoretical payoffs. It can change the outcome and dynamics of spatial games dramatically, in particular as it causes attractive or repulsive interaction forces. These forces act when the spatial distributions of strategies are inhomogeneous. However, even when starting with homogeneous initial conditions, small perturbations can trigger large inhomogeneities by a pattern-formation instability, when certain conditions are fulfilled. Here, these instability conditions are studied for the prisoner’s dilemma and the snowdrift game. Furthermore, it is demonstrated that asymmetrical diffusion can drive social, economic, and biological systems into the unstable regime, if these would be stable without diffusion.
4539848
Spatial invasion of cooperation.
The evolutionary puzzle of cooperation describes situations where cooperators provide a fitness benefit to other individuals at some cost to themselves. Under Darwinian selection, the evolution of cooperation is a conundrum, whereas non-cooperation (or defection) is not. In the absence of supporting mechanisms, cooperators perform poorly and decrease in abundance. Evolutionary game theory provides a powerful mathematical framework to address the problem of cooperation using the prisoner's dilemma. One well-studied possibility to maintain cooperation is to consider structured populations, where each individual interacts only with a limited subset of the population. This enables cooperators to form clusters such that they are more likely to interact with other cooperators instead of being exploited by defectors. Here we present a detailed analysis of how a few cooperators invade and expand in a world of defectors. If the invasion succeeds, the expansion process takes place in two stages: first, cooperators and defectors quickly establish a local equilibrium and then they uniformly expand in space. The second stage provides good estimates for the global equilibrium frequencies of cooperators and defectors. Under hospitable conditions, cooperators typically form a single, ever growing cluster interspersed with specks of defectors, whereas under more hostile conditions, cooperators form isolated, compact clusters that minimize exploitation by defectors. We provide the first quantitative assessment of the way cooperators arrange in space during invasion and find that the macroscopic properties and the emerging spatial patterns reveal information about the characteristics of the underlying microscopic interactions.
128455010
Measuring the Rate of Spread of Early Farming in Europe
A large body of information on early farming in Europe and the Near East has accumulated during the last twenty years of prehistoric research. The economies of most early farming settlements in Europe are characterised by the use of various domesticated species (wheat, barley, sheep, cattle and pig) combined with the exploitation of wild plants and animals. The view generally held sees early farming of the type practised in Europe as having originated in the Near East (Ucko & Dimbleby I969). Thence it appears to have spread first to Greece and the Balkans and subsequently over the rest of Europe (Clark 1965; Neustupny 1968). The extension of early farming across Europe is a subject of interest to a number of disciplines ranging from prehistory and palaeoecology to genetics. In this article, we concentrate on one aspect of the question: the measurement of the rate of spread or diffusion. A previous attempt to measure 'neolithic diffusion rates' was made by Edmonson (I96I). This pioneer study is unsatisfactory in a number of ways: notably in the method of measurement and in the assumption that what was being measured was a rate of cultural or stimulus diffusion.
208525997
The Neolithic transition and the genetics of population in Europe
This book explores the shift from hunting and gathering to agriculture as a way of life and the implications of this neolithic transition for the genetic structure of European populations.Originally published in 1984.The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.
144924100
Neolithic Diffusion Rates
THE DEVELOPMENT of a comprehensive theory of culture appears to be dependent upon more rigorous analysis of the communicative processes which are its basis. I should like here to examine the possibility that certain aspects of these processes are considerably simpler than they appear to be, and primarily reflect general relations between time and the communicative space in which culture is located. Let me begin with a simple model. If we let a circle represent cultural space, then its properties and characteristics generate some useful propositions about cultural communications. Let us assume that the circle is a surface inhabited by a homogeneous field of persons interacting communicatively at some maximal efficiency. In such a field, an invention at the center might be expected to travel in all directions to the circumference at a uniform rate of speed. Other inventions occurring randomly at various points in the circle might also be expected in time to diffuse uniformly throughout he space. The one point in the circle which will have the least mean lag in receiving all of these inventions will, of course, be the center. Let us further assume that some of these inventions tand in an implicative relationship to each other, so that trait c is dependent upon the prior conjunction of traits a and b. It will follow that the earliest possible occurrence of trait c will be, on the average, at the center of the circle. This model would lead us to expect that any single invention of this type would diffuse from its point of origin at a constant rate (measured in sequential persons reached per unit time) throughout cultural space. We should further expect that the probability of at least some types of invention would be a simple inverse function of the distance (in persons) from the center of the circle. In short, communication and invention are predicted by the same variables: time and location in person-space. I believe this model does not fit cultural reality badly. However, it would be difficult o test it on most ranges of cultural data. I shall argue here that, under certain circumstances, the model can adequately be translated into spatial terms, and that the cultural circumstances of the Neolithic period may reasonably be used to test it. From the hypothetical argument, two relevant propositions can be derived:
56260429
Social Capital and Collusion: The Case of Merchant Guilds
Merchant guilds have been portrayed as ‘social networks’ that generated beneficial ‘social capital’ by sustaining shared norms, effectively transmitting information, and successfully undertaking collective action. This social capital, it is claimed, benefited society as a whole by enabling rulers to commit to providing a secure trading environment for alien merchants. But was this really the case? We develop a new model of the emergence, rise and eventual decline of European merchant guilds which explores the collusive relationship between rulers and guilds, and calls into question the prevailing positive view of merchant guilds. We then confront the model’s predictions with the available historical data. The empirical evidence strongly support our model and refutes existing theories. Our findings show that merchant guilds used their social capital for socially harmful as well as beneficial ends.
1906950
The Rise , Persistence and Decline of Merchant Guilds . Re-thinking the Comparative Study of Commercial Institutions in Pre-modern Europe
The importance of merchant guilds for the commercial development of Europe is beyond doubt. However, there is still little agreement as to why they emerged, persisted and ultimately declined between the 11 and 18 centuries. Historical studies have focused on individual cases and idiosyncratic circumstances that restrict severely comparability, while economic approaches based on game or contract theory often impose narrow assumptions on their models which find it hard to deal with two key features of these institutions: in very imperfect markets merchants used more than one institution to solve a given problem while a given institution often addressed more than one problem. In this paper we suggest a new methodological approach that allows us to pursue a comparative analysis without loosing rigour. We assess a new dataset of 185 observations of merchant organisations from four towns 1300-1800 at 50 year intervals. Our model is based on only one assumption: merchants will only delegate control over their dealings if they can expect a positive return from the loss of control. On this basis, we classify our dataset into five ordinal categories of degrees of control delegation. Using maximum likelihood estimation we investigate the probability that merchants, under a given set of market and political circumstances, delegate control. The authors would like to thank Maristella Botticini, Ann Carlos, the late Larry Epstein, Joost Jonker, and participants of the EHES conference Istanbul 2005 as well as the Antwerp workshop on mercantile institutions 2005, the LSE Global Economic History seminar, the Utrecht GEHN conference 2006, the ASSA 2007, the Cliometric Conference 2007, the economic history seminar at the University of British Columbia, the Institutions in Early Modern Europe workshop at CalTech 2008, and the ICS sociology seminar at Utrecht University, for extensive comments and criticism. All the usual disclaimers apply.
201796167
Institutions and the Path to the Modern Economy: Lessons from Medieval Trade (review)
subject of substantial interest and complexity. Uppermost in his treatment are the military functions of railroads and the means by which European powers explored them. Although not unreasonable, this focus may not do justice to the subtler but arguably more profound effects on the international system of railroads as instruments of economic and cultural power. Herrera’s second case study, the development of the atomic bomb, is a much less convincing venue for developing his argument. Much of the study deals with descriptions of the German educational system, the place of physics within that system, and the variety of inouences that led to a decline of physics in Germany at the expense of its rise in the United States, particularly in the period from 1920 to 1940. Although this wellknown story is certainly worth retelling in the context of international politics, it does not well illustrate the more fundamental linkages between technological and international change. The realignment of power that ensued with the introduction of atomic weapons is a wellworn subject, only brieoy summarized by Herrera. The exceptional nature of these weapons makes the case seem less pertinent, rather than more, for supporting his overall case. Finally, the discussion of contemporary information technologies is so cursory and sketchy that the skeptical reader will not and much to support Herrera’s larger case, and the sympathetic reader will probably and little that is original.
154501745
Coordination, Commitment, and Enforcement: The Case of the Merchant Guild
We interpret historical evidence in light of a repeated-game model to conclude that merchant guilds emerged during the late medieval period to allow rulers of trade centers to commit to the security of alien merchants. The merchant guild developed the theoretically required attributes, secured merchants' property rights, and evolved in response to crises to extend the range of its effectiveness, contributing to the expansion of trade during the late medieval period. We elaborate on the relations between our theory and the monopoly theory of merchant guilds and contrast it with repeated-game theories that provide no role for formal organization.
149184918
Sharing Culture: On definitions, values, and emergence
Sharing practices have increased over the last decade as a byproduct of the economic recession and the wider use of online services, creating the hype of ‘Sharing Economy’. However, sharing economy as defined today includes contradictory cases of renting, sharing, commoning, collaboration, solidarity, and typical businesses. This article focuses on cases that outline sharing as an act that facilitates a transition of urban communities towards places that are socially interactive and resourceful. Those practices are defined as ‘Sharing Culture’. Sharing culture relates to social networks that grow informally within a region and have as their goal to co-produce, manage and share resources, time, services, knowledge, information, and support based on solidarity rather than economic profit. Ultimately, sharing culture creates an alternative pathway for citizens to serve daily needs in a more sustainable, resourceful, and socially engaging manner by investing in regional and local assets. Because sharing culture is tightly related to the everyday and the local, the social construct of a region as well as the physical design influence how and where it emerges. Through a theoretical review of sharing practices and empirical data from a short selection of sharing culture cases, this article explores what sharing culture is, how it emerges, and highlights the importance of physical space in the process of diffusion within an area. The goal of this article is twofold: first, to provide a new theoretical framework, that of the sharing culture, which enriches the current debate on sharing and collaborative practices and distances itself from economic transactions of sharing economy, while focusing on human needs and characteristics of solidarity. Second, the article intends to reveal the lack of systematic research on how these practices are influenced by physical space.
15170308
The Economics of Cultural Transmission and the Dynamics of Preferences
This paper studies the population dynamics of preference traits in a model of intergenerational cultural transmission. Parents socialize and transmit their preferences to their offspring, motivated by a form of paternalistic altruism (“imperfect empathy”). In such a setting we study the long run stationary state pattern of preferences in the population, according to various socialization mechanisms and institutions, and identify sufficient conditions for the global stability of an heterogenous stationary distribution of the preference traits. We show that cultural transmission mechanisms have very different implications than evolutionary selection mechanisms with respect to the dynamics of the distribution of the traits in the population, and we study mechanisms which interact evolutionary selection and cultural transmission. Journal of Economic Literature Classification numbers: D10, I20, J13.
1494216
Evolutionary dynamics in set structured populations
Evolutionary dynamics are strongly affected by population structure. The outcome of an evolutionary process in a well-mixed population can be very different from that in a structured population. We introduce a powerful method to study dynamical population structure: evolutionary set theory. The individuals of a population are distributed over sets. Individuals interact with others who are in the same set. Any 2 individuals can have several sets in common. Some sets can be empty, whereas others have many members. Interactions occur in terms of an evolutionary game. The payoff of the game is interpreted as fitness. Both the strategy and the set memberships change under evolutionary updating. Therefore, the population structure itself is a consequence of evolutionary dynamics. We construct a general mathematical approach for studying any evolutionary game in set structured populations. As a particular example, we study the evolution of cooperation and derive precise conditions for cooperators to be selected over defectors.
10206684
Wave Patterns in Spatial Games and the Evolution of Cooperation
Our understanding of the evolution of animal behavior has been greatly enhanced by the use of game theory (Maynard Smith 1982). Classical games assume that a given individual is equally likely to interact with any other member of the population and that the success of any individual depends on the frequency of all other strategies represented in the population. Yet natural environments possess a spatial dimension: individuals have limited mobility and interact locally with their neighbors. Only recently have attempts been made to incorporate this important property into the study of evolutionary games. Different approaches have been followed: numerical simulations of “games on grids” (Nowak and May 1992; Lindgren and Nordahl 1994; see Chapter 8); analytical study of correlation equations for games on lattices (Nakamaru et al. 1997; see Chapter 13); and analytical study of “replicator–diffusion” equations (e.g., Vickers 1989; Vickers et al. 1993; Ferriere and Michod 1995, 1996; see Chapter 22). In this chapter we restrict ourselves to the last of these methodologies and provide an introduction to its mathematical underpinnings and biological applications. Elements of a general theory of replicator–diffusion equations are expounded in detail in articles by Vickers (1989), Hutson and Vickers (1992), Vickers et al. (1993), and Cressman and Vickers (1997). We present an overview of these important results in Section 17.2. Sections 17.3 and 17.4 show how replicator–diffusion models can be used to study spatial versions of the iterated Prisoner’s Dilemma game, a well-known metaphor for evolution toward cooperation between genetically unrelated individuals (Trivers 1971; Axelrod and Hamilton 1981; Maynard Smith 1982; Hofbauer and Sigmund 1998).
53447179
The interplay of cultural intolerance and action-assortativity for the emergence of cooperation and homophily
This paper investigates the emergence of cooperation in a heterogeneous population that is divided into two cultural groups. Agents are randomly matched in pairs to engage in a prisoner dilemma. The matching process is assortative in actions, that is, cooperators are more likely to be matched with cooperators, defectors are more likely to be matched with defectors. Agents exhibit a form of cultural intolerance: when two agents of different cultures are matched, they suffer a cost due to their cultural differences. We find that when cultural intolerance is sufficiently strong, homophily emerges together with perfect correlation between culture and behavior: all agents from one cultural group cooperate, while all agents from the other cultural group defect, and interactions among agents within the same cultural group are more frequent. The relation between cultural intolerance and societal welfare is non-monotonic. In particular, stronger cultural intolerance can increase cooperation when action-assortativity is weak, while it can increase defection when action-assortativity is strong. Moreover, everyone cooperating does not necessarily maximize total welfare unless cultural intolerance can be made sufficiently weak.
55742208
The co-evolution of cooperation and defection under local interaction and endogenous network formation
The Prisoner's Dilemma is a typical structure of interaction in human societies. In spite of a long tradition dealing with the matter from different perspectives, the emergence of cooperation or defection still remains a controversial issue from both an empirical and a theoretical point of view. In this paper we propose a local interaction model with endogenous network formation, in the attempt to provide a reasonable account of emerging behaviors. A population of boundedly rational agents repeatedly chooses to cooperate or defect. Each agent's action affects only her interacting mates, according to a network of relationships. Agents are randomly given the possibility to substitute undesired mates with unknown ones. Full cooperation, full defection and coexistence of both cooperation and defection in homogeneous clusters are possible outcomes of the model. Computer-based simulations are applied to investigate under what circumstances either case is most likely.
40157840
Assortativity evolving from social dilemmas.
Assortative mechanisms can overcome tragedies of the commons that otherwise result in dilemma situations. Assortativity criteria include various forms of kin selection, greenbeard genes, and reciprocal behaviors, usually presuming an exogenously fixed matching mechanism. Here, we endogenize the matching process with the aim of investigating how assortativity itself, jointly with cooperation, is driven by evolution. Our main finding is that full-or-null assortativities turn out to be long-run stable in most cases, independent of the relative speeds of both processes. The exact incentive structure of the underlying social dilemma matters crucially. The resulting social loss is evaluated for general classes of dilemma games, thus quantifying to what extent the tragedy of the commons may be endogenously overcome.
589307
On the Joint Evolution of Culture and Institutions
Explanations of economic growth and prosperity commonly identify a unique causal effect, e.g., institutions, culture, human capital, geography. In this paper we provide instead a theoretical modeling of the interaction between culture and institutions and their effects on economic activity. We characterize conditions on the socio-economic environment such that culture and institutions complement (resp. substitute) each other, giving rise to a multiplier effect which amplifies (resp. dampens) their combined ability to spur economic activity. We show how the joint dynamics of culture and institutions may display interesting non-ergodic behavior, hysteresis, oscillations, and comparative dynamics. Finally, in specific example societies, we study how culture and institutions interact to determine the sustainability of extractive societies as well as the formation of civic capital and of legal systems protecting property rights.