An evolutionary edge of knowing less (or: On the ‘curse’ of global information)

Consider a population of farmers who live around a lake. Each farmer engages in trade with his two adjacent neighbors. The trade is governed by a prisoner’s dilemma ‘rule of engagement.’ A farmer’s payoff is the sum of the payoffs from the two prisoner’s dilemma games played with his two neighbors. When a farmer dies, his son takes over. The son decides whether to cooperate or defect by considering the actions taken and the payoffs received by the most prosperous members of the group comprising his own father and a set of his father’s neighbors. The size of this set, which can vary, is termed the ‘span of information.’ It is shown that a larger span of information can be detrimental to the stable coexistence of cooperation and defection, and that in well-defined circumstances, a large span of information leads to an end of cooperation, whereas a small span does not. Conditions are outlined under which, when individuals’ optimization is based on the assessment of less information, the social outcome is better than when optimization is based on an assessment of, and a corresponding response to, more information.     

Conformism and cooperation in a local interaction model

We analyze a local interaction model where agents play a bilateral prisoner’s dilemma game with their neighbors. Agents learn about behavior through payoff-biased imitation of their interaction neighbors (and possibly some agents beyond this set). We find that the Eshel et al. (Am Econ Rev 88:157–179, 1998) result that polymorphic states are stochastically stable in such a setting is not robust. In particular, whenever agents use information also of some agents beyond their interaction neighbors, the unique stable outcome is one where everyone chooses defection. Introducing a sufficiently strong conformist bias into the imitation process, we find that full cooperation always emerges. Conformism is thus identified as a new mechanism that can stabilize cooperation.

Revisiting strategic versus non-strategic cooperation

We propose a novel experimental method that disentangles strategically- and non-strategically-motivated behavior. We apply it to an indefinitely-repeated prisoner’s dilemma game to observe simultaneously how the same individual behaves in situations with future interaction and in situations with no future interaction, while controlling for expectations. This method allows us to determine the extent to which strategically-cooperating individuals are responsible for the observed pattern of cooperation in experiments with repeated interaction, including the so-called endgame effect. Our results indicate that the most common motive for cooperation in repeated games is strategic.     

Parental education and wages: Evidence from China

This paper investigates the relationship between parents’ education and children’s wage using two nationally representative data sets in China. Controlling for other things, both father’s and mother’s education are positively correlated with children’s wage. Nevertheless, returns to father’s education are lower in more market-oriented segments of the economy, including coastal regions, the non-state sector, and the later period of the reform era (post-1992), while the opposite is true for mother’s education. We argue that this new empirical evidence is consistent with the story that father’s education mainly indicates family connections useful for locating a better-paying first job, while mother’s education primarily captures unmeasured ability.     

Equilibrium existence and approximation of regular discontinuous games

Many conditions have been introduced to ensure equilibrium existence in games with discontinuous payoff functions. This paper introduces a new condition, called regularity, that is simple and easy to verify. Regularity requires that if there is a sequence of strategies converging to s* such that the players’ payoffs along the sequence converge to the best-reply payoffs at s*, then s* is an equilibrium. We show that regularity is implied both by Reny’s better-reply security and Simon and Zame’s endogenous sharing rule approach. This allows us to explore a link between these two distinct methods. Although regularity implies that the limits of e{\epsilon}-equilibria are equilibria, it is in general too weak for implying equilibrium existence. However, we are able to identify extra conditions that, together with regularity, are sufficient for equilibrium existence. In particular, we show how regularity allows the technique of approximating games both by payoff functions and space of strategies.     

On the evolutionary edge of migration as an assortative mating device

In a haystack-type representation of a heterogeneous population that is evolving according to a payoff structure of a prisoner’s dilemma game, migration is modeled as a process of ‘swapping’ individuals between heterogeneous groups of constant size after a random allocation fills the haystacks, but prior to mating. Migration is characterized by two parameters: an exogenous participation-in-migration cost (of search, coordination, movement, and arrangement-making) which measures the migration effort, and an exogenous technology—of coordinating and facilitating movement between populated haystacks and the colonization of currently unpopulated haystacks—which measures the migration intensity. Starting from an initially heterogeneous population that consists of both cooperators and defectors, a scenario is postulated under which ‘programmed’ migration can act as a mechanism that brings about a long-run survival of cooperation.

SOCIAL NORMS,LOCAL INTERACTION,AND NEIGHBORHOOD PLANNING*

This article examines optimal social linkage when each individual's repeated interaction with each of his neighbors creates spillovers. Each individual's discount factor is randomly determined. A planner chooses a local interaction network or neighborhood design before the discount factors are realized. Each individual then plays a repeated Prisoner's Dilemma game with his neighbors. A local trigger strategy equilibrium (LTSE) describes an equilibrium in which each individual conditions his cooperation on the cooperation of at least one “acceptable” group of neighbors. Our main results demonstrate a basic trade‐off in the design problem between suboptimal punishment and social conflict. Potentially suboptimal punishment arises in designs with local interactions since in this case monitoring is imperfect. Owing to the heterogeneity of discount factors, however, greater social conflict may arise in more connected networks. When individuals' discount factors are known to the planner, the optimal design exhibits a cooperative “core” and an uncooperative “fringe.”“Uncooperative” (impatient) types are connected to cooperative ones who tolerate their free riding so that social conflict is kept to a minimum. By contrast, when the planner knows only the ex ante distribution over individual discount factors, then in some cases the optimal design partitions individuals into maximally connected cliques (e.g., cul‐de‐sacs), whereas in other cases incomplete graphs with small overlap (e.g., grids) are possible.     

Adam Smith and Immanuel Kant: On Markets,Duties, and Moral Sentiments

This note points out a neglected parallel between the philosophies of Adam Smith and Immanuel Kant related to their views on self-interest, morality, and society. First, I explain the distinction between Kant’s perfect and imperfect duties, and how they result from his moral philosophy. Next, I summarize Smith’s two major perspectives on human behavior, as presented in The Theory of Moral Sentiments and The Wealth of Nations, and discuss the apparent conflict between them. Finally, I use Kant’s two types of duties, along with his concept of the kingdom of ends, to explicate my interpretation of the relationship between Smith’s two strains of thought. By explaining these dual aspects of Kant’s ethical system in relation to Smith, I hope to give a new perspective on the apparent duality in Smith’s thought, as well as help bring out the oft-neglected social aspects of Kant’s.     

Stability of the cooperative equilibrium in N-person prisoners' dilemma with sequential moves

Summary. Nishihara [3] showed that N-person prisoners' dilemma has a cooperative Nash equilibrium, if the players decide their actions sequentially in the order determined by Nature under a certain information structure, and if each player's payoffs satisfy a certain inequality. This paper examines the stability of this cooperative equilibrium against two matters: players' slight mistakes and deviations by coalitions. The main results are as follows: (i) if the inequality on each player's payoffs strictly holds, then the cooperative equilibrium is a strictly proper equilibrium; (ii) if N≤3, and if full cooperation is Pareto efficient in N-person prisoners' dilemma, then the cooperative equilibrium is a strong Nash equilibrium; (iii) the cooperative equilibrium is in general a coalition-proof Nash equilibrium. Received: June 23, 1997; revised version: December 2, 1997     

From ultimatum to Nash bargaining: Theory and experimental evidence

We consider a sequential two-party bargaining game with uncertain information transmission. When the first mover states her demand she does only know the probability with which the second mover will be informed about it. The informed second mover can either accept or reject the offer and payoffs are determined as in the ultimatum game. Otherwise the uninformed second mover states his own demand and payoffs are determined as in the Nash demand game. In the experiment we vary the commonly known probability of information transmission. Our main finding is that first movers’ and uninformed second movers’ demands adjust to this probability as qualitatively predicted, that is, first movers’ (uninformed second movers’) demands are lower (higher) the lower the probability of information transmission. JEL Classification C72 · C78 · C92     

Program equilibrium

In a computerized setting, players' strategies can be implemented by computer programs, to be executed on a shared computational devise. This situation becomes typical to new Internet economies, where agent technologies play a major role. This allows the definition of a program equilibrium. Following the fundamental ideas introduced by von Neumann in the 1940s (in parallel to his seminal contribution to game theory), a computer program can be used both as a set of instructions, as well as a file that can be read and compared with other files. We show that this idea implies that in a program equilibrium of the one-shot prisoners dilemma mutual cooperation is obtained. More generally, we show that the set of program equilibrium payoffs of a game coincides with the set of feasible and individually rational payoffs of it.     

Paying attention to payoffs in analogy-based learning

The analogy-based expectation equilibrium, or simply analogy equilibrium, analyzes equilibrium stereotypes by imposing consistency of infinitely large action samples with the expectation that broad classes of opponent types behave identically. This paper introduces the payoff-confirming analogy equilibrium (PAE) to refine the set of analogy equilibria. The concept imposes additionally that sample marginal of own payoffs be consistent with one’s expectations. Robust incorrect equilibrium stereotypes, i.e. non-Bayesian Nash PAE are shown to exist. General conditions are given for the prevalence of such stereotypes under correct expectations on exogenous uncertainty. In monotone selection games susceptible to winner’s curse, naive behavioral equilibrium leading to aggravation of adverse selection has been shown to match plausible informational assumptions of experienced, but behaviorally biased, equilibrium play. Here, behavioral equilibrium is matched with a corresponding PAE with an incorrect prior and correct prior is shown to imply correct overall expectations.     

Reciprocity in evolving social networks

We study the viability of conditional cooperation in a dynamically evolving social network. The network possesses the small world property, with high clustering coefficient but low characteristic path length. The interaction among linked individuals takes the form of a multiperson prisoners’ dilemma, and actions can be conditioned on the past behavior of one’s neighbors. Individuals adjust their strategies based on performance within their neighborhood, and both strategies and the network itself are subject to random perturbation. We find that the long-run frequency of cooperation is higher under the following conditions: (i) the interaction radius is neither too small nor too large, (ii) clustering is high and characteristic path length low, (iii) the mutation rate of strategies is small, and (iv) the rate of adjustment in strategies is neither too fast nor too slow.

中国农产品产业内贸易现状分析

By using HS classification, the author has divided total agricultural products into 24 categories. The paper calculated the G-L intra-industry trade index, Brülhart marginal intra-industry trade index, and Thom & McDowell marginal industry trade index for each type of agricultural products during the period from 1996 to 2005 in China. The conclusion shows the overall level of agricultural intra-industry trade is relatively low, and Brülhart index indicates China’s agricultural products decades of improvement mainly from inter-industry trade, at the same time Thom & McDowell index shows that China’s agricultural intra-industry trade growth is mainly from the growth of vertical intra-industry trade. __________ Translated from Guoji maoyi wenti 国际贸易问题 (Journal of International Trade), 2008, (1): 14–20     

Menger’s causal-realist analysis in modern economics

Carl Menger pioneered a unique theoretical research method which served as the foundation of the early Austrian school of economics. Menger’s causal-realist analysis was revived and formalized just before and after World War 2 by Ludwig von Mises as the “praxeological method.” Murray Rothbard, a student of von Mises’, utilized the method in formulating a comprehensive system of economic theory in his treatise, Man Economy, and State published in the early 1960s. Rothbard’s treatise became the foundational work for the “Austrian revival” in the 1970s. In this paper, we address several issues related to the role of Menger’s method in modern economics. First, ample evidence is adduced that von Mises and Rothbard each expressed a surprising ambivalence with respect to his own work in relation to the early Austrian school. Second, von Mises viewed Rothbard’s treatise as beginning a new epoch in economic theory. Third, contrary to the conventional view, a careful analysis of his treatise shows that Rothbard drew heavily on the contemporary neoclassical literature in developing his theoretical system and that his intent was never to set up a heterodox movement to challenge mainstream economics. Rather, his main aim was to consistently apply the praxeological method to rescue economics from what he considered the alien methodology of positivism, which was imported into economics after World War 2. Lastly, I will tentatively suggest that the term “Austrian economics” as the designation for the intellectual movement that coalesced in the early 1970s may now have outlived its usefulness. This term, which initially served an important strategic purpose in promoting the revival of the broad Mengerian tradition, may have come to obscure the meaning and importance of the praxeological research paradigm that Menger originated.     

Does financial development promote International trade?

Using China’s panel data of 30 provinces during 1990–2003, this paper attempts to explore a possible link between financial development and China’s foreign trade. Four indicators are used to identify the role of financial development, which capture both the scale and efficiency feature of China’s regional financial development. The effects of other variables are also investigated, including traditional factor endowments, foreign direct investment, infrastructure and institutional quality, etc. In general, the estimation results suggest that financial development has a quantitatively large and robust effect on China’s manufactured goods trade, among which the financial efficiency indicators play a more significant role in promoting manufactured goods trade than those scale indicators. Sensitivity estimations show that the effect of financial development on China’s total trade essentially differs from that on trade in manufactured goods.      

Long-term relationships as safeguards

We analyze a repeated prisoners’ dilemma game played in a community setting with heterogeneous types. The setting is such that individuals choose whether to continue interacting with their present partner, or separate and seek a new partner. Players’ types are not directly observed, but may be imperfectly inferred from observed behavior. We focus on a class of equilibria that satisfy zero tolerance and fresh start. We find that the punishment for defecting and the reward for cooperating are driven by the formation and the dissolution of long-term, high-paying relationships: an individual who defects, aborts a long-term relationship that he is in, or that he might have entered into, is thrown into short-term interactions with individuals who are likely to defect and, consequently, receives low payoffs. On the flip side, an individual who cooperates, enters into or prolongs a long-term interaction with a partner who cooperates and, consequently, receives high payoffs.     

Interest Groups, Trade Liberalization, and Environmental Standards

In considering a country that imposes a minimum standard on an imported polluting good, which generates negative consumption externalities, we construct a common-agency model, in which a domestic environmental group and a foreign industrial lobby can influence the formation of the minimum standard by providing political contributions to the government. This paper investigates the effects of trade liberalization on the political equilibrium environmental standard, the pattern of trade, environmental disutility, and social welfare. We find that trade liberalization tightens the minimum standard, decreases imports of the polluting good, and reduces environmental disutilities. The importing country’s social welfare, however, does not necessarily increase with trade liberalization. The weaker the environmental group’s lobbying efficiency, or the stronger the foreign firm’s lobbying efficiency, the more likely it is that trade liberalization will enhance the importing country’s welfare.     

A decomposition algorithm for N-player games

An N-player game can be decomposed by adding a coordinator who interacts bilaterally with each player. The coordinator proposes profiles of strategies to the players, and his payoff is maximized when players’ optimal replies agree with his proposal. When the feasible set of proposals is finite, a solution of an associated linear complementarity problem yields an equilibrium of the approximate game and thus an approximate equilibrium of the original game. Computational efficiency is improved by using vertices of a triangulation of the players’ strategy space for the coordinator’s pure strategies. Computational experience is reported.     

The semantics of market and civil society: a bird’s eye view of Robert Sugden’s contribution to social sciences

In this article, we discuss some key aspects of Robert Sugden’s contribution to social sciences. We focus on both his inclination to consider social orders compatible with the real distribution of knowledge in society and his idea that the market is better seen as a network of opportunities for mutual advantage.