Simultaneous inter- and intra-group conflicts

This paper models the trade-off between production and appropriation in the presence of simultaneous inter- and intra-group conflicts. The model exhibits a ‘group cohesion effect’: if the contest between the groups becomes more decisive, the players devote fewer resources to the intra-group conflict. Moreover, there is also a ‘reversed group cohesion effect’: if the intra-group contests become less decisive, the players devote more resources to the inter-group contest. The model also sheds new light on normative questions. I derive exact conditions for when dividing individuals into more groups leads to more productive and less appropriative activities. Moreover, I show that there is an optimal size of the organization which is determined by a trade-off between increasing returns to scale in production and increasing costs of appropriative activities. I want to thank Paul Heidhues, Kai Konrad, Thomas Kittsteiner, Klaas Staal, an anonymous referee, and in particular Dan Kovenock for very helpful comments and suggestions. Any remaining errors are mine. Financial support from the Deutsche Forschungsgemeinschaft through SFB/TR 15 is gratefully acknowledged.     

Appropriation,Formal and Informal Sectors,and Efficient Endowment Distribution

By adding an informal sector whose output is not subject to appropriative interactions and assuming complementarity in the inputs for market production, this paper investigates how possible asymmetries in conflict affect the allocation of resources. It is shown that when the existing gap in relative appropriative skills is being closed, more resources are allocated to appropriative activities in the economy. We are, in this case, more likely to see a reduction in market activities but an increase in home activities. A poorer party is a natural producer rather than a natural fighter, which is the usual characterization of a less endowed party in the conflict analysis. By conducting a welfare analysis, this paper shows that a market-output-maximizing initial distribution of resources endowment is such that when one party has a comparative advantage in market production over appropriation, its initial fraction of total resource endowment should be greater than its relative productivity in market production.     

Conflict diamonds

‘Conflict diamonds’ refer to the fatal role that diamonds are believed to have played in several African conflicts. The article analyzes the impact of diamond rents on economic growth in light of the broader, previously discovered empirical finding of a ‘curse of natural resources.’ By extending the theory of appropriative conflict, a predator–prey game is outlined in which a rebel chooses between peaceful production and predation on natural resources controlled by the ruler. It is shown that whereas an increase in natural resources will increase the ruler's public utility investments, it might also lead to a crowding-out of labor from the formal sector to the appropriative struggle, which depresses growth. As predicted by the model, a cross-country regression analysis suggests that diamond abundance has a negative relationship with economic growth in countries with weak institutions.     

Reputation,Social Identity and Social Conflict

We interpret the psychology literature on social identity and examine its implications. We model a population of agents from two exogenous and well defined social groups. Agents are randomly matched to play a reduced‐form bargaining game. We show that this struggle for resources drives a conflict through the rational destruction of surplus. We assume that the population contains both rational players and behavioral players. Behavioral players aggressively discriminate against members of the other social group. The existence and specification of the behavioral player is motivated by the social identity literature. For rational players, group membership has no payoff‐relevant consequences. We show that rational players can contribute to the conflict by aggressively discriminating and that this behavior is consistent with existing empirical evidence. Our paper relates to the empirical literature which finds that social heterogeneity tends to be increasing in economic variables which we interpret as indicating inefficiency. We provide an explanation that, as social groups compete for surplus, disagreement and inefficiency can result. Our work also relates to the social conflict literature, which examines the relationship between macro level factors such as unemployment and civil disturbances. This literature finds that the amount of social conflict tends to be increasing in the inequitability of the environment.     

Contests with size effects through costs

Eggert and Kolmar [Eggert, W., Kolmar, M., in press. Contests with size effects. European Journal of Political Economy.] examine the effects of group size on individual and aggregate payoffs in contests where prizes increase in the number of players. In a reconsideration of their paper, this note examines contests in which the unit cost of effort decreases in the number of players. In contests for fixed prizes, an increase in the number of players decreases individual and aggregate payoffs. In contests in which players face a trade-off between appropriative and productive investments, an increase in the number of players decreases individual payoffs while increasing aggregate payoffs.     

Scarcity and appropriative competition

This paper formalizes the commonsensical hypothesis that resource scarcity causes a large allocation of time and effort to appropriative competition. Our main innovation is to model explicitly the positive intertemporal effect of consumption on the probability of survival. The critical assumption is that this effect becomes stronger as resources become scarcer. We also show that anticipated future resource abundance increases the incremental value of survival and, consequently, amplifies the current allocation of time and effort to appropriative competition. Interestingly, if resources are currently scarce, then larger anticipated future abundance can cause a big enough increase in the time and effort allocated to appropriative competition to result in a decrease in the sum of current and expected future utility, a “paradox of anticipated abundance”.     

Do people who care about others cooperate more? Experimental evidence from relative incentive pay

We experimentally study ways in which social preferences affect individual and group performance under indefinitely repeated relative incentives. We also identify the mediating role that communication and leadership play in generating these effects. We find other-regarding individuals tend to depress efforts by 15% on average. However, selfish individuals are nearly three times more likely to lead players to coordinate on minimal efforts when communication is possible. Hence, the other-regarding composition of a group has complex consequences for organizational performance.     

The Erosion and Sustainability of Norms and Morale

I examine why the performance of an organization is often subject to gradual erosion. I assume that players are motivated partly by psychological factors, norms and morale, and that they are willing to exert extra efforts if others do so. I show that repeated random shocks induce the erosion of the extra efforts supported by norms and morale, but they do not completely decay; in the long run a certain range of efforts are sustainable. Hence different organizations typically enjoy diverse norms and morale, which persist for a long time, in the vicinity of the equilibrium determined by material incentives.     

Destructive Entrepreneurship: The Cost of the Mafia for the Legal Economy

This article focuses on the infiltration of legitimate businesses by the mafia and on the existence of “legal mafia-owned enterprises” (i.e., legal, declared enterprises owned — directly or indirectly — by mafiosi). Crime economics often limits itself to the destructive aspects stemming from merely illegal activities. Mafia investments in the legal economy and mafia entrepreneurship are also an underestimated source of latent conflict that is costly to the economy and society. This article shows that mafia-owned legal enterprises establish a lasting, unproductive, and even destructive entrepreneurship. The mafia strives to create an artificial scarcity that affects only its non-members, and thus the mafia manages to dominate markets and other entrepreneurs. The mafia then turns from its initial appropriative functions into a rule-producing function in order to shape markets. More specifically, the mafia asserts itself as a competing sovereign thanks to its power to withhold resources obtained through property over productive entities.     

Egalitarianism and Efficiency in Repeated Symmetric Games

We analyze the symmetric equilibria of repeated symmetric games where there is a conflict of interests over equilibria—the battle-of-the-sexes or the hawk–dove game are key examples. If one restricts attention to symmetric equilibria, efficient equilibria must be egalitarian. For finitely repeated games, and generic discount factors, there is a unique outcome path which ensures efficiency within the class of symmetric equilibria. This is also true for the infinitely repeated games if the players are sufficiently impatient. Journal of Economic Literature Classification Numbers: C72, C73.     

Network formation and social coordination

This paper develops a simple model to examine the interaction between partner choice and individual behavior in games of coordination. An important ingredient of our approach is the way we model partner choice: we suppose that a player can establish ties with other players by unilaterally investing in costly pairwise links. In this context, individual efforts to balance the costs and benefits of links are shown to lead to a unique equilibrium interaction architecture. The dynamics of network formation, however, has powerful effects on individual behavior: if costs of forming links are below a certain threshold then players coordinate on the risk-dominant action, while if costs are above this threshold then they coordinate on the efficient action. These findings are robust to modifications in the link formation process, different specifications of link formation costs, alternative models of mutations as well as the possibility of interaction among indirectly connected players.     

The evolution of cooperation through imitation

We study evolutionarily stable outcomes for a class of games that admit cooperation and conflict as possible Nash equilibria. We make use of two ideas: existing strategies are more likely to be imitated than new strategies are to be introduced; players are able to identify opponents' behavior prior to interaction. The long-run evolutionary limit is efficient for the case of perfect recognition of opponents' behavior. For the case of imperfect recognition, efficiency is not achieved and long-run outcomes are more efficient the more accurate is the information. Strategies that emerge in the long run are those where players reward opponents who are likely to play the same way, and punish opponents who are likely to play differently.     

PEER TRANSPARENCY IN TEAMS: DOES IT HELP OR HINDER INCENTIVES?*

In a joint project involving two players of a two‐round effort investment game with complementary efforts, transparency, by allowing players to observe each other’s efforts, achieves at least as much, and sometimes more, collective and individual efforts relative to a nontransparent environment. Without transparency multiple equilibria can arise, and transparency eliminates the inferior equilibria. When full cooperation arises only under transparency, it occurs gradually: No worker sinks in the maximum amount of effort in the first round, preferring instead to smooth out contributions over time. If the players’ efforts are substitutes, transparency makes no difference to equilibrium efforts.     

Finitely repeated games with monitoring options

We study finitely repeated games where players can decide whether to monitor the other players? actions or not every period. Monitoring is assumed to be costless and private. We compare our model with the standard one where the players automatically monitor each other. Since monitoring other players never hurts, any equilibrium payoff vector of a standard finitely repeated game is an equilibrium payoff vector of the same game with monitoring options. We show that some finitely repeated games with monitoring options have sequential equilibrium outcomes which cannot be sustained under the standard model, even if the stage game has a unique Nash equilibrium. We also present sufficient conditions for a folk theorem, when the players have a long horizon.     

A learning-based model of repeated games with incomplete information

This paper tests a learning-based model of strategic teaching in repeated games with incomplete information. The repeated game has a long-run player whose type is unknown to a group of short-run players. The proposed model assumes a fraction of ‘short-run’ players follow a one-parameter learning model (self-tuning EWA). In addition, some ‘long-run’ players are myopic while others are sophisticated and rationally anticipate how short-run players adjust their actions over time and “teach” the short-run players to maximize their long-run payoffs. All players optimize noisily. The proposed model nests an agent-based quantal-response equilibrium (AQRE) and the standard equilibrium models as special cases. Using data from 28 experimental sessions of trust and entry repeated games, including 8 previously unpublished sessions, the model fits substantially better than chance and much better than standard equilibrium models. Estimates show that most of the long-run players are sophisticated, and short-run players become more sophisticated with experience.     

Resources and conflict in the Caspian Sea

The management of resources can shape or alleviate conflict. This article examines the case of the Caspian Sea as littoral states vie for oil fields in the transboundary water body. These five states have promoted conflicting proposals for the division of Caspian resources and are staking their claims through a mix of diplomatic efforts, international agreements, commercial contracts and militarization. Geoeconomic power has not fully surpassed more traditional, military control of territory in this context which continues to be complex on several geopolitical scales.     

Cooperative behavior and the frequency of social interaction

We report results from an experiment that examines play in an indefinitely repeated, two-player Prisoner's Dilemma game. Each experimental session involves N subjects and a sequence of indefinitely repeated games. The main treatment consists of whether agents are matched in fixed pairings or matched randomly in each indefinitely repeated game. Within the random matching treatment, we elicit player's strategies and beliefs or vary the information that players have about their opponents. Contrary to a theoretical possibility suggested by Kandori [1992. Social norms and community enforcement. Rev. Econ. Stud. 59, 63–80], a cooperative norm does not emerge in the treatments where players are matched randomly. On the other hand, in the fixed pairings treatment, the evidence suggests that a cooperative norm does emerge as players gain more experience.     

A Folk Theorem for Repeated Sequential Games

We study repeated sequential games where players may not move simultaneously in stage games. We introduce the concept of effective minimax for sequential games and establish a Folk theorem for repeated sequential games. The Folk theorem asserts that any feasible payoff vector where every player receives more than his effective minimax value in a sequential stage game can be supported by a subgame perfect equilibrium in the corresponding repeated sequential game when players are sufficiently patient. The results of this paper generalize those of Wen (1994), and of Fudenberg and Maskin (1986). The model of repeated sequential games and the concept of effective minimax provide an alternative view to the Anti–Folk theorem of Lagunoff and Matsui (1997) for asynchronously repeated pure coordination games.     

A folk theorem for minority games

We study a particular case of repeated games with public signals. In the stage game an odd number of players have to choose simultaneously one of two rooms. The players who choose the less crowded room receive a reward of one euro (whence the name “minority game”). The players in the same room do not recognize each other, and between the stages only the current majority room is publicly announced. We show that in the infinitely repeated game any feasible payoff can be achieved as a uniform equilibrium payoff, and as an almost sure equilibrium payoff. In particular we construct an inefficient equilibrium where, with probability one, all players choose the same room at almost all stages. This equilibrium is sustained by punishment phases which use, in an unusual way, the pure actions that were played before the start of the punishment.     

Non-convexities and the gains from concealing defenses from committed terrorists

How should countries defend against committed terrorists who attack until defeated? We identify a fundamental non-convexity—one only needs to defeat the terrorist once. Consequently, provided a country values targets similarly, it should conceal defenses and allocate defense resources randomly.