|By:||Boris van Leeuwen (University of Amsterdam)
Theo Offerman (University of Amsterdam)
Arthur Schram (University of Amsterdam)
We investigate contributions to the provision of public goods on a network when efficient provision requires the formation of a star network. We provide a theoretical analysis and study behavior in a controlled laboratory experiment. In a 2×2 design, we examine the effects of group size and the presence of (social) benefits for incoming links. We find that social benefits are highly important. They facilitate convergence to equilibrium networks and enhance the stability and efficiency of the outcome. Moreover, in large groups social benefits encourage the formation of superstars: star networks in which the core contributes more than expected in the stage-game equilibrium. We show that this result is predicted by a repeated game equilibrium.
|Keywords:||Network formation, networked public goods, peer production, social benefits, open source software|
|JEL:||C91 D85 H41|
|By:||Bryan S. Graham|
Social and economic networks are ubiquitous, serving as contexts for job search, technology diffusion, the accumulation of human capital and even the formulation of norms and values. The systematic empirical study of network formation – the process by which agents form, maintain and dissolve links – within economics is recent, is associated with extraordinarily challenging modeling and identification issues, and is an area of exciting new developments, with many open questions. This article reviews prominent research on the empirical analysis of network formation, with an emphasis on contributions made by economists.
|JEL:||C23 C25 D85|
Gary Charness, Francesco Feri, Miguel A. Meléndez-Jiménez, and Matthias Sutte (2012) “Equilibrium Selection in Experimental Games on Networks." working paper, Department of Economics, UC Santa Barbara. [pdf] [ideas]
Abstract. We study behavior and equilibrium selection in experimental network games. We vary two important factors: (a) actions are either strategic substitutes or strategic complements, and (b) subjects have either complete or incomplete information about the structure of a random network. Play conforms strongly to the theoretical predictions, providing an impressive behavioral confirmation of the Galeotti, Goyal, Jackson, Vega-Redondo, and Yariv (2010) model. The degree of equilibrium play is striking, even with incomplete information. We find that under complete information, subjects typically play the stochastically-stable (inefficient) equilibrium when the game involves strategic substitutes, but play the efficient one with strategic complements. Our results suggest that equilibrium multiplicity may not be a major concern Subjects’ actions and realized outcomes under incomplete information depend strongly on both the degree and the connectivity. When there are multiple equilibria, subjects begin by playing the efficient equilibrium, but eventually converge to the inefficient one.
We provide an overview on networks in economics. We first look at the theoretical aspects of network economics using a game-theoretical approach. We derive some results on games on networks and network formation. We also study what happens when agents choose both links and actions. We then examine how these models can be used to address some applied and empirical-relevant questions by mainly focusing on labor-market networks and crime networks. We provide some empirical evidence on these two types of networks and address some policy implications of the models.
|Keywords:||criminal networks; games on networks; labor networks; network formation; Social networks|
Sara Gabriela Castellanos Pascacio
Alma L. García-Almanza
We investigate the payment card’s adoption rate under consumers’ and merchants’ awareness of network externalities, given two levels of Interchange Fees in a multiagent card market. For the purpose of our research, in multiple instances of the model (scenarios) the investigated effects are analyzed over the complete process of adoption, until the market’s saturation point is achieved. For each scenario, a comparison is made between two different levels of Interchange Fees and different degrees of consumers’ and merchants’ awareness. We model explicitly the interactions between consumers and merchants at the point of sale. We allow card issuers to charge consumers with fixed fees and provide net benefits from card usage, whereas acquirers can charge fixed and transactional fees to merchants.
|Keywords:||Two-sided markets, financial services, network formation.|