Brown Bag Seminar: Simon Schopohl

Who matters in coordination problems on networks?

Simon Schopohl, USL-B, CORE

This paper studies a model of social interaction in a fixed network where agents play a coordination game - a game where it is optimal for a player to choose an action like most of her friends. The different actions correspond to different projects the player can invest into. A project is successful once a certain amount of players have chosen it. All players have a certain type: A player can be either an extremist for one of the projects or she can be a moderate. Extremist players only obtain utility from one project, while moderate players are ex ante indifferent between the projects. In addition, the players may also differ in their level of farsightedness: Some players cannot foresee the reactions that their actions cause while others anticipate all induced changes. We analyse the set of stable strategy profiles, i.e. the strategy profiles in which no player has any incentive to deviate to another action. We show how the set of stable strategy profiles changes if we turn a myopic player farsighted, a moderate player into an extremist or vice versa. Furthermore, we characterize the set of stable strategy profiles for common network structures.

(joint work with Ana Mauleon, Akylai Taalaibekova and VIncent Vanetelbosch)