The role of polarization and hostility on equilibria in a simple class of symmetric conflict models

This study aims to provide a manageable symmetric two-players conflict model in which, defining measures for polarization and hostility, we investigate the effects of spillovers into the properties of the sets of equilibria, into the intensity of conflict, and into the endogenous changes in polarization and hostility. We show that, without spillovers, the equilibrium efforts' intensity is uniquely connected to the ratio of the marginal productivity of effort to (ex ante) polarization. Conversely, we show that negative spillovers in conflict technology can imply the non-existence of equilibria. Then, introducing spillovers in the possible outcomes of the conflict, we connect the existence of multiple symmetric and asymmetric equilibria to the intensity of growing polarization and hostility. We then investigate the different effects of marginal productivity of effort, (ex ante) polarization and rates of growth of polarization and hostility on the intensity of conflict as well as on polarization and hostility at equilibrium. The results show the crucial role played by hostility, a factor disregarded in many conflict models. Finally, we show how the results obtained by considering partial spillover effects are confirmed when the general case is taken into account.