Giorgio Negroni

Adaptive expectations coordination in an economy with heterogeneous agents

In this paper we study expectations coordination on the stationary state in a one dimensional economy. We allow for two sources of heterogeneity : the first concerns the fundamentals of the economy, the second the adaptive learning rules. Specifically we consider heterogeneous adaptive learning within a class of constant gain learning algorithm, where the parameter of gain differ across agents. We show that these two sources of heterogeneity create difficulty to coordination.

Expectations Coordination On A Sunspot Equilibrium: An Eductive Approach

We analyze expectations coordination on a stationary sunspot equilibrium (SSE) using an eductive approach in which agents forecast the forecasts of others. This approach is grounded in some common-knowledge assumptions. We show that two institutional contexts may be envisaged; we also distinguish between stationary and nonstationary beliefs. We show that the conditions for eductive stability depend mainly on whether stationarity of beliefs is imposed. We also prove the existence of eductively stable SSEs by means of the PoincarA©â€“Hopf theorem and show that eductively stable SSEs exist in a neighborhood of some indeterminate steady states. (This abstract was borrowed from another version of this item.)

Egalitarianism: An evolutionary perspective: Egalitarianism

Two parties bargain over a pie, the size of which is determined by their previous investment decisions. Investment costs are heterogenoeus. The bargaining rule is sensitive to investment behavior. Our main result is that egalitarianism is more likely to emerge in situations in which private property over the fruits of ones own independent investment is not secured.

On the Coevolution of Social Norms in Primitive Societies

Two parties bargaining over a pie, the size of which is determined by their previous investment decisions. The bargaining rule is sensitive to investment behavior. Two games are considered. In both, bargaining proceeds according to the Nash Demand Game when a symmetric investments profile is observed. When, on the other hand, an asymmetric investments profile is observed, we assume that bargaining proceeds according to the Ultimatum Game in one case and according to a Dictator Game in the other. We hereby show that in both games when a unique stochastically stable outcome exists it supports an homogeneous behavior in the whole population both at the investment stage and at the distribution stage. A norm of investment and a norm of division must therefore coevolve in the two games, supporting both the efficient investment profile and the egalitarian distribution of the surplus, respectively. The two games differ depending on the conditions needed for the two norms to coevolve. The games are proposed to explain the social norms used in modern hunter-gatherer societies.

Egalitarianism. An evolutionary perspective

Two parties bargaining over a pie, the size of which is determined by their previous investment decisions. Investment costs are heterogeneous. The bargaining rule is sensitive to investment behavior. Two games are studied which differ for the considered sociopolitical structure: communal property in one case and private property in the other. We hereby show that in both games when a unique stochastically stable outcome exists a norm of investment and a norm of surplus division must coevolve. While the investment norm always supports the efficient investment profile, the surplus division norm may differ among these games depending on the size of investment cost gap. Under private property only the egalitarian surplus division evolves. Under communal property instead two different surplus division norms may evolve: the egalitarian one and an inegalitarian norm. We show that no cap to payoffs inequality emerges under private property while an inequality payoff cap endogenously evolves under communal property. The games have been proposed to explain the social norms used in modern hunter-gatherer societies.

On the co-evolution of investment and bargaining norms

Two parties bargaining over a pie whose size is determined by the investment decisions of both. The bargaining rule is sensitive to the investment behavior. If a symmetric investments profile is observed, bargaining proceeds according to the Nash Demand Game; otherwise bargaining proceeds according to the Ultimatum Game. We are interested in the evolutionary emergence of both an efficient investment norm and a bargaining norm. Under some conditions we prove that these norms co-evolve; when this happens they support the efficient investment and the egalitarian distribution of the surplus. In addition, when surplus requires that at least one agent invests, then either both norms co-evolve or no norm evolves.