title: Learning to coordinate in a complex and nonstationary world.
abstract: We study analytically and by computer simulations a complex system of adaptive agents with finite memory. Borrowing the framework of the minority game and using the replica formalism we show the existence of an equilibrium phase transition as a function of the ratio between the memory lambda and the learning rates Gamma of the agents. We show that, starting from a random configuration, a dynamic phase transition also exists, which prevents agents from reaching optimal coordination. Furthermore, in a nonstationary environment, we show by numerical simulations that the phase transition becomes discontinuous.
authors.affiliation: Istituto Nazionale per la Fisica della Materia, Unità di Trieste-SISSA, I-34014 Trieste, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Marsili
authors.forename: R
authors.initials: R
authors.lastname: Mulet
authors.forename: F
authors.initials: F
authors.lastname: Ricci-Tersenghi
authors.forename: R
authors.initials: R
authors.lastname: Zecchina
mesh_terms: D005716:Game Theory; D006801:Humans; D007858:Learning; D008568:Memory; D008962:Models, Theoretical; D012917:Social Adjustment