walking between free will and determinism

Walking is a fundamental activity of human beings. Any simple movement is the result of complex interactions between the external environment and the individual cognitive dynamics. The proposedmodels havemainly considered a deterministic point of view to describe the choice of the pedestrians trajectories and to study the critical congested states. But recently it has been pointed out the importance of the individual free will in determining both the microscopic pedestrian behavior and the emergent properties of the crowd dynamics. In this paper we discuss a hierarchical model for pedestrian mobility whose emergent dynamical properties are determined by the bottom-up and top-down actions among the microscopic-level (free-will level), the mesoscopic level (deterministic level) andmacroscopic level (cognitive level). The "mobbers" have an internal cognitive dynamics, performboth physical and information based interactions using a vision mechanism and are able to compute a cognitive map representation of the geometrical space. The model has been implemented in the DISTRIMOBS simulator that is designed to simulate a whole city on a distributed architecture. The main properties of the model are discussed and some applications are presented.