A guest robot acquires a right of access to a resource a host robot can access after accreditation by the host robot. The host robot accredits the guest robot on condition that the guest robot is positioned within a predetermined distance. The guest robot receives behavioral characteristic information from a server that determines behavioral characteristics of the host robot, and selects a motion in accordance with the behavioral characteristic information. A behavioral restriction that is not imposed on the host robot may be imposed on the guest robot.