Group formation and Mass Media effects in Cultural Dynamics: The power of being subtle

A system of agents interacting in a network with a globalization-polaritation transition is studied in the context of a cultural dissemination model. We consider different types of fields interpreted as forms of mass media acting on the system. Both for autonomous and external fields, polarization grows in the system when the probability of the agents to interact with the external field is increased. There exists a threshold value of this probability beyond which the system remains always polarized. The domain of parameters of the global regime is larger for nonuniform local mass media than for uniform mass media or external fields. However, the zero field limit is discontinuous. For vanishingly small probability of interaction with the external field, autonomous or external fields are able to order a system that would fall in a polarized phase under local interactions of the agents alone. We also consider the formation of groups when the agents are allowed to choose partners taking into account their degree of similarity. We find that in the globalized phase a large cluster is formed with all agents sharing the same cultural traits. In the polarized phase, several cultural groups coexist due to the formation of cultural barrier