Recommendation of categories in an agents world: The role of (not) local communicative environments

Due to Internet and social media web, the world as we know it is deeply changing integrating two different aspects of the social interaction: the one that develop in the real world and the one that develop in web society. In this paper we focus on the importance of generalized knowledge (agents\´ categories) in order to understand how much it is crucial in these two worlds. The cognitive advantage of generalized knowledge can be synthesized in this claim: "It allows us to know a lot about something/somebody we do not directly know". At a social level this means that I can know a lot of things on people that I never met; it is social "prejudice" with its good side and fundamental contribution to social exchange. In this study we will analyse and present some differences between the social relationships in the two worlds and how they influence categories\´ reputation. On this basis, we will experimentally inquire the role played by categories\´ reputation with respect to the reputation and opinion on single agents: when it is better to rely on the first ones and when are more reliable the second ones. We will consider these simulations for both the two kind of world, investigating how the parameters defining the specific environment (number of agents, their interactions, transfer of reputation, and so on) determine the use of categories\´ reputation and trying to understand how the role played by categories will be important in the new digital worlds.