The predictive role of prejudice: a computational model for using categories

Generalised knowledge allows us to know a lot about something/somebody we do not directly know: this is a great cognitive advantage. 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 paper we focus on the importance of generalised knowledge: agents' categories. In studies on trust building and dynamics the role of direct/personal experience and of recommendations and reputation is a bit overrated; while the importance of inferential processes in deriving the evaluation of trustees' trustworthiness is underestimated and not exploited. 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. This powerful inferential device has to be strongly present in WEB societies supported by MAS.