Information sources: Trust and meta-trust dimensions

We start from the claim that trust in information sources is in fact just a kind of social trust. We are interested in the fact that the relevance and the trustworthiness of the information acquired by an agent X from a source F, strictly depends and derives from the X's trust in F with respect the kind of that information. Even if, of course, we have also to consider the potential (positive and negative) interferences between this information and the previous X's beliefs. In this paper, we analyze the dierent dimensions of trust in information sources and formalize the degree of subjective certainty or strength of the X's belief P, considering three main factors: the X's trust about P just depending from the X's judgement of the source's competence and reliability; the sources' degree of certainty about P; and the X's degree of trust that P derives from that given source. Finally we present a computational approach based on fuzzy sets and some interesting examples of significant cases.