A Situation-aware and Social Computational Trust Model

Computational trust modeling is a research field with a fast growing development since the last decade, mainly in the scientific area of distributed artificial intelligence and multi-agent systems, and its potential applicability spreads from social networks to distributed resource sharing and electronic markets. The earliest approaches to computational trust addressed the development of algorithms to aggregate the evidence on any given agent under evaluation into an estimated score of this agent’s trustworthiness. More recently, the research on computational trust has shifted to the inclusion of third-party information about the trustee under evaluation, including opinions and reputation. However, one important aspect of computational trust has being neglected all these years by the majority of the scholars on computational trust, with a few relevant exceptions: trust is a social construct with a cognitive and an emotional account, and it strongly depends on the relationship existing between the agent that trusts and the one that is trusted. In this thesis, we address the topic of social trust and its consideration for application in computational trust. We first present a thorough multidisciplinary view of trust, and derive important propositions that will guide our work throughout the thesis. Based on these propositions, we present the SOLUM model, our proposal to computational trust comprised of two distinct parts. The first part is a general framework of computational trust that is based on two fundamental characteristics of trust: trust is more than trustworthiness and other important antecedents to trust, such as the truster’s disposition and emotional state, must be considered when estimation the truster’s trust; and trustworthiness is a multi-dimensional construct that includes the ability, integrity, and benevolence dimensions. This framework can be instantiated and applied to a wide range of trust-based problems and applications, and is seen here as the first main contribution of this thesis. The second part of the SOLUM model includes a set of distinct computational components that (partially) instantiate the framework, namely: