A Synthesis Between Mental Attitudes and Social Commitments in Agent Communication Languages

There are two main traditions in defining a semantics for agent communication languages, based either on mental attitudes or on social commitments. In this paper we show how the role metaphor can be used to bridge the gap between these two approaches. First, we show how dialogues can be modelled as games - a form of normative systems - and how mental attitudes can be attributed not only to agents, but also, in a public manner, to the roles of the game. The dialogue moves allow an agent playing a role to modify the rolesý mental states, as specified by the counts-as conditionals (also known as constitutive norms) defining the game. The player of a role is expected to act as if it has the mental attitudes attributed to its role during the dialogue and to prevent its roleýs mental attitudes from becoming incoherent, as it does for its own private mental attitudes. Secondly, we show how roles as descriptions of expected behavior maintain the normative character of social semantics. Due to the bridge between the two approaches, results and tools from one approach can be used in the other one.