Marco Colombetti

When they interact in everyday situations, people constantly create new fragments of social reality: they do so when they make promises or agreements, but also when they submit requests or answer questions, when they greet each other or express gratitude. This type of social reality ‘in the small,’ that we call interpersonal reality, is deontic in nature as all other kinds of social reality; what makes it somewhat special is that its deontology applies to the very same persons who create it through a process of intentional collaboration. Aim of this paper is to show that interpersonal reality can be accounted for in terms of a suitable concept of interpersonal responsibility. To this purpose we first discuss the deontology that is constitutive of interpersonal reality; then we show how such deontology can be entailed by relationships of interpersonal responsibility; and finally we argue that these relationships are created by executing suitable communicative acts, understood as actions performed with a reflexive communicative intention.

Software agents’ ability to interact within different open systems, designed by different groups, presupposes an agreement on an unambiguous definition of a set of concepts, used to describe the context of the interaction and the communication language the agents can use. Agents’ interactions ought to allow for reliable expectations on the possible evolution of the system; however, in open systems interacting agents may not conform to predefined specifications. A possible solution is to define interaction environments including a normative component, with suitable rules to regulate the behaviour of agents. To tackle this problem we propose an application-independent metamodel of artificial institutions that can be used to define open multiagent systems. In our view an artificial institution is made up by an ontology that models the social context of the interaction, a set of authorizations to act on the institutional context, a set of linguistic conventions for the performance of institutional actions and a system of norms that are necessary to constrain the agents’ actions.

In this article we present the bases for a computational theory of the cognitive processes underlying human communication. The core of the article is devoted to the analysis of the phases in which the process of comprehension of a communicative act can be logically divided: (1) literal meaning, where the reconstruction of the mental states literally expressed by the actor takes place: (2) speaker's meaning, where the partner reconstructs the communicative intentions of the actor; (3) communicative effect, where the partner possibly modifies his own beliefs and intentions; (4) reaction, where the intentions for the generation of the response are produced; and (5) response, where an overt response is constructed. The model appears to be compatible with relevant facts about human behavior. Our hypothesis is that, through communication, an actor tries to exploit the motivational structures of a partner so that the desired goal is generated. A second point is that social behavior requires that cooperation be maintained at some level. In the case of communication, cooperation is, in general, pursued even when the partner does not adhere to the actor's goals, and therefore no cooperation occurs at the behavioral level. This important distinction is reflected in the two kinds of game we introduce to account for communication. The main concept implied in communication is that two agents overtly reach a situation of shared mental states. Our model deals with sharedness through two primitives: shared beliefs and communicative intentions.

We compare a number of influential approaches to human communication with the aim of understanding what it means for interpersonal communication to be a form of social action. In particular, we discuss the large-scale social normativity advocated by speech act theory, the view of communication as small-scale social interaction proper of Gricean approaches, and the intimate connection between communication and cooperation defended by Tomasello. We then argue in favor of a small-scale view of communication capable of accounting for the normative effects of communicative acts; to this purpose, we introduce the concept of interpersonal normativity and analyze its relationship with communicative intentions

We understand interpersonal reality as consisting of those social facts that are informally created by people for themselves in everyday interactions, and involve the collective acceptance of positive and negative deontic powers. We submit that, in the case of interpersonal reality, Gilbert’s concept of a joint commitment is a suitable view of what collective acceptance amounts to. We then argue that creating interpersonal reality, even in common everyday-life situations, typically requires conversational exchanges involving several layers of joint commitments, and in particular joint commitments to projects, joint meaning, and the joint commitments that are constitutive of conversations.

I propose a propositional modal logic of intentional communication, a circular concept which develops an idea by Airenti, Bara and Colombetti (1993). A communication operator is added to a multi-modal language of individual belief, common belief, and intention, and its possible world semantics is justified through a fixpoint construction. A normal modal system for the communication operator is defined, and shown to be sound and complete. Within this framework, I prove some properties of intentional communication and give sufficient conditions for an action to be communicative.

In this paper we outline a theory of human deontology from a naturalistic perspective. In doing so we aim to explain how human beings deal with deontic relations (like obligations and rights) thanks to a specialised psychological infrastructure, which evolved to support human cooperation. This infrastructure includes a repertoire of emotions that play a crucial role in evaluating the conformity of actions relative to a deontic relation, in displaying an agent’s attitude toward their own actions or those of their deontic partners, and in motivating suitable behavioural responses. Finally we discuss the special case of interpersonal deontology, analysing its properties and relating it to Gilbert’s concept of joint commitment.

Agent Communication Languages (ACLs) have recently acquired a primary role in open multiagent systems, which need a standard communication framework shared by all interacting heterogeneous agents. According to the most important ACL standard proposals so far, agents are supposed to carry out the communication process by performing actions of a specific type, namely, communicative acts, whose semantics is defined in terms of the agents’ mental states. Although following the mainstream guidelines inspired by the Speech Act Theory, our work illustrates an alternative model of agent communication, by shifting the focus from agents’ mental states to their social state. Taking an existing communicative act library, we provide a semantics for a significant set of acts based on the concept of commitment, and prove that our approach tackles some issues that have not been dealt with in an effective way yet and that may have hindered the rise of an universally accepted ACL standard.