Flexible Conversations Using Social Commitments and a Performatives Hierarchy

Abstract

In this research, we re-arrange FIPA's ACL performatives to form a subsumption lattice (ontology) and apply a theory of social commitments to achieve a simplified and observable model of agent behaviour. Using this model, we have implemented agent interaction through social commitments (or obligations) based solely on observation of messages passed between the agents (such observation is supported by the cooperation domainmechanism in our agent infrastructure system). Moreover, because the performatives are in a subsumption lattice, it is relatively easy for an observer to infer social commitment relationships even if the observer does not understand the details of messages or even the exact performatives used (so long as the observer has access to the performatives ontology). Our social commitment model can be used in agent implementation to simplify the specification and observation of agent behaviour even if the agents themselves are not implementedusing social commitments. This is accomplished through the use of commitment operatorsattached to the performatives (as policies) in the subsumption lattice. In this work, we show how FIPA's performatives can be interpreted in a theory of social commitment to allow observable social behaviour and conformance to social norms.