Goal Generation and Adoption in Hierarchical Agent Models

If agents are able to exploit the resources available in a multi-agent domain they must make use of other agents to help them in their tasks. In order to do this it is important that we first of all have an understanding of agency, and then of how goals are generated and subsequently adopted by other agents. In this paper we build upon a three-tiered hierarchy which has been constructed to define objects, agents and autonomous agents, where all autonomous agents are agents, and all agents are objects. In this hierarchy, agents are viewed as objects with goals, and autonomous agents as agents with motivations. Any object may be viewed as an agent if is currently being engaged to some use, and any agent as autonomous if it has the ability to generate its own goals. This view of agency and autonomy is thus based on the generation and transfer of goals between various entities in the world. Specifically, an entity is an agent if it can be viewed as satisfying a goal. This goal must first be created and then, if necessary and appropriate, transferred to another entity. It is this adoption of goals that makes an entity change from an object to an agent, and it is the self-generation of goals that defines the autonomy of an agent. We consider the three classes of goal adoption by objects, agents and autonomous agents. The first of these is merely a question of instantiation, the second requires an understanding of the relationship of the agent to the other entities that are engaging it, and the third amounts to a question of negotiation or persuasion. In this paper we specify and describe goal generation and adoption in the context of hierarchical agent models using the Z specification language.