Formal Handling of Threats and Rewards in a Negotiation Dialogue

Argumentation plays a key role in finding a compromise during a negotiation dialogue. It may lead an agent to change its goals/ preferences and force it to respond in a particular way. Two types of arguments are mainly used for that purpose: threats and rewards. For example, if an agent receives a threat, this agent may accept the offer even if it is not fully “acceptable” for it (because otherwise really important goals would be threatened). The contribution of this paper is twofold. On the one hand, a logical setting that handles these two types of arguments is provided. More precisely, logical definitions of threats and rewards are proposed together with their weighting systems. These definitions take into account that negotiation dialogues involve not only agents’ beliefs (of various strengths), but also their goals (having maybe different priorities), as well as the beliefs about the goals of other agents. On the other hand, a “simple” protocol for handling such arguments in a negotiation dialogue is given. This protocol shows when such arguments can be presented, how they are handled, and how they lead agents to change their goals and behaviors.