Demonstration 2: Holding the floor

In this demonstration, it is shown that the planner can effectively "hold the floor" in a negotiation. Holding the floor is when an agent decides whether to make a contribution to the dialogue, or whether to pass the turn to another agent, expecting that his contribution is more important. Such a decision cannot be made without considering the value of information. It is known that speakers use various cues to determine the passing of a turn [61], and that humans are very good at seamlessly coordinating their turns. Value of information might turn out to be useful in dialogue systems for deciding when to take the floor, and equally well for predicting when a conversational partner might want to take the floor, thus enabling coordination. Holding the floor is quite similar to the taking of initiative that was illustrated in both of the examples in chapter 4, where an agent must decide whether to contribute to the task, or to decline and allow the other agent to decide whether to contribute.

For the demonstration, an example problem was constructed in which agent 1 needs to know whether agent 2 has fruit, so that it can safely use up the eggs without spoiling agent 2's dessert plans. However, if agent 1 doesn't have any eggs, the question is not relevant. The expectation is that when agent 2 does not believe that agent 1 has eggs, then agent 1 needs to be forceful in asking, since agent 2, thinking the information is worthless, will not volunteer it without being asked. On the other hand, if agent 2 does believe that agent 1 has eggs, it will give the information without being asked. Therefore, agent 1 would not need to use an ask - it can just pass and wait for a tell, with less cost. Therefore agent 1 must make a decision between contributing to the negotiation with an ask, and passing to agent 2. The plan library for the problem is given in figure 5.7, while the corresponding game tree is given in figure 5.8.

The utility function for the problem was defined as:

utility(make-omelette,150).
utility(make-fish,100).
utility(make-cake,100).
utility(make-fruit-salad,100).

Figure 5.7: Plan library for "holding the floor" example

Figure 5.8: Game tree for the domain-level plan

Figure 5.9: Game tree for the negotiation plan