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pragmatics of utterances in cooperative dialogues. The maxims express the cooperation
principle:
Make your conversational contribution such as is required, at the stage at which
it occurs, by the accepted purpose or direction of the talk exchange in which
you are engaged,
which arguably must be observed if misunderstandings and conversational breakdown
are to be avoided. Relevance (which may be dependent on the dialogue type and its
state) is our main concern here.
Thus Bert begins in B1 by stating that Burger World satisfies two criteria. Burger
World is not chosen at random but is Bert's currently preferred option, the one which
the Thai Palace must overcome. The criteria are those which Bert believes Burger World
does, and the Thai Palace does not, satisfy. Thus in Wilma's reply she can improve her
case by stating that one of the criteria is satisfied by the Thai Palace. Once a criterion
is put into play, it is considered for both options, thus verifying any existing beliefs
Bert may have about the options. In B2 Bert asks a question. This again is not chosen
at random but concerns a criterion which, if satisfied, would put Burger World beyond
reach. Wilma can, however, truthfully say that it does not satisfy this criterion, but that
the Thai Palace does. Bert now draws the dialogue to a close since he has sufficient
knowledge of the criteria relating to the two options relevant to him, according to his
preferences. He does not ask about licencing because that cannot restore Burger World's
lead. In this dialogue features of the Thai Palace that make it attractive to Wilma are
not even mentioned, while she supplies information about a feature to which she is
indifferent: Bert is the sole arbiter of what makes the restaurant good (in complete
contrast to deliberation). Bert could not ask about another criterion without misleading
Wilma by
conversationally implying
that he valued a fourth criterion enough to overturn
his current view, which would prolong the dialogue to no useful purpose. Note also the
asymmetry: Wilma's criteria may determine her recommendation, but play no part in
the dialogue unless they are shown to be valued by Bert.
The dialogue is not, however, as efficient as it might be. Given his weights, if Bert
discovered that either restaurant was, and the other was not, of good quality, he could
stop immediately, since this criterion carries more weight than the other three combined.
Thus Bert's best initial question would have been B2, with Wilma's reply in W3 enough
to resolve the discussion. We could extend our notion of conversational implicature to
suggest that mentioning a criterion means not only that it matters to the persuadee but
additionally that there are no more important criteria not yet mentioned. This is what
we will do in the algorithm developed in the next section. As we will see in section 5,
this algorithm, based on conversational implicature, is optimal in terms of minimising
the expected exchange of information.
Note also that Bert's strategy is good only with regard to open persuasion. Had this
been a partial persuasion situation, Bert's question in B2 could only have received the
response that the Thai Palace was good. Since Wilma is not obliged to tell the whole
truth, even if she had believed that Burger World was good, she would have remained
silent on that point, and indeed on all positive features of Burger World. Wilma answers
the question only if the answer does not improve Bert's assessment of that restaurant.
In a partial persuasion, therefore, Bert will ask only whether the Thai Palace is good.
