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<Paper uid="P92-1020">
  <Title>WOULD I LIE TO YOU? MODELLING MISREPRESENTATION AND CONTEXT IN DIALOGUE</Title>
  <Section position="8" start_page="155" end_page="156" type="concl">
    <SectionTitle>
6. RESULTS AND DISCUSSION
</SectionTitle>
    <Paragraph position="0"> Evaluative trials for the PMM system have been aimed specifically at both the individual PMMs and the PMM model. Twenty-six different types of situations have been designed to test the PMMs' relevance, consistence, and coherence. Through these trials the individual PMMs demonstrated their integrity, and the PMM model itself was shown to be capable of working within a dialogue system architecture. Full details of evaluation methodology and results can be found in \[Gutwin 1991\].</Paragraph>
    <Paragraph position="1"> This research project has shown that PMMs can be represented for use in a tutorial dialogue system, and supports their value as a pedagogic tool.</Paragraph>
    <Paragraph position="2"> However, the foremost contribution of the PMM system to computational dialogue may be how it extends the notion of focus currently used in dialogue research. Grosz and Sidner \[1986\] see dialogue as a collection of focus spaces which shift in reaction to changes in the discourse's purposes and salient entities. This research suggests that within any of these focus spaces, there can exist a further structure: a context that provides a specific interpretation of the knowledge represented in the system. The same knowledge is &amp;quot;in focus&amp;quot; throughout the focus space, but different contexts can color or interpret that knowledge in different ways. A pedagogically motivated misrepresentation is thus a context mechanism that alters the domain knowledge for an educational purpose. It is possible that we always use  some kind of alternate interpretation or misrepresentation to mediate between our knowledge and other dialogue participants.</Paragraph>
    <Paragraph position="3"> Focusing structure has traditionally been used in interpretation: in several projects (\[Grosz 1977\], \[Sidner 1983\]), context structures are shown to be useful in tasks like pronoun resolution or anaphora resolution. Pragmatic contexts, such as those created by a PMM, can direct generation of discourse as well. They are active reflections of the larger situation, rather than local representations of dialogue structure, and they are able to alter the discourse in order to further some goal. Responding to patterns in the world outside the dialogue allows pragmatic context mechanisms such as PMMs to consider fitness and suitability of a dialogue situation in addition to a focus space's subset of goals and salient entities.</Paragraph>
    <Paragraph position="4"> Another issue of importance to this research is that of tailoring. While some existing dialogue systems tailor an explanation to the user's level of expertise (e.g. \[Paris 1989\], \[McKeown et al 1985\]), the PMM system instead tailors the domain to the learner. The PMM system does not make basic decisions about either content or delivery in a dialogue, but attempts to shape the content's representation into a form which will be best suited to the learning situation.</Paragraph>
    <Paragraph position="5"> The PMM model also touches on research into multiple representation, in that it provides a mechanism for encapsulating several different interpretations of a knowledge base. The mechanism might be able to model and administer alternate representations of other kinds as well, such as analogy.</Paragraph>
    <Paragraph position="6"> The usefulness and ubiquity of PMMs also suggests that a literal interpretation of Grice's maxims, particularly the maxim of quality, is inappropriate. Clearly, we often say things we know to be false! However, the maxim of quality can be rescued by indicating the relationship between truth and dialogue purposes: from the original, &amp;quot;do not say that which you believe to be false,&amp;quot; we create a new maxim, &amp;quot;do not say that which you believe to be false to your purposes.&amp;quot; The new maxim shifts emphasis from an absolute standard of truth in dialogue to the more pragmatic idea of truth relative to a dialogue's goals, and better reflects the way humans actually use discourse.</Paragraph>
    <Paragraph position="7"> Much remains to be accomplished in this research.</Paragraph>
    <Paragraph position="8"> There are undoubtedly other as yet undiscovered PMMs. The notion of intentional misrepresentation itself may just be an instance of a more general context mechanism that underlies all dialogue, an idea that should be explored by considering other kinds of dialogue from the perspective of PMMs, and by a closer examination of existing theories of discourse context. Finally, all of the oracles used in the PMM System should be replaced by functioning components so that a dialogue system with complete capabilities can stand alone as proof of the PMM concept.</Paragraph>
    <Paragraph position="9"> Nevertheless, this research points the way towards the possibility of a new and widely applicable mechanism for modelling dialogue.</Paragraph>
  </Section>
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