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<Paper uid="C92-1054">
  <Title>Redundancy in Collaborative Dialogue</Title>
  <Section position="4" start_page="0" end_page="0" type="metho">
    <SectionTitle>
4 Making Inferences Explicit
</SectionTitle>
    <Paragraph position="0"> This section discusses assumption (3) of the determistic model, namely that: Agents are logically omniscient.</Paragraph>
    <Paragraph position="1"> The following excerpt demonstrates this structure. Utterance (15) realizes la, utterance (16) realizes lb, and utterance (17) makes the inference explicit that is given in lc for the particular tax year of 1981.</Paragraph>
    <Paragraph position="3"> as long as you are not a participant in an existing pension (as) j. oh i see.</Paragraph>
    <Paragraph position="4"> well i did uork i do uork for a company that has a pension (17) h. ahh. THEN YOU'RE NOT ELIGIBLE</Paragraph>
  </Section>
  <Section position="5" start_page="0" end_page="0" type="metho">
    <SectionTitle>
FOR EIGHTY ONE
</SectionTitle>
    <Paragraph position="0"> (18) j. i see, but i am for 82 After (16), since the propositional content of (17) is inferrable, the assumption that Harry has made this inference is supported by the inf arance evidence type: bel(H, lieense(p16, p17)) \[inference\] According to the model of achieving mutual understanding that was outlined in section 3, utterance (17) provides linguistic evidence that Ilarry (h) believes that the proposition realized by utterance (16) licenses the inference of (17) in this context.</Paragraph>
    <Paragraph position="1"> hal(H, license(pl6, p17)) \[linguistic\] Furthermore, the context here consists of a discussion of two tax years 1981 and 1982. Utterance (17) selects *ighLy one, with a narrow focus pitch accent. This implicates that there is some other tax year for which Joe is eligible, namely 198219\]. Joe's next utterance, but I am for 82, reinforces the implicature that Harry makes in (17), and upgrades the evidence underlying the assumption that (17) licenses (18) to linguistic.</Paragraph>
    <Paragraph position="2"> ACIES DE COLING-92, NANTES, 23-28 AO~r 1992 3 4 8 PROC. OF COLING-92, NANTES, AUG. 23-28, 1992</Paragraph>
    <Section position="1" start_page="0" end_page="0" type="sub_section">
      <SectionTitle>
4.1 Supporting Inferences
</SectionTitle>
      <Paragraph position="0"> A subcase of ensuring that certain inferences get made involves the juxtaposition of two propositions. These cases challenge the assumption that: (4) The context of a discourse is an undifferentiated set of propositions with no specific relations between them. While this assumption is certainly not made in most discourse models, it is often made in semantic models of the context\[14\]. In the following segment, Jane (j) describes her financial situation to Iiarry (h) and a choice between a setthment and an annuity.</Paragraph>
      <Paragraph position="1">  Example %: (l) j. hello harry, my name is jane (2:) h. welcome jane (3) j. i just retired december first, and in addition to my pension and social security, I have a supplemental annuity (4) h. yes (5) j. which i contributed to while i was employed (8) h. right (7) j. from the state of IJ mutual fund.  and ISm entitled to a lump sum settlement which would be betueen i6,800 and 17,800, or a lesser life annuity, and the choices of the annuity um would be $128.45 per month.</Paragraph>
      <Paragraph position="2"> That would be the maximum with no beneficiaries  (8) h. You can stop right there: take your money.</Paragraph>
      <Paragraph position="3"> (9) j. take the money.</Paragraph>
      <Paragraph position="4"> (10) h. absolutely.</Paragraph>
    </Section>
  </Section>
  <Section position="6" start_page="0" end_page="0" type="metho">
    <SectionTitle>
YOU'RE ONLY GETTING 1500 A YEAR.
</SectionTitle>
    <Paragraph position="0"> at 17,000, no trouble at all ~o get 10 percent on 17,000 bucks.</Paragraph>
    <Paragraph position="1"> Iiarry interrupts her at (8) since he believes he has enough information to suggest a course of action, and tells her lake ~lonr money. To provide SUPPORT for this course of action he produces an inference that follows from what she has told him in (7), namely You're only gelling 1500 (dollars) a year. SUPPORT is a general relation that holds between beliefs and intentions in this model.</Paragraph>
    <Paragraph position="2"> Presumably Jane would have no trouble calculating that $125.45 a month for 12 months amounts to a little over $1500 a year, and thus can easily accept this statement that is intended to provide the necessary SUPPORT relation, ie. the juxtapt~ition of this fact against the advice to lake the money conveys that the fact that she is only getting 1500 dollars a year is a reason for her to adopt the goal of taking the money, although this is not explicitly stated.</Paragraph>
  </Section>
  <Section position="7" start_page="0" end_page="0" type="metho">
    <SectionTitle>
5 Evidence of Acceptance
</SectionTitle>
    <Paragraph position="0"> In section 3, I examine the assumption that: (2) Propositions representing beliefs and intentions get added to the context by the unilateral action of one conversant.</Paragraph>
    <Paragraph position="1"> I suggested that this assumption can be replaced by adopting a model in which agents' behavior provides evidence for whether or not mutual understanding has been achieved. I also discussed some of the effects of resource bounds, is. eases of ensuring that or providing evidence that certain inferences dependent on what is said are made.</Paragraph>
    <Paragraph position="2"> Achieving understanding and compensating for resource bounds are issues for a model of dialogue whether or not agents are autonomous. But agents' autonomy means there are a number of other reasons why A's utterance to B conveying a proposition p might not achieve its intended effect: (1) p may not cohere with B's beliefs, (2) B may not think that p is relevant, (3) B may believe that p does not contribute to the common goal, (4) B may prefer doing or believing some q where p is mutually exclusive with q, (5) If p is about an action, B may want to partially modify p with additional constraints about how, or when p, Therefore it is important to distinguish an agent actually ACCEPTING the belief that p or intending to perform an action described by p from merely understanding that p was conveyed. Other accounts legislate that helpful agents should adopt other's beliefs and intentions or that acceptance depends on whether or not the agent previously believed ~ Pill, 8\]. But agents can decide whether as well as how to revise their beliefs\[4\]. Evidence of acceptance may be given explicitly, but acceptance can be inferred in sonm dialogue situations via the operation of a simple principle of cooperative dialogueS:</Paragraph>
  </Section>
  <Section position="8" start_page="0" end_page="0" type="metho">
    <SectionTitle>
COLLABORATIVE PRINCIPLE: Conversants
</SectionTitle>
    <Paragraph position="0"> must provide evidence of a detected discrepancy in belief as soon as possible.</Paragraph>
    <Paragraph position="1"> This principle claims that evidence of conflict should be made apparent in order to keep default inferences about acceptance or understanding from going through. 1RU's such as PROMPTSp REPETITIONS~ PARAP|IRASES, and making an INFERENCE explicit cannot function as evidence for conflicts in beliefs or intentions via their propositional content since they are informationally redundant. If they are realized with question intonation, the inference of acceptance is blocked.</Paragraph>
    <Paragraph position="2"> In the dialogue below between tiarry (b) and Ruth (r), Ruth in (39), first ensures that she understood Harry correctly, and then provides explicit evidence of non-acceptance in (41), based on her autonomous preferences about how her money is invested..</Paragraph>
    <Paragraph position="3"> STiffs is a simplification of the COLLABOnATIVE PLANNING PRINC~PLE~ described in \[15\].</Paragraph>
    <Paragraph position="4"> Ac'rEs DE COLING-92, NANTES, 23-28 Ao~-r 1992 3 4 9 PROC. OF COLING-92, NANTES, AUG. 23-28. 1992 Exa~le 5 :  (38) h. and I'd like 1K thouwand in a 2 and a half year certificate (39) r. the full 18 in a 2 and a half? (40) h. that's correct (41) r. GEE. NOT AT MY AGE  In the following example, Joe in (14) makes a statement that provides propositional content that conflicts with Harry's statement in (13) and thus provides evidence of non-acceptance.</Paragraph>
    <Paragraph position="5"> Exmaple 6  (13) h. and -- there's no reason why you shouldn'~ have an I It h for last year (14) j. WELL I THOUGHT TSEY JUST STPSRTED</Paragraph>
  </Section>
  <Section position="9" start_page="0" end_page="0" type="metho">
    <SectionTitle>
THIS YEaR
</SectionTitle>
    <Paragraph position="0"> Joe's statement is based on his prior beliefs. In both of these cases this evidence for conflict is given immediately. However when there is no evidence to the contrary s, and goals of the discourse require achievement of acceptance, inferences about acceptance are licensed as default. They can he defeated later by stronger evidence.</Paragraph>
    <Paragraph position="1"> Without this principle, a conversant might not bring up an objection until much later in the conversation, at which point the relevant belief and some inferences following from that belief will have been added to the common ground as dtafanlts. The result of this is that the retraction of that belief results in many beliefs being revised. The operation of this principle helps conversants avoid replanning resulting from inconsistency in beliefs, and thus provides a way to manage the augmentation of the common ground efficiently.</Paragraph>
  </Section>
  <Section position="10" start_page="0" end_page="0" type="metho">
    <SectionTitle>
6 Other hypotheses
</SectionTitle>
    <Paragraph position="0"> The first point to note is that the examples here are only a subset of the types of IRU's that occur in dialogues. I use the term antecedent to refer to the most recent utterance which should have added the proposition to the context. This paper has mainly focused on cases where the IRU: (1) is adjacent to its antecedent, rather than remote; (2) realizes a proposition whose antecedent was said by another conversant, (3) has only one antecedent. It is with respect to this subset of the data that the alternate hypotheses are examined.</Paragraph>
    <Paragraph position="1"> A distributional analysis of a subBet of the corpus (171 IKU's from 24 dialogues consisting of 976 turns), on the relation of an IRU to its antecedent and the context, shows that 35% of the tokens occur remotely from their antecedents, that 32% have more than one antecedent, that 480PS consist of the speaker repeating something that he said before and 52% consist of the speaker repeating something that the other conversant said. So sThls displaying of evidence to the contrary was called sat interruption in \[15\].</Paragraph>
    <Paragraph position="2"> the data that this paper focuses on accounts for about 30% of the data.</Paragraph>
    <Section position="1" start_page="0" end_page="0" type="sub_section">
      <SectionTitle>
6.1 Indirect Question Hypothesis
</SectionTitle>
      <Paragraph position="0"> In example (1) of section 1, an alternative account of Ray's repetition in (8) is that it is a question of some kind. This raises a number of issues: (i) Why doesn't it have the form of a question?, (2) What is it a question about?, and (3) Why is it never denied?.</Paragraph>
      <Paragraph position="1"> Of 171 IRU's, only 28 are realized with rising question intonation. Of these 28, 6 are actually redundant questions with question syntax, and 14 are followed by affirmations.</Paragraph>
      <Paragraph position="2"> If these are generally questions, then one possible answer to what the question is about is that Ray is questioning whether he actually heard properly. But then why doesn't he use an intonational contour that conveys this fact as Ruth does in example 5? On an efficiency argument, it is hard to imagine that it would have cost Ray any more effort to have done so.</Paragraph>
      <Paragraph position="3"> Finally, if it were a question it would seem that it should have more than one answer. While 50 of these IRU's are followed by an affirmation such as that's cot.</Paragraph>
      <Paragraph position="4"> reef, right, yup, none of them are ever followed by a denial of their content. It seems an odd question that only has one answer.</Paragraph>
    </Section>
    <Section position="2" start_page="0" end_page="0" type="sub_section">
      <SectionTitle>
6.2 Dead Air Hypothesis
</SectionTitle>
      <Paragraph position="0"> Another hypothesis is that IRU's result from the radio talk show environment in which silence is not tolerated.</Paragraph>
      <Paragraph position="1"> So agents produce IRg's because they cannot think of anything else to say but feel as though they must say something.</Paragraph>
      <Paragraph position="2"> The first point to note is that IRU's actually occur in dialogues timt aren't on the radio\[l\]. The second question is why an agent would produce an IRU, rather than some other trivial statement such as I didn't know thai. Third, why don't these utterance correlate with typical stalling behavior such as false starts, pauses, and filled pauses such as uhhh.</Paragraph>
      <Paragraph position="3"> The dead air hypothesis would seem to rely on an assumption that at unpredictable intervals, agents just can't think very well. My claim is that IRU's are related to goals, that they support inferencing and address assumptions underlying mutual beliefs, is. they are not random. In order to prove this it must be possible to test the hypothesis that it is only important propositions that get repeated, paraphrased or made explicit. This can be based on analyzing when the information that is repeated has been specifically requested, such as in the caller's opening question or by a request for information from Harry. It should also be possible to test whether the IRU realizes a proposition that plays a role in the final plan that Harry and the caller negotiate. However this type of strong evidence AcIxs DE COLING-92, NANTES, 23-28 Aour 1992 3 5 0 PROC. OF COLING-92, NANTES, AUG. 23-28, 1992 against the dead air hypothesis is left to future work.</Paragraph>
    </Section>
  </Section>
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