<?xml version="1.0" standalone="yes"?>
<Paper uid="W99-0102">
  <Title>e O O O O O O O O 0 O O @ O O 0 O O O O O O O O O O O 0 O O O @ O O O O @ O O O Approachesto Japanese zero pronouns: Centering and relevance</Title>
  <Section position="3" start_page="12" end_page="16" type="metho">
    <SectionTitle>
OBJECT&gt; OTHERS
</SectionTitle>
    <Paragraph position="0"> As you can see, they add two new grammatical roles, namely, topic and empathy, to the list of factors affecting pronoun resolution. Since the notion of topic will become important in the discussion which follows, I will briefly describe the Japanese topic marker below. For empathy-loaded verbs, please refer to Kuno 1987 and Kuno &amp; Kaburaki 1977.</Paragraph>
    <Paragraph position="1"> In Japanese, both in written and spoken discourse, lqPs which can be recovered from context are often omitted. The omitted NPs are often called 'zero pronouns'. It is widely agreed that missing NPs in JapaneSe behave like pronouns in other languages such as There were only three aTtn:idon statea in t&amp;e origml  \[o~ulmion by Gron et ~ (1983, /99S), namely, CONTINUE, RETAIN and SHIFZ. Fhe distinction between SMOOTH-SHIFT and ROUGII-SHIFF w~r \[u~ proposed in Brenn~ (1987).</Paragraph>
    <Paragraph position="2">  English. Japanese zero pronouns should be distinguished from missing NPs in 'pro-drop' languages such as Italian, since in 'pro-drop' languages, information to recover missing NPs is morphologically encoded elsewhere in the sentence, e.g. in the form of verb inflection, whereas Japanese lacks such an overt encoding.</Paragraph>
    <Paragraph position="3"> Japanese zero pronouns are used equally often as inter-sentential discourse anaphors and intra-sentential anaphors. Here, I will concentrate on their use as discourse anaphors, where the role of context and adequate pragmatic criterion is crucial. For those who are interested in intra-sentential use of zero pronouns, please refer to e.g. Hasegawa 1985 and Kameyama 1986.</Paragraph>
    <Paragraph position="4"> In Japanese, there are several postpositional particles. The one we are interested in here is 'wa; which is often called a ~opic marker: As the name suggests, 'via' is typically used to construct a grammatical topic of a sentence, which is characterised as an entity whose existence is presupposed. The function of 'wa&amp;quot; might become clearer when it is compared with another particle 'ga; which marks a hrP in the subject position, which typically conveys a new information. Compare (6a) and (6b):  (6) a. John ga hana o kaua.</Paragraph>
    <Paragraph position="5"> SUB flowers ACe bought * 'John bought flowers.' b. John wa hana o katta.</Paragraph>
    <Paragraph position="6"> TOP flowers A~ bought &amp;quot;John bought flowers.' (6a) and (6b) share the same propositional  content. However, only (6a) is acceptable as an answer to the question such as Who bought flowers?&amp;quot; while only (6b) is acceptable as an answer to the question such as What did John buy?'. There are various suggestions about how to characterise functions of the two particles (see e.g. Shibatani 1990; Tanaka 1991), and although it is an interesting question on its own, it shouldn't concern us here. This is because Walker et al. are only interested in the surface form of 'lqP+wa;  which is automatically given the highest accessibility ranking in their framework.</Paragraph>
    <Paragraph position="7"> Walker et al. claim that a topic NP is more likely to be realised as a zero pronoun in the subsequent discourse than any other NPs due to its highest degree of accessibility.</Paragraph>
    <Paragraph position="8"> Moreover, in Walker et al. 's framework, topic NP is given two further advantages: they suggest (a) that a NP marked by %va' becomes the backward-looking center even at the onset of the discourse; and (b) that once topic NP is realised as the backward-looking center ,as long as it continues to be realised as a zero pronoun in subsequent discourse, it could continue to be the backward-looking center. The second advantage given to the topic NP is called 'zero topic assignment', which is defined as in (7):</Paragraph>
    <Paragraph position="10"> When a zero in Ui+l representsan entity that was Cb (Ui), and when no other CONTHqUE transition is available, that zero may be interpreted as the ZERO TOPIC of Ui+l Walker et al. demonstrate that their framework, including an optional rule of zero topic assignment, can successfully explain the preference in the interpretation of the last sentence in (8):  According to the questionnaire carried out by Walker et al., the preferred interpretation of \[4\] is that Hanako invited Michiko to lunch. As you can see, in fact, there are two possible ways of ranking forward-looking center in \[3\], and two possible ways of deciding both the backward-looking center and the ranking of forward-looking center in \[4\]. In their analysis of (8), the preference in the interpretation in \[4\] is explained by zero topic assignment in \[3\] and preference on 'continue' transition in \[4\].</Paragraph>
    <Paragraph position="11"> In summary, Walker et aL's account of Japanese zero pronoun is based on two independent preference mechanisms: the first one is the forward center farting, and the second is the ordered transition states.</Paragraph>
    <Paragraph position="12"> However, as Walker et al. themselves point out, each transition state between discourse segments is determined by the ordering of forward looking centers, the predictions of the theory tend to depend more largely on the forward center ranking.</Paragraph>
    <Paragraph position="13"> 3. Problems with Walker et al.</Paragraph>
    <Paragraph position="14"> Now I would like to discuss some problems With Walker et al. &amp;quot;s framework. Needless to say. it has great advantages, such as relative ease of computational imPlementation.</Paragraph>
    <Paragraph position="15"> Moreover, I agree that accessibility of  discourse entities plays an important role in reference assignment, and their forward center ranking is an adequate enough approximation of accessibility of discourse entities in different grammatical categories in Japanese. However, as I mentioned before, there are cases whose interpretation process cannot poss!bly be explained by the accessibility factor alone. Accounts of reference assignment which are largely based on accessibility of discourse entities tend to exhibit their weaknesses when they face cases which require some pragmatic inferences, and Walker et al. is not an exception here. I will illustrate two problems they need to solve below.</Paragraph>
    <Paragraph position="16"> 3.1, Multiple topics One of the most obvious shortcomings of Walker et al. 's approach is that it cannot handle situations where there is more than one topic in a sentence. In their framework, in order to identify zero pronouns, the backward-looking center has to be identified first. The backward-looking center, in turn, is determined by the way forw~d-looking centers are ranked. Therefore, the most powerful mechanism in their framework is the forward-looking center ranking shown in (5) above. However, notice that it is only useful if there is no more than one entity in each category in a sentence.</Paragraph>
    <Paragraph position="17"> Let us concentrate on the category of topic here. In Walker et al. 's framework, the topic marker 'wa' is given a special status: the topic marker 'wa' is so powerful that the topic NP becomes the most highly ranked forward-looking center even at the onset of a discourse; in addition, once a topic NIP is realised as the backward-looking center, as long as it continues to be realised as zero pronoun in subsequent discourse, it could continue to be the backward-looking center. This status of the topic NP rightly allows the possibility of multiple topics as in (9), which is very often seen in Japanese discourse: (9)\[1\] Mary to Jane war shinyuu ck and TOP best friends are 'Mary and Jane are each other's best.</Paragraph>
    <Paragraph position="18">  ohiru goro denwa shita.</Paragraph>
    <Paragraph position="19"> noon around telephone did 'As always, Jane phoned (Mary) around noon.</Paragraph>
    <Paragraph position="20"> \[4\]0 0 eiga ni so, sou tsurnori datta.</Paragraph>
    <Paragraph position="21"> film to invite planning to was '(She) was planning to invite (her) to a film.' However, cases of multiple topics cause a serious problem to Walker et al. Here, the preferred interpretation of \[4\] is that Jane was planning to invite Mary to a film. Walker et al. might explain this preference by saying that this is because 'Jane'is the backward-looking center in \[4\]. According to their framework, however, the alternative interpretation, namely, that Mary was planning to invite Jane to a film, is equally accessible, since 1Vfary&amp;quot; could continue to be the backward-looking center in \[4\]. The problem is that in their current framework, Walker et al. do not provide any mechanism to choose one interpretation and discard the other.</Paragraph>
    <Paragraph position="22"> There is another problem concerning multiplicity of entities with equal degree of accessibility. In Japanese, post-positional particles such as ~va' and 'ga&amp;quot; shouldn't be used more than once in a sentence. Thus, you wouldn't come across sentences with two overtly marked topics or subjects. However, it is possible to have more than one NP with more or less equal salience in one sentence, for example, when two nouns; the first being a modifier and the second being the head noun, form a NP. A noun modifier is followed by a particle 'no', the Genitive Case particle. Some examples of NPs which contain noun modifiers are shown in (10):  (lO)a. Mary no tomodachi GEN friend qVIary's friend' b. Niwa no ki garden GEN tree 'A tree in the garden&amp;quot; c. Tegami no henji letter GEN reply  'A reply to the letter' Here, the first noun in each NP is the modifier. The most typical relation exhibited between two nouns combined by the particle 'no' is the 'possessive' relation, as in (lOa). However, the use of 'no' is by no means restricted to that relation, as illustrated in (lOb) and (lOc). Now consider (11), which include a NP with this structure: ( i I)(A memo written by a man, and addressed to his wife) \[l\]Kooto no botanga toreta.</Paragraph>
    <Paragraph position="23"> ', coat GEN button SUB came off ~3ne of the buttons of (my) coat has  ( 12)\[1\]Sakuba~ John wa fitensha no kagi last night TOP bicycle GEN key o kake-wasweta.</Paragraph>
    <Paragraph position="24"> ACe lock-forget  l.ast night, John forgot&amp;quot; to use the key to lock his bicycle' \[2\]gesa, too, 0 na/amatteita.</Paragraph>
    <Paragraph position="25"> this morning already gone-has This morning, (it) has already gone' In (11), 'one of the buttons of my coat' is introduced in \[1\] as the subject of the sentence. What is important here is that the NP introduces two conceptual entities, namely, a 'coat' and a ~outton', which are equally accessible. The question is whether Walker et al. 's framework can handle cases like (11). For \[2\], the preferred interpretation is that the speaker wants his wife to find and fix the button today. Walker et al. 's system would successfully predict that the button is the backward-center+ for \[2\] and \[3\]. However, for \[4\], the preferred interpretation is that the speaker will need his coat tomorrow, rather than the button. I do not see how Walker et al. can explain this. Example (12) causes exactly the same problem for them. Walker et al. would predict that the preferred interpretation should be that the key has gone. This obviously is the wrong prediction. The point I would like to make here is that there are many cases in Japanese discourse where there is more than one roughly equally salient discourse entity in a sentence which subsequently become equally strong candidate referents for zero pronouns, and some mechanism of choosing the right one is needed.</Paragraph>
    <Paragraph position="26"> 3.2. Ordered preference of transition states Now I would like to move on to a different kind of problem, which concerns their ordered preference of transition states shown in (4). Walker et al., as well as centering theorists in general, assume that when there are more than one possible overall interpretation available, the one which exhibits 'continue' transition is prefene&amp; This is based, on the assumption that maximally coherent segments are those that require less processing effort and the heater will prefer an interpretation which requires less processing effort. However, it is not difficult to think of examples which go against their assumption. For example, look at (13) and (14):</Paragraph>
    <Paragraph position="28"> (i.e. John cannot help feeling ashamed of himself in front of his boss).</Paragraph>
    <Paragraph position="29"> \[2\]ltsumo 0 kaisha ni 0 saki ni kuru.</Paragraph>
    <Paragraph position="30"> always office to earlier come '(He) always comes to the office earlier  (than him).' a. (John) always comes to the office earlier (than his boss).</Paragraph>
    <Paragraph position="31"> b. (John's boss) always comes to the office than (John).</Paragraph>
    <Paragraph position="32">  Let us look at (13) first. What interests me here is the interpretation of the zero pronoun in \[3\]. Notice that both \[3a\] and \[3b\] are equally acceptable in terms of factual plausibility. In such case, Walker et al, would predic~ that \[3a\], which exhibits a 'continue' transition should be preferred. However, for some reason, the preferred interpretation for \[3\] is not \[3a\], but \[3b\]. Similarly, in (14), the preferred interpretation for \[21 is definitely \[2b\]. However, Walker et al. predict that \[2a\] should be preferred. Obviously, their mechanism based on the accessibility of transition states makes wrong predictions. In the next section, I will consider why this is the case.</Paragraph>
  </Section>
  <Section position="4" start_page="16" end_page="19" type="metho">
    <SectionTitle>
4. A relevance-theoretic solution to
</SectionTitle>
    <Paragraph position="0"> preblems with Walker et al.</Paragraph>
    <Paragraph position="1"> Sperber &amp; Wilson's relevance theory (Sperber &amp; Wilson 1986/95) inherits the Gricean assumption that the hearer's goal of verbal  understanciing is to find an interpretation intended by the speaker. However, it differs from Gricean approach in two crucial points: it does not take the view that we have to follow maxims, nor the view that we have to be cooperative, to achieve successful communication. Sperber &amp; Wilson claim that what makes communication achievable at all is a fundamental mechanism built in our cognitive system, namely, the pursuit of relevance. This is expressed as the First, or  maximisation of relevance.</Paragraph>
    <Paragraph position="2"> the .The notion of relevance is defined in terms cognitive effects, i.e. some changes in the belief system, and processing effort to obtain such effects: (16)Relevance a. The greater the cognitive effects, the greater the relevance; b. The smaller the effort needed to achieve those effects, the greater the relevance. Cognitive effects result from the interaction of new and old (or contextual) information in one of the following three ways: (a) combining wi.~..~ an existing assumption to yield contextual implications; (b) strengthening an existing assumption; (c) contradicting and eliminating an existing assumption.&amp;quot; Processing effort is the mental effort needed to parse the utterance, decide what proposition and propositional attitude it was intended to express, access an appropriate context, and work out the contextual effects of the utterance in the context. When an utterance has more than one possible interpretation, the hearer should look for the one which satisfies the following conditions of optimal relevance: ( 17)Optimal relevance An utterance is optimally relevant to the heater iff: a. it is relevant enough to be worth the heater's processing effort; b. it is the most relevant one compatible with the speaker's abilities and preferences. The Second, or Communicative Principle of Relevance, governs this search process: (I 8)Communicative Principle of Relevance Every utterance communicates a presumption of its own optimal relevance.</Paragraph>
    <Paragraph position="3"> The pursuit of optimally relevant interpretation suggests a pattern of comprehension procedure the hearer should follow, which can be spelled out as (19): (19)Relevance-theoretic comprehension procedure a. consider cognitive effects in their order of accessibility (i.e. follow a path of least effort); b. stop when the expected level of relevance is achieved.</Paragraph>
    <Paragraph position="4"> Now let me illustrate how this comprehension procedure should work for Japanese zero pronoun resolution illustrated in (11), (12), (13) and (14). In Matsui (1995, 1998, also Wilson and Matsui 1998), I have developed the idea proposed by Wilson (1992) that in addition to the factor of accessibifity of candidate referents, there is another important factor which affects the bearer's choice of referent, namely, accessibifity of contextual assumptions. Accessibility of contextual assumptions becomes particularly crucial when there is more than one roughly equally accessible candidate referent. and it is the factor which is vital to solve problems with Walker et al.. In fact. the importance of contextual assumptions in reference resolution had been recognised before and various proposals were made as to how to retrieve the right context: some appeal to situationally partitioned knowledge (e.g. Sanford &amp; Oan~ 1981) and others arc motivated by textual coherence (e.g. Hobbs 1979; Asher &amp; Lascarides 1993). The account pursued here is different from any existing accounts in that it  claims that the selection of contextual assumptions is ordered in terms of both their accessibility and likeliness to contribute towards cognitive effects of the utterance. In other words, in relevance theory, it is assumed that these candidate referents are tested in parallel, with the one which gives quickest access to a context in which the utterance as a whole yields an acceptable overall interpretation being selected.</Paragraph>
    <Paragraph position="5"> As a working hypothesis, let us assume that certain contextual assumptions are accessed by the hearer after the immediately preceding utterance is processed, during and after the current utterance is being processed. I have no specific claim here concerning what triggers the retrieval or the construction of certain contextual assumptions, and can go along with existing suggestions (e.g. it can be triggered by lexical information, or/and by situational knowledge). As the second working hypothesis, I would like to suggest that after having understood an utterance, the hearer tends to have, if not always, fairly accurate expectation as to what kind of cognitive effects he would like to obtain from the next utterance.. Relevance theory predicts that when an utterance creates in the hearer an expectation for a specific cognitive effect to be achieved by the next utterance, other things being equal, the hearer is more likely to spen d his processing effort to find an interpretation which can achieve such cognitive effect when interpreting the utterance. As a consequence, the candidate referent which is not the highest in the general accessibility ranking can become the most accessible to the hearer if the referent is expected to contribute to the interpretation hc is looking for. In other words, relevance theory predicts the alteration of accessibility ranking of the candidate referents as a result of the pursuit of certain cognitive effects.</Paragraph>
    <Paragraph position="6"> Consider examples (I1) and (12) in the context discussed above. In (11), the utterance in \[3\] is a request to the wife to find and fix the missing button of the speaker's coat before tomorrow. Generally, if someone asks you to do something by certain time, there should be  a good reason for such a time limit, since the time limit in turn maY create certain priority. Thus, it should be reasonable to assume that after hearing the utterance in \[3\], the question such as 'why do I have to do it today?' or 'can't it wait a little while?' occurred in the hearer's mind. If so, the utterance in \[4\] can readily be interpreted as the reason why he made such a request: he wants to wear the coat on the following day. The referent is assigned automatically during the process of finding expected the cognitive effects. Of course, what he needs is the coat with the button fixed, and this interpretation is only possible with the overall interpretation in which the 'coat: rather than the 'button&amp;quot; is the referent of the zero pronoun. The first utterance in (12), on the other hand, seems to create different kind of expectation in the hearer. After hearing that the bicycle was left unlocked, the most likely question occurs to everyone's mind is 'what happened to the bicycle?&amp;quot; We all know the likely consequence of the unlocked bicycle, and the hearer of (12) gets the expected contextual effects by interpreting the zero pronoun as the ~icycle; rather than the ~ey '. In both (13) and (14); it is reasonably assumed that the hearer will have a why-question in his mind before hearing the final utterance. In the case of (13), the only possible reason why John could not confirm the time with Peter by phone was because Peter was not .at home when John phoned, and the zero pronoun is resolved .automatically in the process of obtaining this interpretation. I will Jook at (14) in more detaiL The interpretation of (14) might be explained like this. After processing the first utterance, certain assumptions might become moderately accessible (but not necessarily at the conscious level) to the hearer:, e.g. various assumptions about John and his boss, and more general assumptions about l~eing ashamed of; e.g.</Paragraph>
    <Paragraph position="7"> that one must feel unhappy about such situation, or that one must have specific reasons for such feeling, etc. In this way, contextual assumptions might contribute to form the hearer's anticipation about the way subsequent utterances achieve relevance.</Paragraph>
    <Paragraph position="8"> When the hearer interprets the second utterance in (14), further:-assumptions related to the event described, such as that 'workers are encouraged to come to work early ', or ~osses like their workers to arrive before them' etc., might become highly accessible.</Paragraph>
    <Paragraph position="9"> Such assumptions contribute to the hearer's search for the way the utterance could achieve cognitive effects. At the final stage of the interpretation process, the hearer finds the only way in which the second utterance in (14) might be intended to achieve relevance in a context created by the first - namely, as an explanation for why John cannot help feeling ashamed of himself in front of his boss - and the zero-pronouns are resolved automatically in the process.</Paragraph>
    <Paragraph position="10"> Furthermore, notice that as a consequence of using the notion of accessibility of contextual assumptions, an ad hoc system such as the ordered preference in transition states in Walker et aL's account becomes automatically unnecessary. For example, our framework could easily accommodate cases such as (13) and (14), where the referent of a zero pronoun in the current discourse is not the same as that of a zero pronoun in the preceding discourse, as well as cases where the most accessible candidate referent indeed coincides with the referent chosen on the basis of the preferred overall interpretation. Recall that the ordered transition states is created on the basis of the assumption that the hearer prefers an interpretation which exhibits 'continue&amp;quot; relation, because such an interpretation requires less processing effort. I suggest that this assumption is ultimately wrong for the following reason: the preferred interpretation by the hearer is the one which provides enough cognitive effects worth his processing effort, rather than the one which merely requires less processing effort. Walker et al. would predict that the preferred interpretation for the second sentence in (14) is that &amp;quot;John always comes to his office earfier than his boss.' The question we have to ask here is: how could this interpretation possibly achieve relevance? I cannot easily see how. Relevance theory predicts that such interpretation will  never be considered when there is an alternative interpretation accessible which achieves relevance, even if the latter might require more processing effort. Notice here that the relevance theory shares the view that the intended interpretation should be the most accessible one for the hearer. However, in the framework of relevance theory, it is accessibility of contextual assumptions, together with the accessibility of contextual referents, that determines the overall accessibility of an interpretatimL In this way, the fact that the preferred interpretation of the second sentence in (14) is more accessible overall for most of us, than the alternative interpretation, is adequately explained in this framework.</Paragraph>
  </Section>
  <Section position="5" start_page="19" end_page="19" type="metho">
    <SectionTitle>
5. Summary
</SectionTitle>
    <Paragraph position="0"> In this paper, I have proposed a way of complementing centering theory from a relevance-theoretic perspective. I have suggested that a model of reference assignment which appeals to the expectation based on the accessibility of candidate referents such as centering theory should ultimately accommodate some mechanism of contextual selection and pointed out that the hearer's expectation of specific contextual effects (a type of forward inferences) should be taken advantage of in creating such a mechanism. Recently, Oberlander (1998) says that 'the key lesson from the work on pronoun generation and interpretation is that we must develop a more sophisticated view of '~xpectafion.&amp;quot;I hope this paper makes some contribution towards that goal.</Paragraph>
  </Section>
class="xml-element"></Paper>