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<Paper uid="C88-1044">
  <Title>On the Generation and Interpretation of Demonstrative Expressions*</Title>
  <Section position="4" start_page="216" end_page="216" type="intro">
    <SectionTitle>
3. CONSTRAINTS ON DEMONSTRATIVE USE
</SectionTitle>
    <Paragraph position="0"> The basic concepts which we take to be crUcial for any adequate description of demonstxatives are ones which are central to a theory of reference in general. These are concepts such as topic, focus and various types of givenness. Since these concepts concern the cognitive status of a referent, definitions have often been iough and iatuitive, bv.:dcatiy con'ect but ~tot sufflcieLitly precise for eonlput~;ikmal iulplcmctmttion. On the oilier hand, because of the conlpledty of these concepts, attempts to ihrnish ntore precise opcrallonal definitions, e.g. on the basis of surlhce line.'n of dcr or gLm,L matical rclatiot~s~ have failed to capture lhcir cognitive basis. 'lh(; ccsult has heel, a icrminological and conceptual cort-Nsion ill tl~C literature which has led computational linguists to create nc.w t:onsh;ucts such as fc)cns arid center, in some cases without rcl:tting tllc;m to similar linguistic concepts (Itajicov:t 1987 is an, ltablc exception). Our aim hcrc is t-L characterize as p~vcisely as possible what the relevant concepts for deruouslraiives arc :.hid how they relate to one anoihcr. In a later section wc will attcnlpt tl~ show how they Lelate to more operational constructs prop 3sed in the, computational literature.</Paragraph>
    <Paragraph position="1"> Defiuit~.'ne~So As has often been pointed out, the basic notion which dctcrntines ~q)prol)riateness of a given rcfi.:rential cxpres.</Paragraph>
    <Paragraph position="2"> sion is the; status of the refcrc,t of lhat expression vis.a-vis a cognitive. :;tale of the addressee (cf. Chafe 19'/6). hi the weakest c~\:;t:, the SFeakcr c:~\[Lt:~.is the itddtcssee to uffdcrstand what type of eniily is beittg described, but not to uniquely identify the entity in q/,cslion. Such c,~ities arc typically reiEl'cnccd with indefinite itotni pbra!;cs The nlost basic distinction in demonstrative \[tntciion i~; between tile indefinite use of lhe determiner 1his, as ~:xemplified in (t) and all other uses of hoth determiner and prouomiflal denlonstratives, which arc definite. As has bccll pointed ot,~ by a number of researchers, indcfinite this occurs only in cat;~,al, n,@a,ncd discouLsc. Tilts obscrvalion was con-.</Paragraph>
    <Paragraph position="3"> firmed hy our own study, which found instances of indefinite this ot,ly in the inhlrmal coaversalkms.</Paragraph>
    <Paragraph position="4"> (1) i couldn't sleep last night. My neighbors have this dog that kept me awake.</Paragraph>
    <Paragraph position="5"> We will be primarily concerned hete with definite noun phrases, where the speaker expects the addressee to uniquely identify the mlin'cnt on tile basis of the description in question.</Paragraph>
    <Paragraph position="6"> Th,e rcfe,e~lts of such expressions have often been characterized as 'given'. tlowevcr, as pointed out by Gundcl (1978a, 1978b) and l'rince (1981h), givcnness is not a mfitary concept. There arc diil'ereat senses of givenness each of which is relevant to the Rn'm of reicc,'ittg expr,-ssions, but in different ways.</Paragraph>
    <Paragraph position="7"> hletttiliabitity. In the weakest sense of givcnness, the slmaker expects the addressee to uniquely identify the referent, but the basis for th: identification is iiTelevant. Not only can it be linguistic or extralingttistic, based on entities in immediate or long term memory, but it need not he based on any previous shared experience ;:it all (cf. lIawkins 1978). The basis/'or the identification may be enc~led in lhe form itselt, as in (2).</Paragraph>
    <Paragraph position="8"> (2) I couldn't sleep last night. The neigltboes dog kept me awake.</Paragraph>
    <Paragraph position="9"> This type of givenness, which we rctisr to as identitiability, is both necessary and Slffficient tot the use of deliniie articles.</Paragraph>
    <Paragraph position="10"> Shared t'alailiarity. Most identifiable entities are identifiable because of some shared experience between speaker and aft.</Paragraph>
    <Paragraph position="11"> dressec; again this may be linguistic or exlralinguistic, based on local colRext or hmg term menuLly associated with shared cultural or personal expt:rienct:. It is tiffs slattls which we claint is necessary for the use of demonstrative expressions (with the exception of indcfinit,~ this ). Thus, (3) unlike (2), is li:licitous only if the addressee has prior knowledge of the dog in question.</Paragraph>
    <Paragraph position="12"> (3) I couldn't sleep last night. That dog next door kept me awake.</Paragraph>
    <Paragraph position="13"> ActilzatioJii. Entities which are fantiliar on the basis of presence in the imnlcdiate discourse context (either linguistic or extralingnistic) are not only shared but 'in awareness.' This sense of pjvcmless, which wc reler to as 'activated,' (of. Chafe 1976, Gundel 1978b, Haji~fov;i and Vrbovfi 1982) is necessary tor pronominal reference, including pronominal demonstratives.</Paragraph>
    <Paragraph position="14"> Thus, that' in (4) could only r~:li:r to the bmkiog of a dog if this \[lad lrg;eu ac~ivaR;d b) r the hnnu-diatc discourse context: (4) 1 couldn't sleep last night. That kept me awake.</Paragraph>
    <Paragraph position="15"> Activation is also a necessary condition for determiner this.</Paragraph>
    <Paragraph position="16"> Demonstcative this, both pronominal and definite determiner, has the additional condition that it not only be activated but speaker- null activated, either linguistically or extralinguistically by virtue of its inclusion in the speakers context space, as in (5): (5) A: Have you seen the neighbors new dog? B: Yes, and that dog kept me awake all night.</Paragraph>
    <Paragraph position="17"> B': ??Yes, and this dog kept me awake all night.</Paragraph>
    <Paragraph position="18">  \[r~ focus. Finally, the most highly activated entities are not only in the speaker's arid ltearer's awareness but are the center of attention at ;t particular point in the discourse. We refer to this status as 'in focus.' Entities in .focus 1 always include at least the topic of the sentence as well as any higher level discourse topics which may not be overtly represented in the sentence itself. Under certain conditions, they may also include other elements such as the reference of the linguistic focus. Thus a shift in focus always entails a shift in topic but not vice versa. The status 'in tootis' is a necessary condition for unstressed pronomlnals and also for zero anaphora (cf. Gundel 1978b).</Paragraph>
    <Paragraph position="19"> The rehtlionship between tile various (definite) referential statuses and the forms that colTelate with them is shown in (6).</Paragraph>
    <Paragraph position="20"> These statuses are in a unidirectional implication rclation such that any status on lhe hierarchy implies all statuses higher on the hierurchy but not vice-.versa:</Paragraph>
  </Section>
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