# Abstracts of HCRC Research papers, 1992

Anne H. Anderson, Aileen Clark and James Mullin:
Communication Skills in Children: Learning how to Make Language Work in Dialogue
In this paper we investigate the development of interactive communication skills in 170 children aged from 7--13. Using a communication task that allows extended dialogues between pairs of young speakers, we are able to assess both the overall communicative success achieved by any pair and from analysing the dialogues we can identify several interactive strategies that characterize older and more successful communicators. Successful communication involves the active involvement of both participants, asking and answering questions, volunteering information and responding sensitively to contributions from their partners. In contrast to the process of language acquisition, the development of these interactive askills takes place over an extended time period and subjects vary greatly in thr ability to communicate effectively. For many analyses the effects of communicative skill are more strking than those of age. For example, a substantial minority of our oldest subjects communicate no better than children 6 years younger.
(March 1992; 27 pages)
Ref. No: HCRC/RP-27 Price: UKL 1.20

Keith Stenning and Mike Oaksford:
Rational Reasoning and Human Implementations of Logic
In this paper we draw some general conclusions about the relation between logic and the analysis of human reasoning; that relation is illumninated by considerations of implementation. We conclude that a modern view of logic which is much more abstract than earlier views makes a good partner for psychology because it focusses attention on issues about how fragments of logics can be implemented within known resource limitations, and these are the foremost issues with which a psychology of reasoning should concern itself.
(March 1992; 40 pages)
Ref. No: HCRC/RP-28 Price: UKL 1.50

Anne H. Anderson, Miles Bader, Ellen Gurman Bard, Elizabeth Boyle, Gwyneth Docherty, Simon Garrod, Stephen Isard, Jacqueline Kowtko, Jan McAllister, Jim Miller, Catherine Sotillo, Henry Thompson and Regina Weinert:
This paper describes a corpus of unscripted, task-oriented dialogues which has been designed, digitally recorded, and transcribed to support the study of spontaneous speech on many levels. The corpus uses the Map Task (Brown, Anderson, Yule, and Shillcock, 1983) in which speakers must collaborate verbally to reproduce on one participant's map a route printed on the other's. In all, the corpus includes four conversations from each of 64 young adults and manipulates the following variables: familiarity of speakers, eye contact between speakers, matching between landmarks on the participants' maps, opportunities for contrastive stress, and phonological characteristics of landmark names. The motivations for the design are set out and basic corpus statistics are presented.
(March 1992; 22 pages)
Ref. No: HCRC/RP-29 Price: UKL 1.10

Fairouz Kamareddine and Ewan Klein:
Nominalization, Predication and Type Containment
In an attempt to accommodate natural language phenomena involving nominalization and self-application, various researchers in formal semantics have proposed abandoning the hierarchical type system which Montague inherited from Russell, in favour of more flexible type regimes. We briefly review the main extant proposals, and then develop a new approach, based semantically on Aczel's notion of Frege structure, which implements a version of {\em subsumption polymorphism. Nominalization is achieved by virtue of the fact that the types of predicative and propositional complements are contained in the type of individuals. Russell's paradox is avoided by placing a type-constraint on lambda abstraction, rather than by restricting comprehension.
(May 1992; 42 pages)
Ref. No: HCRC/RP-30 Price: UKL 1.60

Jacqueline C. Kowtko, Stephen D. Isard and Gwyneth M. Doherty:
Conversational Games Within Dialogue
An analysis of task oriented dialogue has been developed around goal-directed exchanges labelled conversational games. Games account for that aspect of discourse coherence that is manifested in initiation-response-feedback patterns, and they do so by relating the form of dialogue to underlying non-linguistic goals. The system applies to real, spontaneous dialogue and may prove useful in the design of computer dialogue systems. A study was conducted to determine agreement among analysts, upon coding two sets of dialogues. One expert and three novice analysts agreed on an average of 78\% of the moves assigned. When certain consistent differences are taken into account, however, the accuracy increases to 88\%.
(June 1992; 12 pages)
Ref. No: HCRC/RP-31 Price: UKL 0.70

Workshop on Computational Semantics This document reports on a workshop held 5th-8th March, 1992 in which a number of people met to discuss topics relating to the current state and future development of the field of computational semantics. The majority of the time was spent in working groups discussing the issues reported on in this document. The intention is that this report should stimulate furhter discussion in the field.
(July 1992; 29 pages)
Ref. No: HCRC/RP-32 Price: UKL 1.20

Patrick Blackburn:
Structures, Languages and Translations: the Structural Approach to Feature Logic
This paper discusses an approach to feature logic called the structural approach. The method consists in first viewing feature structures as models (or relational structures) in the standard model theoretic sense, and then going on to consider various languages that can be interpreted on these structures and the way these languages are interrelated. It will be shown that the structural approach offers a natural perspective from which to relate various feature logics that have been proposed in the literature, and in addition it will be argued that it suggests strategies for devising interesting and tractable constraint languages.
(August 1992; 28 pages)
Ref. No: HCRC/RP-33 Price: UKL 1.20

Matthew Walter Crocker:
A Logical Model of Competence and Performance in the Human Sentence Processor
This work is concerned with the way in which principal theories of syntax and modular theories of mind may participate in an incremental model of human linguistic performance. Central to current linguistic theory is the distinction between competence, what we know about language, and performance, how we use that knowledge. While current theories of grammar suggest a highly modular, abstract, language universal characterisation of linguistic competence, traditional models of performance have postulated parsing strategies based on construction-oriented, phrase-structure grammars. In contrast, we construct a principled theory of performance on the basis of cross-linguistic evidence, with the aim of shedding greater light on the relationship between grammar and processing.
On the basis of Fodor's Modularity Hypothesis and a range of empiracal evidence, we assume the existence of a distinct syntactic processor within the human sentence processor. We further hypothesize {\it The principle of Incremental Comprehension, entailing that the sentence processing strive to achieve maximal incremental comprehension as each word in a sentence is encountered. To achieve incremental comprehension at the various levels of linguistics processing (syntactic, semantic, etc.) we therefore predict that modules operate concurrently. We then suggest that the modularity paradigm is one to be exploited whenever possible, precisely because it permits distributed processing within a particular domain, thereby improving real-time performance. This maxim of modularity, combined with the natural partitioning of syntactic information into several informationally encapsulated representation types leads us to posit four sub-modules within the syntactic processor: (1) phrase structure, (2) chain structure, (3) conference, and (4) thematic structure. We then present several processing strategies which are claimed to be operative within the phrase structure module and demonstrate how the proposed architecture successfully accounts for a variety of empiracal phenomena, across several languages both the cross-linguistic application and possibly innate status of the model. We further argue that the processing strategies follow from the more general Principle of Incremental Comprehension.
To demonstrate the operation of the proposed model, and illustrate its principled basis, we employ the Algorithm = Logic + Control paradigm of logic programming. In particular, we present a 'deductive' implementation wherein each module is realised as a specialised meta-interpreter which constructs its own representation with respect to the relevant principles of grammar. We then demonstrate how these interpreters may be coroutined' so as to model the concurrency of the performance theory. Finally, we see that the implemented model successfully accounts for subsets of both English and German, without any variation of the control strategy. We take this as further support for the existence of an innate, unparameterised sentence processing mechanism, and discuss some possible implications of this consclusion.
(September 1992; 200 pages)
Ref. No: HCRC/RP-34 Price: UKL 7.70

Richard C Shillcock and Ellen Gurman Bard:
Modularity and the processing of closed-class words
The process of lexical access has been shown to be immune from the effects of syntactic context; it is informationally encapsulated. Thus a listener automatically accesses even the syntactically inappropriate meanings of an ambiguous word like "rose". Two cross-modal priming experiments are presented which demonstrate that the lexical access module is permeable to syntactic information in the case of those closed-class words like "can" and "would" which are homophonous with open-class words: when "would" is heard in context, subjects do not access "wood". Subsequent analyses, along with experiments testing the discriminability of the open- and closed-class tokens and measuring the strength of the syntactic context, suggest that the results are not the result of word frequency effects, but genuinely reflect the deployment of syntactic information. The results are discussed in terms of their implications for the modularity hypothesis and the storage and access of closed-class words.
(September 1992; 17 pages)
Ref. No: HCRC/RP-35 Price: UKL 1.00

Ellen Gurman Bard and Richard C Shillcock:
Competitor Effects during Lexical Access: Chasing Zipf's Tail
The difficulty of recognizing a spoken word appears to be related to at least three different characteristics of the set of similar words or "lexical competitors": the size of the set of competitors (Luce, 1986, Frauenfelder and Peeters, 1990), the aggregate frequency of all competitors (Luce, 1986) and the frequency of the most frequent competitor (Brown, 1987; Grainger @i[et al.] 1988; Marslen-Wilson, 1990). The present paper reconciles these claims by showing that the three measures of competition intercorrelate because of the shape of the distribution of word frequencies in a typical set of lexical competitors. Like the whole lexicon (Zipf, 1935), sets of lexical competitors contain many rare and very few extremely frequent words. Both the word-initial cohorts formed in an exhaustive partitioning of the phonemically transcribed words of the MRC Psycholinguistics Database (Coltheart, 1981) and a set of orthographic neighbours (Andrews, 1989) are shown to have distributions of word frequency expected in random samples from a population with extreme positive skew. These facts stand in contradiction to Landauer and Streeter's (1973) claims that different phonological elements of English are associated non-randomly with different parts of the word-frequency continuum. The same facts permit simplification of lexical access models.
(September 1992; 44 pages)
Ref. No: HCRC/RP-36 Price: UKL 1.60

Jonathan Ginzburg:
Propositional and Non-Propositional Attitudes
The term propositional attitudes, has achieved legitimacy under the assumption that the objects of such activities as claiming, believing, reporting or discovering are individuated by means of a single class of entities, the propositions, a class of descriptively potent entities of which truth and falsity can be predicated, corresponding roughly to their descriptive accuracy. This paper argues that no logically coherent class of entities can simultaneously individuate the potential fillers of the cognitive' argument role of all propositional attitude predicates (PAP's). Thus, it is shown that there exist at least three syntactically distinct classes of expressions, interrogative clauses, verbal gerunds and noun phrases, all of which have uses which denote veridical descriptive entities. And yet a coherent class of PAP's, including the predicate true, cannot felicitously predicate of (uses of) any of these expressions types. It is proposed that this class of predicates can be (partially) characterized in terms of a transparency to predication of truth which their nominally presented arguments exhibit. An account of these data in terms of pragmatic presupposition is considered and argued to be inadequate. This leads to an account reminiscent of but distinct from that propounded at a certain period by Russell. The proposal involves recognizing that two classes of entities that can fill cognitive' argument roles: propositions and states-of-affairs. On the account proposed, which builds particularly on insights of Austin, Vendler and work in Situation Theory. States-of-affairs are entities which can but need not be {\em factual. Truth, however, is not applicable to this class of entities, but rather is a property of propositions, conceived of as predications that a state-of-affairs accurately describes a given part of the world. The paper contains a semantics for declarative and interrogative sentences.
(October 1992; 47 pages)
Ref. No: HCRC/RP-37 Price: UKL 1.70

Jon Barwise and Robin Cooper:
Extended Kamp Notation A Graphical Notation for Situation Theory
This work is part of a project to consolidate recent work on situation theory into a workable version and to solve a represenational problem with situation theory. Our goal here is to design a notation for representing situation-theoretic objects that uses insights from Kamp's discourse representation structures.
(November 1992; 27 pages)
Ref. No: HCRC/RP-38 Price: UKL 1.20

Alistair Knott and Robert Dale:
Using Linguistic Phenomena to Motivate a Set of Rhetorical Relations
The notion that a text is coherent in virtue of the relations' which hold between the elements of that text has become fairly common currency, both in the study of discourse coherence and in the field of text generation. The set of relations proposed in Rhetorical Structure Theory (Mann and Thompson [1987]) has had particular influence in both of these fields. But the widespread adoption of relational' terminology belies a certain amount of confusion about the relational constructs themselves: no two theorists use exactly the same set of relations; and often there seems no motivation for introducing a new relation beyond considerations of descriptive adequacy or engineering expedience.
To alleviate this confusion, it is useful to think of relations not just as constructs with descriptive or operational utility, but as constructs with psychological reality, modelling real cognitive processes in readers and writers.
This conception of rhetorical relations suggests a methodology for delineating a set of relations to work with. Evidence that a relation is actually used by speakers of a language can be obtained by looking at the language itself---in particular by looking at the range of cue phrases the language provides for signalling relations. It is to be expected that simple methods will have evolved for signalling the relations we find most useful.
This paper presents a bottom-up methodology for determining a set of relations on the basis of the cue phrases which can be used to mark them in text. This methodology has the advantage of starting from concrete linguistic data, rather than from controversial assumptions about notions like intention' and `semantics'.
(December 1992; 30 pages)
Ref. No: HCRC/RP-39 Price: UKL 1.20