Date: Wed, 12 Nov 2003 12:57:27 -0500 From: Umarani Pappuswamy Subject: Mental Models and the Interpretation of Anaphora
Garnham, Alan (2001) Mental Models and the Interpretation of Anaphora, Psychology Press Ltd.
Umarani Pappuswamy, Research Associate, Learning Research and Development Center, University of Pittsburgh, USA.
BOOK'S PURPOSE AND CONTENT The origin of the term 'mental model' can be traced back to Kenneth Craik (1943). Craik pointed out that the mind constructs "small-scale models" of reality that it uses to translate external events into internal models and also reason about these representations. There has been a considerable amount of research in this area following Craik. Some of the significant works are by cognitive scientists such as Miller, Galanter and Pribram 1960, Newell and Simon 1976, Johnson-Laird 1980, Johnson-Laird and Garnham 1986, Garnham, Oakhill, and Johnson- Laird 1982, Marr 1982 Garnham 1987, Garnham and Oakhill 1989. Though all these studies (from visual perception to discourse processing) have their own diversities, they all invoke the mental-model hypothesis in various forms. In processing a discourse, it is very important to have a better comprehension of a text in order to make inferences necessary for a coherent interpretation. Humans construct 'mental models' of the situations in the discourse as they perceive them. The mental model, thus constructed, should be able to resolve an anaphoric expression, if any, present in the discourse. The research outlined in this book presents an overview of the author's research on anaphor interpretation set within the context of mental models on anaphora from the disciplines of psycholinguistics, philosophy, linguistics, and computational linguistics. He argues that '..the notion of a mental model is essential in the detailed description of the processes of anaphor resolution' (p. ix).
The entire book is presented in eleven chapters. A brief description/summary about the chapters are given below:
Chapter 1: This chapter gives an introduction to the theme of the book. The author talks about Marr (1982)'s theory of visual processing and compares his own goals with that of Marr's with regard to mental processing. Marr focussed on visual processing whereas Garnham concentrates on text comprehension. The main focus is about the interpretation of anaphoric expressions in text, such as definite and indefinite pronouns, and elliptical verb phrases. The author claims that in the interpretation of anaphoric expressions, the construction of a representation of part of a world is essential. Marr attempted to focus on the "what" of visual processing though he does give some hints about his answer to the "why". Garnham, on the other hand, tries to seek answers for both these questions in his book.
Chapter 2: Garnham studies the nature of mental representations of a text, and in particular, the question of what components they are built from. The chapter discusses at length as what constitutes a 'mental model' of a text and what kinds of things are represented in the mental model. He turns to linguistic semantics for answers starting from Montague (1973)'s model of formal semantics. For Montague, texts are about individuals, and entity and truth values (e & t) are the two fundamental semantic types. After a critical observation of these types, Garnham points out that Montague has not given importance to 'events and properties' as basic semantic types. Though Montague did not deny the existence of properties, he regarded it be derivative (from e & t), and he did not have a place for events in his system. Montague's system is based only on individual sentences. This approach seems to be inadequate and this reviewer also agrees with Garnham on this aspect. The author also provides evidences from various other scholars, Davidson (1967) and Parsons (1990) to argue that Montague's model is inadequate when discourse is considered. He quotes Prior (1968), Kamp (1978), Kamp and Rohrer (1983) and emphasizes that both properties and events are represented directly in mental models. He also provides facts that events are related to one another (spatial, temporal, logical, causal, intention and moral) to support his claim.
Chapter 3: This chapter introduces mental models theory as a psychological theory, focussing on its application to language processing. As is well known, many aspects of language use depends on an individual's cognitive ability. Garnham discusses the scope, the symbolic nature, and assumptions of mental models theory. In addition to the assumptions of mental models theory, he describes some assumptions that are particular to the theory as applied to language processing (incremental processing). A theory of comprehension is worked out - the detailed mechanisms that extract information from the current piece of text, and add it to the mental model should be specified. This interpretation keeps on updating the model and provides the context for interpreting the next piece of text. This forms the core of the book in interpreting anaphoric expressions. The author points out that 'integration' and 'construction' are two important aspects in text comprehension and that mental models are considered to be central to both these aspects. He also gives an outline of what a theory of language processing should explain: 'explicit content of a text, orgranisation of knowledge to make inferences'. He also hints at the complexities involved in constructing mental models with syntactic and semantic knowledge of the text in a study.
Chapter 4: In this chapter, the author presents an overview of linguistic approaches to anaphora. He looks into the way linguists handle nominal and verbal anaphora, and states that the goals and methods/approaches to anaphora of psycholinguists differ from linguists in many ways. The psychologistic approach should explain why sometimes people use anaphoric expressions in ways that linguistic descriptions forbid. He also discusses the morphological and syntactic issues related to anaphora and cataphora using English language as an example. The syntactic constraints and discourse constraints on anaphora are also examined at depth.
Chapter 5: The fifth chapter introduces the methodologies used in the psycholinguistic analysis of anaphors. It discusses the techniques such as self-paced reading, eye-movement monitoring, and priming. According to Garnham, self-paced techniques are straightforward to set up and the analyses can be carried out in a much easier way than the other methods. Eye-monitoring technique has an advantage over self-paced reading in that the text can be presented in a normal form to the user. Priming and paper-pencil tests are also mentioned here. He feels that all these techniques have their own problems and suggests that it is very secure to use a combination of several techniques in studying anaphoric expressions of a text than using a single technique. The author also makes an attempt to study the processing of anaphoric expressions on a corpus ,collected by himself and Jane Oakhill, over a period of years from published and publicly "broadcast" material. The results of the study showed that 'many uses of anaphoric expressions fall foul of linguistic prescriptions, but do not cause overt difficulties in comprehension' (p. 63). it was concluded that there is no straightforward relation between linguistic prescription about how anaphoric expressions should be used and the way they are interpreted.
Chapter 6: This chapter focuses on various empirical studies on anaphora from a psycholinguistic perspective. He turns his attention to three important aspects to the interpretation of anaphoric expressions as outlined by him in 1987: 1. identifying the anaphor 2. recognizing the context under which the anaphor occurs and 3. deriving the meaning of the anaphor from its semantic content and from the associated context. Once the anaphoric expression has been identified, it is easy to fix the appropriate meaning to it based on the context using linguistic cues. Psycholinguists have observed many factors that influenze the interpretation of anaphors. These include morphosyntactic factors (gender, number, case and animacy, and the binding relations of syntactic theories) Stylistic factors, discourse-based factors (local and global foci), Clause and sentence boundaries and knowledge-based (pragmatic) factors. It should be noted that the author talks only about the interpretation of 'pronominal' anaphors, and that too only 'definite' pronouns and nouns. Abstract anaphors such as 'this, that and it' may pose challenging issues for constructing appropriate mental models for resolving the same.
Chapter 7 discusses the two classes of anaphoric expressions (deep and surface) linguists use. The linguistic theory behind this postulated by Sag and Hankamer (1984) is presented in detail. They renamed 'surface anaphors' as 'ellipses' and 'deep anaphors' as 'model-interpretive' anaphors. The criterion under which these anaphors can be distinguished from each other is outlined . Garnham presents summaries of some of the psycholinguistic studies on deep and surface anaphors and also observes that though the linguistic theory provides a good account of grammaticality judgement, there is no adequate experimental evidence to support the processing theory (as laid out by Sag and Hankamer ).
Chapter 8 discusses anaphoric islands. Referring back to Ross (1967) and Postal (1969), the author provides explanation for the notion of an anaphoric island. This kind of situation arises only when a definite pronoun, has a meaning that does not correspond in a straightforward way to the meaning of another expression in the surrounding text. The author summarizes works of Postal and other linguists, each emphasizing morphological or syntactic or semantic or a combination of these processes to account for the acceptability of the references. Postal (1969)'s arguments were from a generative semantic point of view and his claim was that references into anaphoric islands were always unacceptable, even when the intended interpretation of the anaphor and the antecedent are morphologically related (cf. this author, p. 112). However, Corum 1973, Lakoff & Ross 1972 counter-argued Postal's claim. Furthermore, Lakoff and Ross also argue that the acceptance of an anaphoric reference relied on the syntactic relation between the antecedent and the anaphor in addition to their morphological relation. Browne (1974) showed that reference into an anaphoric island required a semantic relation between the anaphoric island and the natural interpretation of the pronoun besides their morphological relation (contrary to Postal's and Corum's claims, as a part-whole relation between the meaning of the anaphor and the antecedent trigger). Mohanan (1986) explained the anaphoric island data within the theories of lexical morphology and phonology. The author also summarizes many other works related to this concept (see the chapter for details).
Chapter 9: Garnham presents a neat overview of the notion of implicit causality and empirical studies on the same. 'Implicity causality' was first introduced by Garvey and Caramazza (1974) who suggested that this phenomenon was primary associated with verbs and using sentence completions they divided the verbs into three categories (p. 124). Although Garvey et. al (1975) considered, and rejected, the use of Fillmore's case roles to explain this phenomenon for two reasons (the effect of social status and the effects of passivisation cannot be explained by case roles) other authors like Brown and Fish (1983) used 'semantic roles' to describe them. They identified two patterns: action verbs impute causes to their agents, rather than their patients, and that mental state verbs impute causes to their stimuli, rather than to the experiencer (p. 126). Both approaches have their own limitations. The rest of the chapter summarizes the empirical studies (including his own studies) related to consistency between implicit and exlicit causes, the notion of early and late effects of implicit causality and a section on implicit consequentiality.
Chapter 10: This chapter is about stereotypes in texts. 'There are a set of nouns that, while not specifying the sex of the person that they apply to as part of their meaning, more commonly apply to people of one sex than the other, nouns such as "nurse" and "engineer". Such nouns can be referred to as stereotyped. (p.140)". Garnham presents the results of many studies (including his own) on stereotyping whose claim was to show that, when a text containing a stereotyped noun was introduced, a following clause containing the pronoun that matches the stereotype noun is read more quickly than one in which the pronoun does not match the stereotype.
The final chapter, namely, Chapter 11 reviews some of the themes associated with the mental models theory of anaphoric interpretations of text presented in the earlier chapters. It concludes by saying that mental models are a crucial component of the theory of text comprehension, and they indeed play a significant role in the interpretation of anaphoric expressions.
Lastly, the author presents a neat compilation of the references running from pages 149 - 162, followed by an Author Index and a Subject Index.
OVERALL COMMENTS There is no doubt that this book is an excellent source of psycholinguistic research within the context of anaphoric interpretation of texts. All the chapters are well-written with a good coverage of a broad range of the topics and empirical studies (if any) related to the subject matter. Each chapter can be read and understood independently. The author also provides a short summary at the end of each chapter. There are no footnotes or endnotes (which of course, doesn't make the reader to see the end of the page or flip pages to continue the thread of comprehension). It would have been wonderful if co-indexing of pronouns with the possible antecedents was made (as found in most of the works related to anaphoric resolution). This work focuses only on pronominal anaphors - one or two chapters on the resolution of abstract entity anaphors (this, that and it) would have thrown some light on how the theory of mental models can be applied to the interpretation of texts involving abstract objects. However, this reviewer feels that this book has a lot to offer and will be of interest to linguists, psycholinguists, philosophers and cognitive scientists working in this field of research. This book is also a good source of information for a lay person - to be more precise, the review and originality of the works presented here are accessible to those not already familiar with the subject content, and would definitely prove to be a stepping stone for further research in this area. It could also be used as a text book in psycholinguistic courses.
(I list only the references cited under the section 'Book's purpose and content'. All other references cited in the body of this review can be found in the book).
Craik, K. 1943. The nature of explanation. Cambridge, UK: Cambridge University Press.
Garnham, A., Oakhill, J. V., and Johnson-Laird, P. N. 1982. Referential continuity and the coherence of discourse. Cognition 1: 29-46.
Garnham, A.1987. Mental Models as Representations of Discourse and Text. Chichester: Ellis Horwood.
Garnham, A., and Oakhill, J. V.1989. The everyday use of anaphoric expressions: Implications for the 'Mental Models' theory of text comprehension. In N.E. Sharkey ed., Modelling Cognition: All Annual Review of Cognitive Sciences. Vol. 2. Norwood, NJ:Ablex.
Johnson-Laird, P. N. 1986. Conditionals and mental models: In E. C. Traugott, A. ter Meulen, J. S. Reilly and C. A. Ferguson, eds. On Conditionals. Cambridge, MA: Harvard University Press.
Johnson-Laird, P. N., and Garnham, B. G. 1980. Descriptions and discourse models. Linguistics and Philosophy 3:371-393.
Marr, D. 1982. Vision: A Computational Investigation in the Human Representation of Visual Information. San Francisco: Freeman.
Miller, G.A. , Galanter, E., and Pribram,K. 1960. Plans and the Structure of Behaviour. New York: Holt, Reihart, and Winston.
Newell, A., and Simon, H. A. 1976. Computer science as empirical inquiry: Symbols and search. Communications of the ACM 19:113-126.
ABOUT THE REVIEWER:
ABOUT THE REVIEWER
Dr. Umarani Pappuswamy is a research associate at LRDC, University of Pittsburgh, USA. She has a Ph.D. in Linguistics with specialization in computational linguistics. Her main areas of research interests are: computational semantics - knowledge representation and knowledge reasoning, discourse analysis, typology - syntax, morphology and semantics, and corpus linguistics.