Coherence and coreference

Coherence in conversations and in texts can be partially characterized by a set of coherence relations, motivated ultimately by the speaker's or writer's need to be understood. In this paper, formal definitions are given for several coherence relations, based on the operations of an inference system; that is, the relations between successive portions of a discourse are characterized in terms of the inferences that can be drawn from each. In analyzing a discourse, it is frequently the case that we would recognize it as coherent, in that it would satisfy the formal definition of some coherence relation, if only we could assume certain noun phrases to be coreferential. In such cases, we will simply assume the identity of the entities referred to, in what might be called a “petty conversational implicature,” thereby solving the coherence and coreference problems simultaneously. Three examples of different kinds of reference problems are presented. In each, it is shown how the coherence of the discourse can be recognized, and how the reference problems are solved, almost as a by-product, by means of these petty conversational implicatures.     

An ERP investigation of binding and coreference

This study examines the nature of violations in processing one class of binding construction, namely those involving reflexives and their antecedents. When arguments of verbs appear at the point where a syntactic violation is detected, a centroparietal positivity occurs, peaking at 600 ms after the presentation of the stimulus (P600), as is consistent with other types of syntactic anomalies. However, nonarguments in similar sentences fail to elicit the same response. For example, the reflexive in "John's brothers like himself" is in an argument position and elicits the P600 when compared to its grammatical counterpart. The nonargument, participating in the same type of mismatch, "John's brothers like Bill and himself," does not elicit the same positivity. This provides evidence that there are two processes involved in parsing this binding construction, one syntactic and another as yet unidentified, perhaps involving meaning or pragmatics.     

Comprehension of pronouns

An experiment is reported in which subjects had to choose referents for pronouns in sentences such as: John blamed Bill because he spilt the coffee. To examine whether the choice of referent is influenced by features of the main verb or by the events described in the sentence, the relation between the events was altered by changing the conjunction. A significant effect of conjunction was obtained, but only when both antecedents matched the gender of the pronoun. When only one antecedent matched the pronoun, referents were chosen faster. From these results it is argued that readers use general knowledge to select referents for pronouns when gender does not identify a unique referent. A further effect of sentence structure on the time taken to select a referent was interpreted as showing that subjects analysed the sentences clause by clause.     

Sentence comprehension and relative pronouns

Doubly self-embedded sentences, differing only in whether the relative pronouns were present or deleted, were presented to two groups of Ss who were required to respond to a word beginning with a particular letter in each sentence and to paraphrase the sentence. The results of both the phoneme monitor task and the paraphrase task indicated that comprehension was better when the relative pronouns were present than when they were deleted. These results are consistent with earlier results for the paraphrase task but are not consistent with earlier results for the phoneme monitor task. Possible reasons for the inconsistency were considered. It was concluded that the phoneme monitor task does reflect comprehension difficulty in a manner consistent with the paraphrase task and that deleting the relative pronouns does make comprehending self-embedded sentences more difficult.     

Opacity,Transparency, and the Paradox of the Accessibility Requirement

Key issues in epistemology for the most part have to do with epistemic values such as justification, truth, and knowledge—that is, values related to the epistemic status of our propositional attitudes, mental events, and states. However, another important issue that is worth examining is the extent to which a subject is in a position to evaluate the strength of her epistemic position. In this paper, I wish to emphasize two properties of our mental states that play a decisive part in that respect: their opacity and transparency. In the following, I will assume that a mental state is opaque whenever it presents itself with no underlying reason, whereas states that are supported by apparent reasons are transparent. One main argument that I will defend is that even when the opacity and transparency of our mental states are not reliable cues, still they remain highly informative. Notably, I draw some implications relative to the externalist/internalist debate in epistemology. I examine the claim that only mental states that are justified are well grounded or justification conferring and the idea that often stands behind, that is, that only states whose reasons are accessible are justified—namely, the Accessibility Requirement. I also examine the source of a recent debate in epistemology: the epistemic status of our intuitive states, as these are perfect instances of opaque mental states. I conclude that intuitive states in some respect are less misleading than states that are supported by apparent reasons.     

Distinguishing the time course of lexical and discourse processes through context, coreference, and quantified expressions

How does prior context influence lexical and discourse-level processing during real-time language comprehension? Experiment 1 examined whether the referential ambiguity introduced by a repeated, anaphoric expression had an immediate or delayed effect on lexical and discourse processing, using an eye-tracking-while-reading task. Eye movements indicated facilitated recognition of repeated expressions, suggesting that prior context can rapidly influence lexical processing. However, context effects at the discourse level affected later processing, appearing in longer regression-path durations 2 words after the anaphor and in greater rereading times of the antecedent expression. Experiments 2 and 3 explored the nature of this delay by examining the role of the preceding context in activating relevant representations. Offline and online interpretations confirmed that relevant referents were activated following the critical context. Nevertheless, their initial unavailability during comprehension suggests a robust temporal division between lexical and discourse-level processing.     

Fictional coreference as a problem for the pretense theory

There seems to be a perfectly ordinary sense in which different speakers can use an empty name to talk about the same thing. Call this fictional coreference. It is a constraint on an adequate theory of empty names that it provide a satisfactory account of fictional coreference. The main claim of this paper is that the pretense theory of empty names does not respect this constraint.

The Logic of Opacity

We explore the view that Frege's puzzle is a source of straightforward counterexamples to Leibniz's law. Taking this seriously requires us to revise the classical logic of quantifiers and identity; we work out the options, in the context of higher‐order logic. The logics we arrive at provide the resources for a straightforward semantics of attitude reports that is consistent with the Millian thesis that the meaning of a name is just the thing it stands for. We provide models to show that some of these logics are non‐degenerate.     

In search of referents for nouns and pronouns

In comprehending a sentence, people normally try to identify the objects, events, and states referred to by its definite noun phrases. In Experiment 1, subjects took less time comprehending a sentence when the referents of such noun phrases were mentioned one sentence back than when they were mentioned two or three sentences back. There appeared to be a discontinuity between the first and second sentences back. Experiments 2 and 3 showed that it was most likely the first clause back, not the first sentence back, that was critical. These findings suggest that, independent of other factors, the last clause processed grants the entities it mentions a privileged place in working memory. They are readily available to be referred to by nouns and pronouns.     

Linguistic and cognitive prominence in anaphor resolution: topic,contrastive focus and pronouns

This paper examines the role that linguistic and cognitive prominence play in the resolution of anaphor–antecedent relationships. In two experiments, we found that pronouns are immediately sensitive to the cognitive prominence of potential antecedents when other antecedent selection cues are uninformative. In experiment 1, results suggest that despite their theoretical dissimilarities, topic and contrastive focus both serve to enhance cognitive prominence. Results from experiment 2 suggest that the contrastive prosody appropriate for focus constructions may also play an important role in enhancing cognitive prominence. Thus different types of linguistic prominence (topic, contrastive focus) appear to have the common effect of increasing the cognitive prominence of the discourse referent. For pronouns with two possible antecedents, the cognitive prominence of an antecedent aids in anaphor resolution, immediately biasing selection towards the more prominent (and ultimately preferred) antecedent.

The role of structure in coreference assignment during sentence comprehension

This paper examines the role of symtactic constraints on the reactivation and assignment of antecedents to explicit and implicit anaphoric elements during sentence comprehension. Evidence from on-line studies examining the time course of coreference processing supports the view that reactivation of potential antecedents is restricted by grammatical constraints when they are available. When structural information cannot serve to constrain antecedent selection, then pragmatic information may play a role, but only at a later point in processing.     

An electrophysiological investigation of the effects of coreference on word repetition and synonymy

In two experiments the effects of word repetition, synonymy, and coreference on event-related brain potentials during text processing were studied. Participants read one (Experiment 1) or two sentence (Experiment 2) texts in which critical nouns were preceded by the definite (the) or indefinite (a) articles. Experiment 1 was run as a control to verify that differences in article processing in the second sentences of Experiment 2 would not contaminate the ERPs to critical noun items. They did not. In Experiment 2, an initial sentence was used to set up a context and contained either a first presentation or synonym of the critical word from the second sentence. N400 (but not Late Positive Component; LPC) priming effects were found for repetitions and synonyms (larger for repetitions) in second sentences. This extends observations of priming in word lists and single sentences to two-sentence texts. There was also a greater left anterior negativity or "LAN" for coreferential critical nouns (those following the article "The") compared to non-coreferential critical nouns (those following the article "A") suggesting that ERPs are sensitive to working memory processes engaged during referential assignment. In response to the articles themselves, there was a greater N400-700 elicited by the article "A" vs. "The." Finally, there was a greater N400-like negativity to the final words of non-coreferential sentences implying that the meanings of these sentences were difficult to integrate with the discourse level representation established by the prior sentence.     

Eye movements during the production of nouns and pronouns

Earlier research has established that speakers usually fixate the objects they name and that the viewing time for an object depends on the time necessary for object recognition and for the retrieval of its name. In three experiments, speakers produced pronouns and noun phrases to refer to new objects and to objects already known. Speakers looked less frequently and for shorter periods at the objects to be named when they had very recently seen or heard of these objects than when the objects were new. Looking rates were higher and viewing times longer in preparation of noun phrases than in preparation of pronouns. If it is assumed that there is a close relationship between eye gaze and visual attention, these results reveal (1) that speakers allocate less visual attention to given objects than to new ones and (2) that they allocate visual attention both less often and for shorter periods to objects they will refer to by a pronoun than to objects they will name in a full noun phrase. The experiments suggest that linguistic processing benefits, directly or indirectly, from allocation of visual attention to the referent object.     

Grammatical priming effects between pronouns and inflected verb forms

Summary Deciding on the lexical status of a word can be facilitated by a preceding, semantically related word. Three experiments are reported demonstrating a different kind of facilitation due to the grammatical relation between function words and content words in Serbo-Croatian. A pronoun facilitated or inhibited the lexical decision on a following verb depending on whether the person of the verb, as represented by its inflected ending, agreed with the person of the pronoun. Also, verbs primed subsequent pronouns but the pattern of results for the verbal priming of pronouns was markedly different from that for the pronominal priming of verbs. The results suggest that the organization of the internal lexicon is sensitive to grammatical relations as well as semantical relations between words.     

Inference and children's comprehension of pronouns

Two experiments are reported that investigate the ability of 5 year olds to determine the reference of anaphoric pronouns. The first study shows that children have problems coping with more than one pronoun in a sentence and if they have to draw an inference to define the reference of a pronoun. The second study shows that the difficulty in assigning reference is not due to children merely forgetting the premise information but is due to the difficulty of carrying out the inference. There is an indication in the second study that some of the children may be using a syntactically oriented rule (that the pronoun should be assigned to a noun phrase that has a parallel function in the previous sentence), and that they are not drawing the appropriate inferences.