Incremental Centering and Center Ambiguity

In this paper, we present a model of anaphor resolution within the framework of the centering model. The consideration of an incremental processing mode introduces the need to manage structural ambiguity at the center level. Hence, the centering framework is further refined to account for local and global parsing ambiguities which propagate up to the level of center representations, yielding moderately adapted data structures for the centering algorithm.Comment: 6 pages, uuencoded gzipped PS file (see also Technical Report at: http://www.coling.uni-freiburg.de/public/papers/cogsci96-center.ps.gz

Syntactic Reanalysis in Human Language Processing

Institute for Communicating and Collaborative SystemsThis thesis combines theoretical, computational and experimental techniques in the study of reanalysis in human sentence comprehension. We begin by surveying the main claims of existing theories of reanalysis, and identify representation preservation as a key concept. We show that the models which most obviously feature representation preservation are those which have been formulated with in the monotonicity framework, which assumes that there are aspects of representation which are updated monotonically (i.e.non-destructively) from state to state, and that any reanalysis which requires a non-monotonic update is predicted to cause processing disruption. Next, we present a computational implementation, based on the monotonic theory of Gorrell (1995b). We argue that in constructing such a model of reanalysis, it is essential to consider not only declarative constraints, but also the computational processes through which reanalysis routines explicit, leading to novel predictions in cases where there exist more than one alternative for structural revision. I show why preferences for such reanalysis ambiguities may differ between predominantly head initial languages such as English, and head final languages such as Japanese. After this, we consider the empirical consequences of the implemented model, in particular in relation to recent experimental data concerning modifier attachment. We shoe that the model is too restrictive, and we argue that the appropriate way to expand its coverage is to apply the monotonicity constraints not directly to phrase structure, but to thematics structure. We provide a general framework which allows such non-phrase structural models to be defined, maintaining the same notion of monotonicity that was employed in the previous model. We go on to provide solutions to some computational problems which accompany this change. Finally, we present two experimental studies. The first of these considers the issue of reanalysis ambiguity, and specifically the existence of a recency preference is confirmed in off-line tasks, such as comprehension accuracy and a questionnaire experiment, but is not confirmed in self-paced reading. We discuss some possible reasons for this dissociation between the on-line and off-line results. The second experimental study considers the effect of modifier attachment in Japanese relative clause ambiguities. In this study, we confirm the influence of thematic structure on the resolution of Japanese relative clause ambiguities, and we argue that this effect should be interpreted in terms of a constraint on reanalysis

Processing long-distance dependencies: an experimental investigation of grammatical illusions in English and Spanish

A central concern in the study of sentence comprehension has to do with defining the role that grammatical information plays during the incremental interpretation of language. In order to successfully achieve the complex task of understanding a linguistic message, the language comprehension system (the parser) must – among other things – be able to resolve the wide variety of relations that are established between the different parts of a sentence. These relations are known as linguistic dependencies. Linguistic dependencies are subject to a diverse range of grammatical constraints (e.g. syntactic, morphological, lexical, etc.), and how these constraints are implemented in real-time comprehension is one of the fundamental questions in psycholinguistic research. In this quest, the focus has been often placed on studying the sensitivity that language users exhibit to grammatical contrasts during sentence processing. The grammatical richness with which the parser seems to operate makes it even more interesting when the results of sentence processing do not converge with the constraints of the grammar. Misalignments between grammar and parsing provide a unique window into the principles that guide language comprehension, and their study has generated a fruitful research program

Linguistic Representation and Processing of Copredication

This thesis addresses the lexical and psycholinguistic properties of copredication. In particular, it explores its acceptability, frequency, crosslinguistic and electrophysiological features. It proposes a general parsing bias to account for novel acceptability data, through which Complex-Simple predicate orderings are degraded across distinct nominal types relative to the reverse order. This bias, Incremental Semantic Complexity, states that the parser seeks to process linguistic representations in incremental stages of semantic complexity. English and Italian acceptability data are presented which demonstrate that predicate order preferences are based not on sense dominance but rather sense complexity. Initial evidence is presented indicating that pragmatic factors centred on coherence relations can impact copredication acceptability when such copredications host complex (but not simple) predicates. The real-time processing and electrophysiological properties of copredication are also presented, which serve to replicate and ground the acceptability dynamics presented in the thesis

The Architecture Underlying Syntactic Processing

In this thesis, I report five eyetracking experiments that tested current sentence processing theories. So far, most research has attempted to discriminate between various sentence processing theories by investigating whether non-syntactic sources of information can be employed immediately in syntactic ambiguity resolution. Two-stage theories such as the garden-path theory claim that the use of non-syntactic information is delayed, whereas interactive or constraint-based theories claim that all sources of information can be employed immediately. The experiments in this thesis focussed on a different aspect of current sentence processing theories, which has been largely ignored. They investigated whether the architecture of the sentence processor involves reanalysis or competition. Two-stage theories claim that processing difficulty occurs when an initially adopted syntactic analysis has to be revised, whereas most current constraint-based theories stipulate that competition between two or more syntactic analyses that are activated in parallel makes a sentence difficult to process. The experiments in this thesis investigated reanalysis and competition by testing globally ambiguous syntactic structures and contrasting them with structures that are disambiguated (either to one analysis or the other). Constraint-based competition theories predict that competition occurs in globally ambiguous sentences which do not have a bias for one structure over another, because two syntactic analyses are about equally activated. No such competition should occur in disambiguated sentences, because only one analysis is supported by the disambiguating information. In contrast, traditional two-stage theories such as the garden-path theory predict that the processor initially adopts the structurally preferred analysis. When the disambiguation is inconsistent with this analysis, reanalysis should occur. Reanalysis should not occur when a sentence is disambiguated toward its preferred analysis, or when a sentence is globally ambiguous. The eyetracking experiments in this thesis showed that disambiguated sentences are more difficult to read than globally ambiguous sentences. These results are incompatible with competition as a mechanism of syntactic ambiguity resolution, and therefore disconfirm the predictions of most current constraint-based theories. They are also problematic for some two-stage theories, because processing difficulty occurred in sentences where the disambiguation was toward the structurally preferred analysis. In this thesis an alternative model, the unrestricted race model, is proposed, which explains the results in a straightforward manner. The unrestricted race model claims that the alternative analyses of a syntactically ambiguous sentence are engaged in a race. The analysis that is constructed fastest is adopted. The model stipulates that the analysis that receives most support from both syntactic and non-syntactic sources of information usually wins the race. When two analyses are about equally supported, as in balanced ambiguities, each analysis is adopted about half the time. Consequently, when the sentence is disambiguated (toward one analysis or the other), it is inconsistent with the analysis on half the trials, and therefore reanalysis should occur on those trials. Thus, the disambiguated sentences are more difficult than the ambiguous sentences, where reanalysis does not occur. Balanced ambiguities contrast with biased ambiguities, where there is a preference for one analysis. The unrestricted race model predicts that in such ambiguities, the processor adopts the preferred analysis on nearly all trials. Therefore, reanalysis should occur on very few trials when the disambiguation is consistent with this preference

The Processing of Emotional Sentences by Young and Older Adults: A Visual World Eye-movement Study

Carminati MN, Knoeferle P. The Processing of Emotional Sentences by Young and Older Adults: A Visual World Eye-movement Study. Presented at the Architectures and Mechanisms of Language and Processing (AMLaP), Riva del Garda, Italy