Research

Studies of adult sentence processing have established that the referential context in which sentences are presented plays an immediate role in their interpretation, such that features of the referential context mitigate, and even eliminate, so-called 'garden-path' effects. The finding that the context ordinarily obviates garden path effects is compelling evidence for the Referential Theory, advanced originally by Crain and Steedman, (1985) and extended in Altmann and Steedman (1988). Recent work by Trueswell, Sekerina, Hill and Logrip (1999) suggests, however, that children may not be as sensitive as adults to contextual factors in resolving structural ambiguities. This conclusion is not anticipated by the Referential Theory and it also runs counter to the Continuity Assumption, which supposes that children and adults access the same cognitive mechanisms in processing language. The purpose of this work was to reexamine the observations that have led researchers to conclude that children, unlike adults, may lack sensitivity to features of the referential context in comprehension and ambiguity resolution. A series of experiments has been conducted to evaluate this conclusion. The findings show that the performance systems of children and adult differ minimally. Children are sensitive to the same features of the referential context as adults are, and they make use of the context to resolve structural ambiguities in sentence interpretation. In addition, the present study provides evidence in favor of children's pragmatic and semantic knowledge.

In two experiments, we tested for lingering effects of verb replacement disfluencies on the processing of garden path sentences that exhibit the main verb/reduced relative (MV/RR) ambiguity. Participants heard sentences with revisions like "The little girl chosen, uh, selected for the role celebrated with her parents and friends." We found that the syntactic ambiguity associated with the reparandum verb involved in the disfluency (here "chosen") had an influence on later parsing: Garden path sentences that included such revisions were more likely to be judged grammatical if the reparandum verb was structurally unambiguous. Conversely, ambiguous non-garden path sentences were more likely to be judged ungrammatical if the structurally unambiguous disfluency verb was inconsistent with the final reading. Results support a model of disfluency processing in which the syntactic frame associated with the replacement verb ‘‘overlays’’ the previous verb’s structure rather than actively deleting the already-built tree.

In noisy settings, seeing the interlocutor's face helps to disambiguate what is being said. For this to happen, the brain must integrate auditory and visual information. Three major problems are (1) bringing together separate sensory streams of information, (2) extracting auditory and visual speech information, and (3) identifying this information as a unified auditory-visual percept. In this dissertation, a new representational framework for auditory visual (AV) speech integration is offered. The experimental work (psychophysics and electrophysiology (EEG)) suggests specific neural mechanisms for solving problems (1), (2), and (3) that are consistent with a (forward) 'analysis-by-synthesis' view of AV speech integration. In Chapter I, multisensory perception and integration are reviewed. A unified conceptual framework serves as background for the study of AV speech integration. In Chapter II, psychophysics testing the perception of desynchronized AV speech inputs show the existence of a ~250ms temporal window of integration in AV speech integration. In Chapter III, an EEG study shows that visual speech modulates early on the neural processing of auditory speech. Two functionally independent modulations are (i) a ~250ms amplitude reduction of auditory evoked potentials (AEPs) and (ii) a systematic temporal facilitation of the same AEPs as a function of the saliency of visual speech. In Chapter IV, an EEG study of desynchronized AV speech inputs shows that (i) fine-grained (gamma, ~25ms) and (ii) coarse-grained (theta, ~250ms) neural mechanisms simultaneously mediate the processing of AV speech. In Chapter V, a new illusory effect is proposed, where non-speech visual signals modify the perceptual quality of auditory objects. EEG results show very different patterns of activation as compared to those observed in AV speech integration. An MEG experiment is subsequently proposed to test hypotheses on the origins of these differences. In Chapter VI, the 'analysis-by-synthesis' model of AV speech integration is contrasted with major speech theories. From a Cognitive Neuroscience perspective, the 'analysis-by-synthesis' model is argued to offer the most sensible representational system for AV speech integration. This thesis shows that AV speech integration results from both the statistical nature of stimulation and the inherent predictive capabilities of the nervous system.

This dissertation suggests that referential 3rdP null subjects in Modern Brazilian Portuguese (BP) and Finnish are residues of A-movement, rather than null pronouns. These grammars exhibit weak 3rdP verbal and possessive agreement morphology, and do not obey the Avoid Pronoun Principle, allowing non-emphatic overt pronouns in subject position. This state of affairs has affected the licensing of referential null subjects, which are licensed only within embedded domains. I correlate the loss of agreement with this peculiar behavior of null subjects and advance the hypothesis that BP and Finnish are not pro-drop grammars, arguing on empirical grounds that in BP and Finnish null subject inside the embedded clauses and possessive DPs are residues of A-movement. Putting it boldly, these null subjects are salient copies of their antecedents. The arguments I present in favor of a movement analysis are: (i) Finnish and BP null subjects have an anaphoric behavior, requiring a sentential antecedent, which is the closest c-commanding DP. (ii) They cannot occur within relative clauses if the head of the relative clause intervenes between them and their antecedents. (iii) They display all the diagnostics used to characterize obligatory control as formed by movement; (iv) They do not occur inside paratactic constructions. (v) Inside coordinated DPs, they must occur in an across-the-board fashion. (vi) Floating quantifiers and participial forms within their c-command domains agree with their antecedents in f-features. Presupposing that in pro-drop languages pro is the verbal agreement morpheme (Agr) itself, I suggest in that in BP and Finnish Agr underwent f-degradation and was lexically reanalyzed as part of the verb. However, it is hypothesized that in these languages Agr retained a D-feature, and, consequently, it can satisfy the EPP feature of a Case-checking functional projection. As result, in these grammatical systems, a DP can undergo A-movement out of a Case-domain.

This dissertation consists of an investigation of Syntactic Amalgamation (cf. Lakoff 1974): the phenomenon of combination of sentences that yields parenthetic-like constructions like (01). (01) John invited God only knows how many people to you can imagine what kind of a party. The theoretical framework adopted is the Generative-Transformational Grammar (Chomsky 1957, 1965, 1975, 1981, 1986b, 2000b), following (and elaborating on) the recent developments known as the Minimalist Program (Chomsky 1995, 2000a, 2001a, 2001b; Martin & Uriagereka 2000; Uriagereka 1998, 1999, 2002). As far as the representation of syntactic amalgams is concerned, the main claim made in this dissertation is that such constructions involve a radical form of shared constituency, where two or more matrix sentences share the same subordinate sentence, in a multiply-rooted phrase marker. As far as the derivation of syntactic amalgams is concerned, the main claims made in this dissertation are: (i) context-free shared constituency arises from overlapping numerations; and (ii) the computational system builds structure incrementally, in a generalized tucking-in fashion, which yields a left-to-right/top-to-bottom effect on the derivation, such that constituency is heavily dynamic (along the lines of Phillips 1996, 2003; Drury 1998a, 1998b, 1999; Richards 1999, 2003). The conclusion is that this particular kind of paratactic-like construction is better understood as a purely syntactic phenomenon, where the resources of the computational system are pushed to the limit.

This dissertation presents a Minimalist Theory of Control. As for the distribution of PRO, it provides evidence that PRO appears in a configuration of regular Structural Case assignment. This suggests that the complementary distribution between PRO and lexical subjects is not related to Case. It also provides empirical evidence against the Movement analysis of Control, which subsumes Control under Raising, and is compatible with the theoretical view that Theta Roles are configurational, rather than Features. It also renders the so-called Null Case unnecessary. The interpretation of PRO is the result of the need of the Chain of PRO to collapse with the Chain of the antecedent in order to survive at LF. Specifically, PRO is a featureless element and it is not in the Numeration. However, the system resorts to the off-line insertion of PRO to the Derivation to satisfy Theta Theory. This is a Last Resort operation that only takes place when there is no other DP in the Numeration to satisfy the existing Theta Roles. Although it appears in a local relation to a Case assigning Probe [+T], the defective nature of PRO makes it unable to host a Case Value. By FI, the Chain of PRO collapses, in the sense of Martin (1996), with a local Chain. This derives the Control effect. The complementary distribution of NP-trace, PRO and lexical subjects correlates with the degree of defectiveness in the feature composition of T's in each instance. Raising T is Defective ([-T, -person]), Control T is Partial ([+T, -person]) and T in lexical subject licensing is Complete ([+T, +person]). Minimally, [+T] assigns Case to subjects (PRO/lexical). Complete Probes license lexical subjects, where [person] relates to the presence of C. The explanation of why lexical subjects and PRO are in complementary distribution is the following: by Minimality, Partial-T prevents the definition of a Binding Domain. Unlike PRO, lexical subjects need a Domain, and Partial-T does not provide one. Complete-T excludes PRO because Complete-T involves a CP Phase. In this context PRO lacks an antecedent with which to collapse and the Chain of PRO violates FI at LF.

This dissertation investigates the topic of verbal ellipsis in English. Two main issues are addressed in this work: (i) the identity condition that restricts the application of ellipsis and (ii) the different locality restrictions that apply to elliptical constructions. The identity condition is examined from the point of view of competence, while the locality condition is given a natural answer from the processing domain. Furthermore, a parsing algorithm based on minimalist grammars is defined. Chapter 1 introduces the topic. Chapter 2 and Chapter 3 deal with the syntactic identity condition. Chapter 2 reviews some proposals in the literature, namely, Lasnik (1995b), Kitagawa (1991) and Fiengo and May (1994). All these analyses examine controversial examples where, apparently, partial syntactic identity between antecedent and gap is found. Chapter 3 presents a new analysis which assumes late lexical insertion, in the spirit of derivational morphology (Marantz 1993), and offers a unified account of all the cases of partial identity introduced in the previous chapter. It is argued that syntactic identity must be respected, and that the crucial notion for ellipsis is identity of syntactic categoriesa condition that is met before lexical items are inserted. Also, the different readings that obtain under ellipsis (i.e., sloppy and strict readings) are explained as emerging at different points in the derivation: before and after lexical insertion, respectively. Chapter 4 reviews one proposal in the parsing literature (Lappin and McCord 1990) as well as the problems it faces. Chapter 5 offers a processing account of the locality restrictions on gapping (as opposed to VPE and Pseudogapping)), those are analyzed as a result of (i) tense absence/presence (Fodor 1985), (ii) low initial attachment of coordinates, and (iii) Spell-out operations which render syntactic structure unavailable (Uriagereka 1999). A two-fold ellipsis resolution process is presented herewhere some work is done on-line, but some at the LF level. Chapter 6 defines an algorithm based on minimalist grammar operations, precisely on the preference of Merge-over-Move-over-Spell-out (as defined by Weinberg 1999); thus, showing that minimalist grammar models can be translated into computational models. Chapter 7 presents the conclusions.

The general aim of this thesis is to provide support for the claim that movement can be driven by theta-features, advanced by Bokovič (1994), Hornstein (1999, 2001), Manzini and Russo (2000), and O'Neil (1997) among others, through a study of Japanese Psych Verb constructions that exhibit interesting peculiarities. In some psych verb constructions, theta-roles are projected in an order that diverges from the canonical order found in other dyadic constructions. The theme role of Object Experiencer (OE) verbs is realized in the subject position of the sentence, while the experiencer role is linked to the object position. On the other hand, Subject Experiencer (SE) verbs map the theme role to the object position while the experiencer role is realized in the subject position. Given that in general experiencers are mapped to the subject/external argument position, OE verb constructions raise some critical issues for the Principles and Parameters theory (Chomsky, 1981), in particular for the theories of argument structure. The first goal of the thesis is to provide a solution to this linking puzzle as well as other peculiarities of OE verbs in Minimalist terms. In particular, I claim that the subject of an OE verb sentence is derived by thematically driven movement. By allowing such movement, the inverse linking pattern, backward binding phenomenon, and scope patterns of OE verbs can be accounted for straightforwardly. The second goal is to investigate the structures of SE verbs and OE verbs and how they are related one another. I propose that an OE verb is a mono-clausal causative, composed of an SE verb base and a causative morpheme -sase, and that SE verbs are bare VPs without vP projection. This amounts to saying that SE verbs do not project the external argument. It is shown that SE verbs do not allow passivization, supporting the claim that SE verbs do not project the external argument.

Word Sense Disambiguation (WSD) is the process of resolving the meaning of a word unambiguously in a given natural language context. Within the scope of this thesis, it is the process of marking text with explicit sense labels. What constitutes a sense is a subject of great debate. An appealing perspective, aims to define senses in terms of their multilingual correspondences, an idea explored by several researchers, Dyvik (1998), Ide (1999), Resnik & Yarowsky (1999), and Chugur, Gonzalo & Verdejo (2002) but to date it has not been given any practical demonstration. This thesis is an empirical validation of these ideas of characterizing word meaning using cross-linguistic correspondences. The idea is that word meaning or word sense is quantifiable as much as it is uniquely translated in some language or set of languages. Consequently, we address the problem of WSD from a multilingual perspective; we expand the notion of context to encompass multilingual evidence. We devise a new approach to resolve word sense ambiguity in natural language, using a source of information that was never exploited on a large scale for WSD before. The core of the work presented builds on exploiting word correspondences across languages for sense distinction. In essence, it is a practical and functional implementation of a basic idea common to research interest in defining word meanings in cross-linguistic terms. We devise an algorithm, SALAAM for Sense Assignment Leveraging Alignment And Multilinguality, that empirically investigates the feasibility and the validity of utilizing translations for WSD. SALAAM is an unsupervised approach for word sense tagging of large amounts of text given a parallel corpus — texts in translation — and a sense inventory for one of the languages in the corpus. Using SALAAM, we obtain large amounts of sense annotated data in both languages of the parallel corpus, simultaneously. The quality of the tagging is rigorously evaluated for both languages of the corpora. The automatic unsupervised tagged data produced by SALAAM is further utilized to bootstrap a supervised learning WSD system, in essence, combining supervised and unsupervised approaches in an intelligent way to alleviate the resources acquisition bottleneck for supervised methods. Essentially, SALAAM is extended as an unsupervised approach for WSD within a learning framework; in many of the cases of the words disambiguated, SALAAM coupled with the machine learning system rivals the performance of a canonical supervised WSD system that relies on human tagged data for training. Realizing the fundamental role of similarity for SALAAM, we investigate different dimensions of semantic similarity as it applies to verbs since they are relatively more complex than nouns, which are the focus of the previous evaluations. We design a human judgment experiment to obtain human ratings on verbs’ semantic similarity. The obtained human ratings are cast as a reference point for comparing different automated similarity measures that crucially rely on various sources of information. Finally, a cognitively salient model integrating human judgments in SALAAM is proposed as a means of improving its performance on sense disambiguation for verbs in particular and other word types in general.

A dissertation on the syntax and comprehension of wh-dependencies.