COMMITMENT AND FLEXIBILITY IN THE DEVELOPING PARSER

This dissertation investigates adults and children's sentence processing mechanisms, with a special focus on how multiple levels of linguistic representation are incrementally computed in real time, and how this process affects the parser's ability to later revise its early commitments. Using cross-methodological and cross-linguistic investigations of long-distance dependency processing, this dissertation demonstrates how paying explicit attention to the procedures by which linguistic representations are computed is vital to understanding both adults' real time linguistic computation and children's reanalysis mechanisms. The first part of the dissertation uses time course evidence from self-paced reading and eye tracking studies (reading and visual world) to show that long-distance dependency processing can be decomposed into a sequence of syntactic and interpretive processes. First, the reading experiments provide evidence that suggests that filler-gap dependencies are constructed before verb information is accessed. Second, visual world experiments show that, in the absence of information that would allow hearers to predict verb content in advance, interpretive processes in filler-gap dependency computation take around 600ms. These results argue for a predictive model of sentence interpretation in which syntactic representations are computed in advance of interpretive processes. The second part of the dissertation capitalizes on this procedural account of filler-gap dependency processing, and reports cross-linguistic studies on children's long-distance dependency processing. Interpretation data from English and Japanese demonstrate that children actively associate a fronted wh-phrase with the first VP in the sentence, and successfully retract such active syntactic commitments when the lack of felicitous interpretation is signaled by verb information, but not when it is signaled by syntactic information. A comparison of the process of anaphor reconstruction in adults and children further suggests that verb-based thematic information is an effective revision cue for children. Finally, distributional analyses of wh-dependencies in child-directed speech are conducted to investigate how parsing constraints impact language acquisition. It is shown that the actual properties of the child parser can skew the input distribution, such that the effective distribution differs drastically from the input distribution seen from a researcher's perspective. This suggests that properties of developing perceptual mechanisms deserve more attention in language acquisition research

Reduced Left Lateralization of Language in Congenitally Blind Individuals

Language processing depends on a left-lateralized network of frontotemporal cortical regions. This network is remarkably consistent across individuals and cultures. However, there is also evidence that developmental factors, such as delayed exposure to language, can modify this network. Recently, it has been found that, in congenitally blind individuals, the typical frontotemporal language network expands to include parts of “visual” cortices. Here, we report that blindness is also associated with reduced left lateralization in frontotemporal language areas. We analyzed fMRI data from two samples of congenitally blind adults (n = 19 and n = 13) and one sample of congenitally blind children (n = 20). Laterality indices were computed for sentence comprehension relative to three different control conditions: solving math equations (Experiment 1), a memory task with nonwords (Experiment 2), and a “does this come next?” task with music (Experiment 3). Across experiments and participant samples, the frontotemporal language network was less left-lateralized in congenitally blind than in sighted individuals. Reduction in left lateralization was not related to Braille reading ability or amount of occipital plasticity. Notably, we observed a positive correlation between the lateralization of frontotemporal cortex and that of language-responsive occipital areas in blind individuals. Blind individuals with right-lateralized language responses in frontotemporal cortices also had right-lateralized occipital responses to language. Together, these results reveal a modified neurobiology of language in blindness. Our findings suggest that, despite its usual consistency across people, the neurobiology of language can be modified by nonlinguistic experiences

Working memory and relative clause attachment in first and second language processing

Thesis (M.A.)--University of Hawaii at Manoa, 2005.Includes bibliographical references (leaves 179-190).xvi, 190 leaves, bound 29 c

Syntactic production is not independent of inhibitory control: Evidence from agreement attraction errors

Native adult speakers of a language can produce grammatical sentences fluently, effortlessly, and with relatively few errors. These characteristics make the highly-practiced task of speaking a viable candidate for an automatic process, i.e., one independent of cognitive control. However, recent studies have suggested that some aspects of production, such as lexical retrieval and tailoring speech to an addressee, may depend on the speaker’s inhibitory control abilities. Less clear is the dependence of syntactic operations on inhibitory control processes. Using both a direct manipulation of inhibitory control demands and an analysis of individual differences, we show that one of the most common syntactic operations, producing the correct subject-verb agreement, requires inhibitory control when a singular subject noun competes with a plural local noun as in “The snake next to the purple elephants is green.” This finding calls for the integration of inhibitory control mechanisms into models of agreement production, and more generally into theories of syntactic production

Revisiting Agreement: Do Children and Adults Compute Subject-verb Agreement Differently?

Adult speakers rarely produce a verb that does not agree with its subject in number, unless the sentence contains nouns with clashing pluralities. For example, a sentence such as “The key next to the cabinets…”, sometimes elicits a plural verb, and such attraction errors are more common with singular than plural heads (the attraction asymmetry). Both attraction and attraction asymmetry have been instrumental in understanding the computations underlying agreement production. Interestingly, developmental studies of agreement have often found very different patterns of agreement errors in children, leading to the conclusion of different mechanisms for agreement production in children and adults. Using a referential communication game, we demonstrate that English-speaking children as young as 5 years of age show robust agreement attraction. Children 6 years and older also demonstrate the attraction asymmetry. These findings support similar mechanisms underlying agreement production in children and adults

Developmental changes in misinterpretation of garden-path wh-questions in French

This study explores (mis) interpretation of bi clausal wh-questions by French-speaking adults and children, aiming to investigate cross-linguistic differences in sentence revision mechanisms. Following previous work in Japanese the ambiguity of wh-questions was manipulated: In ambiguous questions, the fronted wh-phrase could be associated with the first, main-clause verb or the second, embedded-clause verb, while in garden-path questions, an inserted filled-gap prepositional phrase (PP) blocked main-clause attachment. Importantly, French differs from Japanese in that the filled gap arises after the first verb —that is, after the wh- phrase has been interpreted within the main clause. Two story-based comprehension experiments were conducted to probe the effect of word order on revision performance. Adults and children frequently provided main -clause interpretations of ambiguous questions. In filled-gap questions, children displayed relatively acute sensitivity to the filled-gap in wh-argument questions (Experiment2), but not in wh-adjunct questions(Experiment1); adults showed surprisingly low sensitivity to it, frequently misinterpreting adjunct and argument questions. Acceptability rating, (Experiment3) showed that adults systematically prefer in situ questions over wh-fronting questions. We conclude that timing of the error signal influences revision, and that whereas French-speaking children prioritize syntactic cues, adults prioritize distributional information about the optionality of wh-fronting in French

Revisiting Subject-Object Asymmetry: Subextraction in Japanese

Linguistic