<p> Category-specific semantic deficits (CSSD) result in the inability to recognize, recall, and/or remember objects from a particular semantic category. There is a common pattern of impairments observed in CSSD patients that is reviewed in Section One. In Section Two, I used a tempo-matching speeded word verification task to investigate the early stages of semantic memory to examine the similarities between healthy participants under time pressure and the patient data. Specifically, I sought to produce in the latter the reversal of the basic level effect found in CSSD, and to examine healthy participant data for other CSSD trends. The speeded methodology generally failed to replicate the reversal of the basic level effect, except for several specific items at the shortest response deadline. The final study in Section Two examines the effect of semantic relatedness on this task. Three types of semantic relatedness each reduced the speed and accuracy of responses relative to unrelated conditions. Section Three provides an overview and discussion of the results. The failure to replicate the reversal of the basic level effect suggests that speeded classification of neuropsychologically relevant stimuli does not share a common etiology with CSSD.</p>

<p> This investigation explores the potential effect on perception of speech visual cues associated with Arabic gutturals (AGs) and Arabic emphatics (AEs); AEs are pharyngealized phonemes characterized by a visually salient primary articulation but a rather invisible secondary articulation produced deep in the pharynx. The corpus consisted of 72 minimal pairs each containing two contrasting consonants of interest (COIs), an emphatic versus a non-emphatic, or a guttural paired with another guttural. In order to assess the potential effect that visual speech information in the lips, chin, cheeks, and neck has on the perception of the COIs, production data elicited from 4 native Lebanese speakers was captured on videos that were edited to allow perceivers to see only certain regions of the face. Fifty three Lebanese perceivers watched the muted movies each presented with a minimal pair containing the word uttered in the video, and selected in a forced identification task the word they thought they saw the speaker say.</p><p> The speakers&rsquo; speech was analyzed to help explore what in their production informed correct identification of the COIs. Perceivers were above chance at correctly identifying AEs and AGs, though AEs were better perceived than AGs. In the emphatic category, the effect on perception of measurement differences between a word and its pair was submitted to automatic speech recognition. The machine learning models were generally successful at correctly classifying COIs as emphatic or non-emphatics across vowel contexts; the models were able to predict the probability of perceivers&rsquo; accuracy in identifying certain COIs produced by certain speakers; also, an overlap between the measurements selected by the computer and those selected by human perceivers was found. No difference in perception of AEs according to the part of the face that was visible was observed, suggesting that the lips, present in all of the videos, were most important for perception of emphasis. Conversely, in the perception of AGs, lips were not as informative and perceivers relied more on cheeks and chin. The presence of visible cues associated with the AEs, particularly in the lips, suggests that such visual cues might be informative for non-native learners as well, if they were trained to attend to them.</p>

Thesis (Ph.D.)--Indiana University, Dept. of Linguistics and the Program in Cognitive Science, 2007. / Title from PDF t.p. (viewed Nov. 20, 2008). Source: Dissertation Abstracts International, Volume: 68-03, Section: A, page: 0982. Advisers: Michael Gasser; Michael N. Jones.

Thesis (Ph.D.)--Indiana University, Dept. of Psychological and Brain Sciences and Program in Neuroscience, 2007. / Title from dissertation home page (viewed Sept. 29, 2008). Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 1354. Adviser: Robert Goldstone.

<p> The primary goal of this dissertation is to characterize the relative strength of two of the influences on the parser&rsquo;s behavior during ambiguity resolution: coreference dependency formation and verb frame preference. I find that coreference dependency formation exerts a stronger influence on the parser than does verb frame preference, even when verb frame preference is maximized in transitively biased frames. </p><p> Previous studies have shown local attachment bias initially directs the parser to an embedded object analysis in sentences like (1), in which the DP <i>Annie&rsquo;s melody</i> is locally ambiguous between the embedded object (EO)/matrix subject (MS) analyses (Ferreira and Henderson, 1990). </p><p> (1) Whenever she was trying to casually hum Annie&rsquo;s melody was beautiful. </p><p> Additionally, (1) contains a cataphoric pronoun <i> she</i> which triggers an active search for an antecedent, whereby the parser seeks the antecedent only in grammatically sanctioned positions, such as where the antecedent is not c-commanded by the pronoun (Kazanina et al., 2007; van Gompel and Liversedge, 2003). In (1), the closest potential antecedent is <i>Annie.</i> However, it can be the antecedent only if the DP that contains it is analyzed as the MS, thus outside the whenever-clause and not c-commanded by <i>she.</i> A bias toward an early cataphoric dependency formation could lead the parser to analyze the ambiguous DP as the MS. In (1), there is a bias toward a MS analysis from the antecedent search in addition to a bias toward the local attachment EO analysis. </p><p> I find that, regardless of the transitivity bias of the verb in the position of <i>hums,</i> the parser forms a dependency between the pronoun <i> she</i> and <i>Annie.</i> This indicates that dependency formation can supersede verb frame preferences and any default preference the parser may have toward local attachment (Phillips and Gibson, 1997). Moreover, I also observe effects attributable to both the MS and EO parses. This suggests that the parser builds both alternatives and maintains them in parallel. From this, I conclude that the parser prioritizes information from an ongoing dependency search over lexical properties during ambiguity resolution.</p>

This dissertation investigates how knowledge of phonological generalizations influences speech perception, with a particular focus on evidence that phonological processing is autonomous from (rather than interactive with) auditory processing. A model is proposed in which auditory cue constraints and markedness constraints interact to determine a surface representation, which is taken to be isomorphic to the listener's perceptual response under some psychophysical conditions. Constraint ranking is argued to be stochastic in this model on the basis that the probability of computing the least marked surface representation (and perceptual response) is greater when the input auditory representation is ambiguous between two alternative categories than when it strongly favors a category that completes a more marked surface representation (and perceptual response). Experimental evidence is presented to demonstrate that (1) native listeners of languages with assimilation processes confuse unassimilated and assimilated sequences when discrimination is category-based (but not when discrimination is based on auditory representations), (2) German listeners use phonological context to anticipate the presence of a following allophone iff it is the allophone with broader distribution, and (3) that non-rhotic English listeners perceptually epenthesize and delete /r/ and they also may perceptually undo /r/ deletion. (1) suggests that knowledge of a phonological generalization may be applied only after auditory processing, which is a result consistent with the predictions of 'autonomous theory' and inconsistent with the predictions of 'interactive theory'. (2) and (3) show that phonological effects in speech perception go beyond biases against illicit sequences and lead to the novel proposals that positive constraints (2) and opposite faithfulness constraints (3) exist in the perceptual grammar.

This dissertation examines comparative constructions, both in terms of their representation in syntax and semantics and in terms of the way these representations are built and interpreted incrementally during sentence processing. While there has been extensive investigation of comparatives in the syntax and semantics literature (see Bresnan, 1973; von Stechow, 1984; Heim, 1985; Kennedy, 1999, among others), there has been little work on how comparatives are processed (although see Fults and Phillips, 2004; Wellwood et al., 2009 for work on so-called comparative illusions). In the first half of the dissertation, I address issues that are primarily syntactic in nature; in the second half, I address issues that are primarily at the semantic and pragmatic levels. In Chapter 2, I examine the basic syntax of English comparatives and readers' expectations for the structure of comparatives during parsing. I present evidence from eye movements during reading to argue that a curious pattern of acceptability in comparatives (observed by Osborne, 2009) arises from processing factors rather than the grammar. Chapter 3 provides evidence from self-paced reading that, in contrast to what has been shown for other more widely studied structures, in comparative clauses subject gaps are more difficult to process than object gaps. Some potential accounts for this asymmetry between comparatives and other structures are discussed, and in Chapter 4, I argue for a grammar-based account of the subject gap penalty. Chapters 5 and 6 investigate questions in the semantics/pragmatics and semantic processing of comparatives. In Chapter 5, I introduce a previously unstudied type of comparative, which I call subset comparatives, and investigate their appropriate formal representation. In addition to their theoretical interest, subset comparatives can provide insight into comprehenders' expectations regarding the relationship between the two sets of entities involved in comparatives. Evidence from eye movement studies suggests that readers have an initial preference for contrast, or disjointness, between sets in comparatives. Chapter 6 investigates issues in the comparison of pluralities during on-line sentence processing, again as studied through eye movements during reading. This chapter provides evidence that, when comparing sets, comparisons that involve degrees along an adjectival scale involve complexity beyond that involved in comparing sets in terms of their cardinalities. The results of my experimental studies on comparatives are related to broader issues in linguistics and psycholinguistics, such as the sources of well-formedness (or ill-formedness) in language, the representation of linguistically described sets in language processing, and the interaction between levels of information (syntactic, semantic, and conceptual/world knowledge) in comprehension.

<p> The use of language is one of the defining features of human cognition. Focusing here on two key features of language, <i>productivity</i> and <i>robustness</i>, I examine how basic questions regarding linguistic representation can be approached with the help of probabilistic generative language models, or PGLMs. These statistical models, which capture aspects of linguistic structure in terms of distributions over events, can serve as both the product of language learning and as prior knowledge in real-time language processing. In the first two chapters, I show how PGLMs can be used to make inferences about the nature of people's linguistic representations. In Chapter 1, I look at the representations of language learners, tracing the earliest evidence for a noun category in large developmental corpora. In Chapter 2, I evaluate broad-coverage language models reflecting contrasting assumptions about the information sources and abstractions used for in-context spoken word recognition in their ability to capture people's behavior in a large online game of &ldquo;Telephone.&rdquo; In Chapter 3, I show how these models can be used to examine the properties of lexicons. I use a measure derived from a probabilistic generative model of word structure to provide a novel interpretation of a longstanding linguistic universal, motivating it in terms of cognitive pressures that arise from communication. I conclude by considering the prospects for a unified, expectations-oriented account of language processing and first language learning.</p><p>

Thesis (Ph.D.)--Indiana University, Dept. of Computer Science and the Dept. of Cognitive Science, 2008. / Title from PDF t.p. (viewed on May 13, 2009). Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 5071. Advisers: Mike Gasser; Lisa Gershkoff-Stowe.