UMD Theses and Dissertations
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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.
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Item GENERATING AND MEASURING PREDICTIONS IN LANGUAGE PROCESSING(2023) Nakamura, Masato; Philips, Colin; Linguistics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Humans can comprehend utterances quickly, efficiently, and often robustly against noise in the inputs. Researchers have argued that such a remarkable ability is supported by prediction of upcoming inputs. If people use the context to infer what they would hear/see and prepare for likely inputs, they should be able to efficiently process the predicted inputs.This thesis investigates how contexts can predictively activate lexical representations (lexical pre-activation). I address two different aspects of prediction: (i) how pre-activation is generated using contextual information and stored knowledge, and (ii) how pre-activation is reflected in different measures. I first assess the linking hypothesis of the speeded cloze task, a measure of pre-activation, through computational simulations. I demonstrate that an earlier model accounts for qualitative patterns of human data but fails to predict quantitative patterns. I argue that a model with an additional but reasonable assumption of lateral inhibition successfully explains these patterns. Building on the first study, I demonstrate that pre-activation measures fail to align with each other in cases called argument role reversals, even if the time courses and stimuli are carefully matched. The speeded cloze task shows that “role-appropriate” serve in ... which customer the waitress had served is more strongly pre-activated compared to the “role- inappropriate” serve in ... which waitress the customer had served. On the other hand, the N400 amplitude, which is another pre-activation measure, does not show contrasts be- tween the role-appropriate and inappropriate serve. Accounting for such a mismatch between measures in argument role reversals provides insights into whether and how argument roles constrain pre-activation as well as how different measures reflect pre-activation. Subsequent studies addressed whether pre-activation is sensitive to argument roles or not. Analyses of context-wise variability of role-inappropriate candidates suggest that there are some role-inappropriate pre-activations even in the speeded cloze task. The next study at- tempts to directly contrast pre-activations of role-appropriate and inappropriate candidates, eliminating the effect of later confounding processes by distributional analyses of reaction times. While one task suggests that role-appropriate candidates are more strongly pre- activated compared to the role-inappropriate candidates, the other task suggests that they have matched pre-activation. Finally, I examine the influence of role-appropriate competitors on role-inappropriate competitors. The analyses of speeded cloze data suggest that N400 amplitudes can be sensitive to argument roles when there are strong role-appropriate competitors. This finding can be explained by general role-insensitivity and partial role-sensitivity in pre-activation processes. Combined together, these studies suggest that pre-activation processes are generally insensitive to argument roles, but some role-sensitive mechanisms can cause role-sensitivity in pre-activation measures under some circumstances.Item The Psycho-logic of Universal Quantifiers(2021) Knowlton, Tyler Zarus; Lidz, Jeffrey; Linguistics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)A universally quantified sentence like every frog is green is standardly thought to express a two-place second-order relation (e.g., the set of frogs is a subset of the set of green things). This dissertation argues that as a psychological hypothesis about how speakers mentally represent universal quantifiers, this view is wrong in two respects. First, each, every, and all are not represented as two-place relations, but as one-place descriptions of how a predicate applies to a restricted domain (e.g., relative to the frogs, everything is green). Second, while every and all are represented in a second-order way that implicates a group, each is represented in a completely first-order way that does not involve grouping the satisfiers of a predicate together (e.g., relative to individual frogs, each one is green).These “psycho-logical” distinctions have consequences for how participants evaluate sentences like every circle is green in controlled settings. In particular, participants represent the extension of the determiner’s internal argument (the cir- cles), but not the extension of its external argument (the green things). Moreover, the cognitive system they use to represent the internal argument differs depend- ing on the determiner: Given every or all, participants show signatures of forming ensemble representations, but given each, they represent individual object-files. In addition to psychosemantic evidence, the proposed representations provide explanations for at least two semantic phenomena. The first is the “conservativity” universal: All determiners allow for duplicating their first argument in their second argument without a change in informational significance (e.g., every fish swims has the same truth-conditions as every fish is a fish that swims). This is a puzzling gen- eralization if determiners express two-place relations, but it is a logical consequence if they are devices for forming one-place restricted quantifiers. The second is that every, but not each, naturally invites certain kinds of generic interpretations (e.g., gravity acts on every/#each object). This asymmetry can po- tentially be explained by details of the interfacing cognitive systems (ensemble and object-file representations). And given that the difference leads to lower-level con- comitants in child-ambient speech (as revealed by a corpus investigation), children may be able to leverage it to acquire every’s second-order meaning. This case study on the universal quantifiers suggests that knowing the meaning of a word like every consists not just in understanding the informational contribu- tion that it makes, but in representing that contribution in a particular format. And much like phonological representations provide instructions to the motor plan- ning system, it supports the idea that meaning representations provide (sometimes surprisingly precise) instructions to conceptual systems.Item Relating lexical and syntactic processes in language: Bridging research in humans and machines(2018) Ettinger, Allyson; Phillips, Colin; Resnik, Philip; Linguistics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Potential to bridge research on language in humans and machines is substantial - as linguists and cognitive scientists apply scientific theory and methods to understand how language is processed and represented by humans, computer scientists apply computational methods to determine how to process and represent language in machines. The present work integrates approaches from each of these domains in order to tackle an issue of relevance for both: the nature of the relationship between low-level lexical processes and syntactically-driven interpretation processes. In the first part of the dissertation, this distinction between lexical and syntactic processes focuses on understanding asyntactic lexical effects in online sentence comprehension in humans, and the relationship of those effects to syntactically-driven interpretation processes. I draw on computational methods for simulating these lexical effects and their relationship to interpretation processes. In the latter part of the dissertation, the lexical/syntactic distinction is focused on the application of semantic composition to complex lexical content, for derivation of sentence meaning. For this work I draw on methodology from cognitive neuroscience and linguistics to analyze the capacity of natural language processing systems to do vector-based sentence composition, in order to improve the capacities of models to compose and represent sentence meaning.Item Toward a Psycholinguistic Model of Irony Comprehension(2018) Adler, Rachel Michelle; Novick, Jared M; Huang, Yi Ting; Neuroscience and Cognitive Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation examines how listeners reach pragmatic interpretations of irony in real-time. Over four experiments I addressed limitations of prior work by using fine-grained measures of time course, providing strong contexts to support ironic interpretations, and accounting for factors known to be important for other linguistic phenomena (e.g., frequency). Experiment 1 used a visual world eye-tracking paradigm to understand how comprehenders use context and frequency information to interpret irony. While there was an overall delay for ironic utterances compared to literal ones, the speed of interpretation was modulated by frequency. Participants interpreted frequent ironic criticisms (e.g., “fabulous chef” about a bad chef) more quickly than infrequent ironic compliments (e.g., “terrible chef” about a good chef). In Experiment 2A, I tested whether comprehending irony (i.e., drawing a pragmatic inference) differs from merely computing the opposite of an utterance. The results showed that frequency of interpretation (criticisms vs. compliments) did not influence processing speed or overall interpretations for opposites. Thus, processing irony involves more than simply evaluating the truth-value condition of an utterance (e.g., pragmatic inferences about the speaker’s intentions). This was corroborated by Experiment 2B, which showed that understanding irony involves drawing conclusions about speakers in a way that understanding opposites does not. Opposite speakers were considered weirder and more confusing than ironic speakers. Given the delay in reaching ironic interpretations (Exp. 1), Experiments 3 and 4 examined the cognitive mechanics that contribute to inhibiting a literal interpretation of an utterance and/or promoting an ironic one. Experiment 3 tested whether comprehending irony engages cognitive control to resolve among competing representations (literal vs. ironic). Results showed that hearing an ironic utterance engaged cognitive control, which then facilitated performance on a subsequent high-conflict Stroop trial. Thus, comprehenders experience conflict between the literal and ironic interpretations. In Experiment 4, however, irony interpretation was not facilitated by prior cognitive control engagement. This may reflect experimental limitations or late-arriving conflict. I end by presenting a model wherein access to the literal and ironic interpretations generates conflict that is resolved by cognitive control. In addition, frequency modulates cue strength and generates delays for infrequent ironic compliments.Item Language Science Meets Cognitive Science: Categorization and Adaptation(2017) Heffner, Christopher Cullen; Newman, Rochelle S; Idsardi, William J; Neuroscience and Cognitive Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Questions of domain-generality—the extent to which multiple cognitive functions are represented and processed in the same manner—are common topics of discussion in cognitive science, particularly within the realm of language. In the present dissertation, I examine the domain-specificity of two processes in speech perception: category learning and rate adaptation. With regard to category learning, I probed the acquisition of categories of German fricatives by English and German native speakers, finding a bias in both groups towards quicker acquisition of non-disjunctive categories than their disjunctive counterparts. However, a study using an analogous continuum of non-speech sounds, in this case spectrally-rotated musical instrument sounds, did not show such a bias, suggesting that at least some attributes of the phonetic category learning process are unique to speech. For rate adaptation, meanwhile, I first report a study examining rate adaptation in Modern Standard Arabic (MSA), where consonant length is a contrastive part of the phonology; that is, where words can be distinguished from one another by the length of the consonants that make them up. I found that changing the rate of the beginning of a sentence can lead a consonant towards the end of the sentence to change in its perceived duration; a short consonant can sound like a long one, and a long consonant can sound like a short one. An analogous experiment examined rate adaptation in event segmentation, where adaptation-like effects had not previously been explored, using recordings of an actor interacting with a touchscreen. I found that the perception of actions can also be affected by the rate of previously-occurring actions. Listeners adapt to the rate at the beginning of a series of actions when deciding what they saw last in that series of actions. This suggests that rate adaptation follows similar lines across both domains. All told, this dissertation leads to a picture of domain-specificity in which both domain-general and domain-specific processes can operate, with domain-specific processes can help scaffold the use of domain-general processing.Item Parsing, Generation and Grammar(2016) Momma, Shota Momma; Phillips, Colin; Linguistics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Humans use their grammatical knowledge in more than one way. On one hand, they use it to understand what others say. On the other hand, they use it to say what they want to convey to others (or to themselves). In either case, they need to assemble the structure of sentences in a systematic fashion, in accordance with the grammar of their language. Despite the fact that the structures that comprehenders and speakers assemble are systematic in an identical fashion (i.e., obey the same grammatical constraints), the two ‘modes’ of assembling sentence structures might or might not be performed by the same cognitive mechanisms. Currently, the field of psycholinguistics implicitly adopts the position that they are supported by different cognitive mechanisms, as evident from the fact that most psycholinguistic models seek to explain either comprehension or production phenomena. The potential existence of two independent cognitive systems underlying linguistic performance doubles the problem of linking the theory of linguistic knowledge and the theory of linguistic performance, making the integration of linguistics and psycholinguistic harder. This thesis thus aims to unify the structure building system in comprehension, i.e., parser, and the structure building system in production, i.e., generator, into one, so that the linking theory between knowledge and performance can also be unified into one. I will discuss and unify both existing and new data pertaining to how structures are assembled in understanding and speaking, and attempt to show that the unification between parsing and generation is at least a plausible research enterprise. In Chapter 1, I will discuss the previous and current views on how parsing and generation are related to each other. I will outline the challenges for the current view that the parser and the generator are the same cognitive mechanism. This single system view is discussed and evaluated in the rest of the chapters. In Chapter 2, I will present new experimental evidence suggesting that the grain size of the pre-compiled structural units (henceforth simply structural units) is rather small, contrary to some models of sentence production. In particular, I will show that the internal structure of the verb phrase in a ditransitive sentence (e.g., The chef is donating the book to the monk) is not specified at the onset of speech, but is specified before the first internal argument (the book) needs to be uttered. I will also show that this timing of structural processes with respect to the verb phrase structure is earlier than the lexical processes of verb internal arguments. These two results in concert show that the size of structure building units in sentence production is rather small, contrary to some models of sentence production, yet structural processes still precede lexical processes. I argue that this view of generation resembles the widely accepted model of parsing that utilizes both top-down and bottom-up structure building procedures. In Chapter 3, I will present new experimental evidence suggesting that the structural representation strongly constrains the subsequent lexical processes. In particular, I will show that conceptually similar lexical items interfere with each other only when they share the same syntactic category in sentence production. The mechanism that I call syntactic gating, will be proposed, and this mechanism characterizes how the structural and lexical processes interact in generation. I will present two Event Related Potential (ERP) experiments that show that the lexical retrieval in (predictive) comprehension is also constrained by syntactic categories. I will argue that the syntactic gating mechanism is operative both in parsing and generation, and that the interaction between structural and lexical processes in both parsing and generation can be characterized in the same fashion. In Chapter 4, I will present a series of experiments examining the timing at which verbs’ lexical representations are planned in sentence production. It will be shown that verbs are planned before the articulation of their internal arguments, regardless of the target language (Japanese or English) and regardless of the sentence type (active object-initial sentence in Japanese, passive sentences in English, and unaccusative sentences in English). I will discuss how this result sheds light on the notion of incrementality in generation. In Chapter 5, I will synthesize the experimental findings presented in this thesis and in previous research to address the challenges to the single system view I outlined in Chapter 1. I will then conclude by presenting a preliminary single system model that can potentially capture both the key sentence comprehension and sentence production data without assuming distinct mechanisms for each.Item The cognitive basis for encoding and navigating linguistic structure(2014) Parker, Daniel; Phillips, Colin; Linguistics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation is concerned with the cognitive mechanisms that are used to encode and navigate linguistic structure. Successful language understanding requires mechanisms for efficiently encoding and navigating linguistic structure in memory. The timing and accuracy of linguistic dependency formation provides valuable insights into the cognitive basis of these mechanisms. Recent research on linguistic dependency formation has revealed a profile of selective fallibility: some linguistic dependencies are rapidly and accurately implemented, but others are not, giving rise to "linguistic illusions". This profile is not expected under current models of grammar or language processing. The broad consensus, however, is that the profile of selective fallibility reflects dependency-based differences in memory access strategies, including the use of different retrieval mechanisms and the selective use of cues for different dependencies. In this dissertation, I argue that (i) the grain-size of variability is not dependency-type, and (ii) there is not a homogenous cause for linguistic illusions. Rather, I argue that the variability is a consequence of how the grammar interacts with general-purpose encoding and access mechanisms. To support this argument, I provide three types of evidence. First, I show how to "turn on" illusions for anaphor resolution, a phenomena that has resisted illusions in the past, reflecting a cue- combinatorics scheme that prioritizes structural information in memory retrieval. Second, I show how to "turn off" a robust illusion for negative polarity item (NPI) licensing, reflecting access to the internal computations during the encoding and interpretation of emerging semantic/pragmatic representations. Third, I provide computational simulations that derive both the presence and absence of the illusions from within the same memory architecture. These findings lead to a new conception of how we mentally encode and navigate structured linguistic representations.Item Structured Access in Sentence Comprehension(2011) Dillon, Brian William; Phillips, Colin; Linguistics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This thesis is concerned with the nature of memory access during the construction of long-distance dependencies in online sentence comprehension. In recent years, an intense focus on the computational challenges posed by long-distance dependencies has proven to be illuminating with respect to the characteristics of the architecture of the human sentence processor, suggesting a tight link between general memory access procedures and sentence processing routines (Lewis & Vasishth 2005; Lewis, Vasishth, & Van Dyke 2006; Wagers, Lau & Phillips 2009). The present thesis builds upon this line of research, and its primary aim is to motivate and defend the hypothesis that the parser accesses linguistic memory in an essentially structured fashion for certain long-distance dependencies. In order to make this case, I focus on the processing of reflexive and agreement dependencies, and ask whether or not non-structural information such as morphological features are used to gate memory access during syntactic comprehension. Evidence from eight experiments in a range of methodologies in English and Chinese is brought to bear on this question, providing arguments from interference effects and time-course effects that primarily syntactic information is used to access linguistic memory in the construction of certain long-distance dependencies. The experimental evidence for structured access is compatible with a variety of architectural assumptions about the parser, and I present one implementation of this idea in a parser based on the ACT-R memory architecture. In the context of such a content-addressable model of memory, the claim of structured access is equivalent to the claim that only syntactic cues are used to query memory. I argue that structured access reflects an optimal parsing strategy in the context of a noisy, interference-prone cognitive architecture: abstract structural cues are favored over lexical feature cues for certain structural dependencies in order to minimize memory interference in online processing.Item On The Way To Linguistic Representation: Neuromagnetic Evidence of Early Auditory Abstraction in the Perception of Speech and Pitch(2009) Monahan, Philip Joseph; Idsardi, William J; Poeppel, David E; Linguistics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The goal of this dissertation is to show that even at the earliest (non-invasive) recordable stages of auditory cortical processing, we find evidence that cortex is calculating abstract representations from the acoustic signal. Looking across two distinct domains (inferential pitch perception and vowel normalization), I present evidence demonstrating that the M100, an automatic evoked neuromagnetic component that localizes to primary auditory cortex is sensitive to abstract computations. The M100 typically responds to physical properties of the stimulus in auditory and speech perception and integrates only over the first 25 to 40 ms of stimulus onset, providing a reliable dependent measure that allows us to tap into early stages of auditory cortical processing. In Chapter 2, I briefly present the episodicist position on speech perception and discuss research indicating that the strongest episodicist position is untenable. I then review findings from the mismatch negativity literature, where proposals have been made that the MMN allows access into linguistic representations supported by auditory cortex. Finally, I conclude the Chapter with a discussion of the previous findings on the M100/N1. In Chapter 3, I present neuromagnetic data showing that the re-sponse properties of the M100 are sensitive to the missing fundamental component using well-controlled stimuli. These findings suggest that listeners are reconstructing the inferred pitch by 100 ms after stimulus onset. In Chapter 4, I propose a novel formant ratio algorithm in which the third formant (F3) is the normalizing factor. The goal of formant ratio proposals is to provide an explicit algorithm that successfully "eliminates" speaker-dependent acoustic variation of auditory vowel tokens. Results from two MEG experiments suggest that auditory cortex is sensitive to formant ratios and that the perceptual system shows heightened sensitivity to tokens located in more densely populated regions of the vowel space. In Chapter 5, I report MEG results that suggest early auditory cortical processing is sensitive to violations of a phonological constraint on sound sequencing, suggesting that listeners make highly specific, knowledge-based predictions about rather abstract anticipated properties of the upcoming speech signal and violations of these predictions are evident in early cortical processing.