Theses and Dissertations from UMD
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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 give thesis/dissertation in DRUM
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Item CORTICAL AND STRIATAL MECHANISMS OF VALUE-BASED DECISION-MAKING AND THEIR DISRUPTION IN ADDICTION(2022) Hadfield, Heather; Roesch, Matthew R; Neuroscience and Cognitive Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)For decisions both great and small, the brain utilizes an extensive network that integrates value assessment, reward prediction, and motivation to quickly and efficiently select the most beneficial option while minimizing aversive consequences for ourselves. Numerous psychiatric conditions, in particular drug addiction, can disrupt this network and impair decision-making behavior. It is therefore important to understand the neural underpinnings of decision-making and how neural activity and its associated behavior are disrupted by drugs of abuse. My dissertation will expand on current studies of this circuitry by examining epigenetic and neurophysiological mechanisms of value-based decision-making within two regions of the brain. In my final aim, I explore a new behavioral assay that may be used to study these and other regions relevant for value-based decision-making in the context of another complex behavior.In my first aim, I have recorded from single neurons in the rat dorsal lateral striatum (DLS) after overexpressing histone deacetylase 5 (HDAC5), an epigenetic enzyme implicated in incubation of craving, in the dorsal striatum (DS). In my second aim I used pharmacological lesion and single-neuron recording combined with cocaine self-administration techniques to study anterior insula, a region well-known for combining internal and external experience but largely under-studied in the context of higher cognitive processes. These studies were conducted while rats performed an odor-guided decision-making task in which the value of rewards were manipulated by either the delay to or the size of the reward across a series of trial blocks. I have found overexpression of HDAC5 in DS promoted inflexible, faster, and automatic behavior in the decision-making task while increasing DLS’s response to reward cues- similar to previous studies examining DLS activity and behavior after cocaine self-administration. In my studies of insula, I found recording from this region novel, global signals of reward value that seemed to reflect the overall structure of the behavioral task. Following cocaine-exposure, these signals were diminished while immediate rewards were over-represented on a trial-by-trial basis, leading to steeper discounting of delayed rewards. Additional studies lesioning this region promoted faster reaction times and increased goal-directed behavior. Together, these results provide insights into how drugs of abuse may impair behavioral flexibility and the tracking of long-term changes in reward from multiple mechanisms. However, it is still unknown how these changes in value assessment give rise to complex impairments of behavior. As a first step to addressing this issue, I used a new task to examine how chronic drug use- which disrupts both neural signals in the corticostriatal circuit and epigenetic enzymes- also impairs the complex ability to delay gratification. This final study replicated well-established findings of drug-induced reversal-learning impairment, but surprisingly did not alter decision-making. This collection of work demonstrates the complexity with which drug exposure alters neural circuitry and value-based decision-making, and additionally shows the importance of utilizing complex behavioral assays to explore the relationship between brain and behavior.Item Explaining Resilience to Peer Influence: The Role of Decision-Making(2020) Deitzer, Jessica; McGloin, Jean M; Criminology and Criminal Justice; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Researchers often discuss deviant peers as if they are a deterministic risk for an adolescent's own delinquency. There is a strong, consistent link between the two, especially in adolescence. Yet, some adolescents act counter to predictions and display resilience to deviant peer influence. Paternoster and Pogarsky’s (2009) concept of thoughtfully reflective decision-making (TRDM) may add to our understanding of resilience to deviant peer exposure; individuals who make slow, deliberate decisions may be more likely to avoid the pitfalls associated with deviant peers, perhaps by selecting out of deviant social networks. In this dissertation, I use longitudinal data from the PROSPER Peers project in the context of adolescents in rural schools to 1) identify and describe a group of youth that displays resilience to deviant peer influence and 2) investigate whether decision-making skills differentiate those who demonstrate resilience from those who do not. I leverage structural equation modeling (SEM) to examine the role of TRDM in fostering resilience to deviant peer influence. Specifically, I test whether TRDM moderates the impact of deviant peer exposure on resilience directly or indirectly, through prompting changes to the adolescents’ social networks. I estimate SEM models that test these relationships using interaction and multigroup models separately for each starting wave. I find evidence that TRDM promotes resilience to deviant peer influence across waves. My results also provide evidence of a nonlinear interaction between deviant peer exposure and TRDM, whereby TRDM is most protective for adolescents with a high degree (but not entirely) deviant peer group in for analyses starting in 6th or 7th grade. I do not find evidence of a consistent association between TRDM and a change in adolescents’ proportion of deviant peers at the next wave or any partial or full reduction to the direct impact of TRDM on resilience when including this indirect pathway. Thus, I conclude that TRDM does not appear to have an indirect impact on resilience through prompting prosocial change to adolescents’ friend groups. Finally, I discuss the limitations of my study, along with its implications for theory, practice, and future research.Item Grounding Judgment Phenomena in Memory: Examining the Role of Retrieval in the Estimation of Events(2018) Nguyen, Rosalind; Dougherty, Michael; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Suppose you were running late to work and had to decide which route to take that would give you the best chance of getting to work on time. How do you come up with the various routes to consider? How do you assess which route will give you the best chance of getting to work on time? In order to make that decision, you may think about all the prior routes you’ve taken and then evaluate each one with some probability of getting the desired outcome. On the surface, the act of generating choices and evaluating their likelihood may seem to have little in common. However, one may be surprised to learn that these processes are closely intertwined. The findings from this project suggest that judgments of likelihood may be constrained by one’s ability to retrieve from semantic memory. In experiment 1, we demonstrate that one’s general ability to retrieve from long-term memory (LTM) may play a critical role in judgments of likelihood and that the nature of the retrieval may relate differentially to different types of event estimation. In experiment 2, we assess different measurement models of memory and find that the type of relation between memory and judgment changes as the function of the type of memory model that one adopts. Finally, combined data across both experiments reveal that how the to-be-judged items are distributed plays a role in judgments and that retrieval ability, specifically, semantic memory, is predictive of probability judgments. Taken together, we argue that the ability to retrieve from LTM plays a critical role in judging the likelihood of an event occurring.Item Aspects of Online Reviews and their Effects on Consumer Decisions(2018) Watson, Jared Joseph; Kirmani, Amna; Pocheptsova Ghosh, Anastasiya; Business and Management: Marketing; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation examines different aspects of online reviews and their effects in consumer decisions. Online reviews are proliferating at a tremendous rate, with most consumers now stating that online reviews are the most important product attribute in online purchase decisions (BrightLocal 2017). As such, it is important to understand how various aspects of reviews affect consumers’ decisions, and outline the conditions by which some of these attributes may have conditional influences. To that end, we begin this dissertation by first investigating two numerical attributes of online reviews, average product ratings and review volumes. Furthermore, because online reviews are becoming such an influential tool, firms have begun to attempt exploiting consumers via fake reviews (Mayzlin, Dover, and Chevalier 2014; Luca and Zervas 2016). Thus, the second essay in this dissertation investigates how consumers respond when a website discloses that they have caught fake reviews being written for a specific brand. In Essay I, we investigate how average product ratings and review volumes influence consumers’ decisions when faced with a choice set in which there is no dominant option (i.e., when one option has a higher rating, but fewer reviews relative to another option). We argue that the diagnosticity (i.e., influence) of both average product ratings and review volumes are conditionally influenced by the other attribute, and as such, the choice between the higher-rated, fewer reviews option and lower-rated, more reviews option is dependent on the specific values of each attribute. While prior research has demonstrated the relative influence of both attributes, the findings are still debated (Floyd et al. 2014; You, Vadakkepatt, and Joshi 2015). By investigating the conditional effects of these attributes on choice, we help to rectify the divergent findings. We argue that average product ratings are inherently more diagnostic than review volumes due to the bound versus unbound nature of their scales, respectively. Whereas average product ratings have stable scale boundaries (e.g., one to five stars), review volumes do not (e.g., zero to infinity). As such, review volumes are more susceptible to relative comparisons made within the choice set. We demonstrate how the relative diagnosticity of these attributes are a function of the review volumes contained within the choice set, and how this ultimately governs choice. We conclude Essay I with the theoretical implications as well as a series of simulations demonstrating the practical implications for managers. In Essay II, we demonstrate the consequence of websites informing consumers that they have identified fake reviews for brands featured on their website. While a growing body of literature has investigated the characteristics of fake reviews (Mukherjee et al. 2013; Ott et al. 2013), as well as the firms which are likely to solicit them (Mayzlin, Dover, and Chevalier 2014; Luca and Zervas 2016), to the best of our knowledge, this is the first investigation into the effect of disclosing this information to consumers. While fake review alerts inform consumers that websites are monitoring the reviews for fraudulent information, we argue that the alerts also activate consumers’ persuasion knowledge (Friestad and Wright 1994), leading to attempts to correct for perceived biased information, as well as justice against the brand when it is the source of the fake reviews. We demonstrate that fake reviews lead consumers to not only attempt correction in their perception of the brand, but also in the information that they acquire (i.e., the reviews they read). Furthermore, we show that reducing consumers’ perceptions of inaccurate information attenuates their corrections. As such, this research holds relevance for website managers which provide reviews for their consumers. In both essays, we demonstrate the consequences of review information in consumers’ judgments and decisions. We argue that managers must carefully consider what information to provide consumers, and how to present it, in order to avoid biasing their consumers’ decisions.Item THE LONG-TERM IMPACT OF PREVIOUS COCAINE SELF-ADMINISTRATION ON DECISION-MAKING AND STRIATAL CIRCUITRY(2017) Burton, Amanda Claire; Roesch, Matthew R; Neuroscience and Cognitive Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Current theories of addiction suggest that impaired decision-making observed in individuals that chronically abuse drugs reflects a decrease in goal-directed behaviors and an increase in habitual behaviors governed by neural representations of response-outcome and stimulus-response associations, respectively. The striatum is a critical input component to the basal ganglia, which is a complex set of subcortical brain structures involved in the selection and execution of actions. Striatal sub-regions are some of the first brain regions to be affected by drugs of abuse, yet we still do not fully understand how decision-making and neural correlates in these regions are affected by drug exposure or disruptions within the circuit. My project was designed to study behavioral and neural changes in the striatum after previous cocaine self-administration or pharmacological lesion while rats perform a complex decision-making task. I therefore implemented a cocaine self-administration or pharmacological lesion protocol and recorded from single neurons in striatal sub-regions, specifically the nucleus accumbens core (NAc) and dorsal lateral striatum (DLS), during performance of an odor-guided decision-making task in which reward contingencies often changed. This task independently manipulated value of expected reward by changing the delay to or size of reward across a series of blocks of trials. I found that previous cocaine self-administration made rats more impulsive, biasing choice behavior toward more immediate reward. After cocaine exposure, there were fewer task-responsive neurons in the NAc and in those that remained we observed diminished directional and value encoding compared to controls. Surprisingly, in the DLS I found evidence of increased response-outcome associations and no evidence of enhanced stimulus-response associations after cocaine exposure. After disrupting communication between the NAc and DLS, I found evidence of enhanced stimulus-response associations in the DLS during task performance. This suggests that cocaine exposure impacts decision-making and neural activity in the striatum that manifests in more complex ways than simply disrupting striatal circuitry as current theories of addiction suggest.Item SCHOOL DISTRICT GOVERNANCE AND KNOWLEDGE-FIT IN DECISION RIGHTS: HOW DISTRICTS RECRUIT AND HIRE SCHOOL LIBRARIANS(2016) DiScala, Jeffrey Michael; Carlson Weeks, Ann; Butler, Brian S; Library & Information Services; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This study examines the organizational structures and decision-making processes used by school districts to recruit and hire school librarians. For students to acquire the information and technology literacy education they need, school libraries must be staffed with qualified individuals who can fulfill the librarian’s role as leader, teacher, instructional partner, information specialist, and program administrator. Principals are typically given decision rights for hiring staff, including school librarians. Research shows that principals have limited knowledge of the skills and abilities of the school librarian or the specific needs and functions of the library program. Research also indicates that those with specific knowledge of school library programs, namely school district library supervisors, are only consulted on recruiting and hiring about half the time. School districts entrust library supervisors with responsibilities such as professional development of school librarians only after they are hired. This study uses a theoretical lens from research on IT governance, which focuses on the use of knowledge-fit in applying decision rights in an organization. This framework is appropriate because of its incorporation of a specialist with a specific knowledge set in determining the placement of input and decision rights in the decision-making processes. The method used in this research was a multiple-case study design using five school districts as cases, varying by the involvement of the supervisors and other individuals in the hiring process. The data collected from each school district were interviews about the district’s recruiting and hiring practices with principals, an individual in HR, library supervisors, and recently hired school librarians. Data analysis was conducted through iterative coding from themes in the research questions, with continuous adjustments as new themes developed. Results from the study indicate that governance framework is applicable to evaluating the decision-making processes used in recruiting and hiring school librarians. However, a district’s use of governance did not consistently use knowledge-fit in the determination of input and decision rights. In the hiring process, governance was more likely to be based on placing decision rights at a certain level of the district hierarchy rather than the location of specific knowledge, most often resulting in site-based governance for decision rights at the school-building level. The governance of the recruiting process was most affected by the shortage or surplus of candidates available to the district to fill positions. Districts struggling with a shortage of candidates typically placed governance for the decision-making process on recruiting at the district level, giving the library supervisor more opportunity for input and collaboration with human resources. In districts that use site-based governance and that place all input and decision rights at the building level, some principals use their autonomy to eliminate the school library position in the allotment phase or hire librarians that, while certified through testing, do not have the same level of expertise as those who achieve certification through LIS programs. The principals in districts who use site-based governance for decision rights but call on the library supervisor for advisement stated how valuable they found the supervisor’s expertise in evaluating candidates for hire. In no district was a principal or school required to involve the library supervisor in the hiring of school librarians. With a better understanding of the tasks involved, the effect of district governance on decision-making, and the use of knowledge to assign input and decision rights, it is possible to look at how all of these factors affect the outcome in the quality of the hire. A next step is to look at the hiring process that school librarians went through and connect those with the measurable outcomes of hiring: school librarian success, retention, and attrition; the quality of school library program services, outreach, and involvement in a school; and the perceptions of the success of the school librarian and the library program as seen from students, teachers, administrators, parents, and other community stakeholders.Item The Evolving National Security Role of the Vice President(2014) Mannes, Aaron; Destler, I. M.; Public Policy; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)For most of U.S. history the vice president played little role in White House decision-making. In the 1970s this began to change. This dissertation uses a series of case studies of instances of vice presidential influence (with a focus on national security issues) to identify how and why the vice presidency has became an important presidential advisor. Gathering information through interviews and existing literature, this dissertation examines several factors that have facilitated the rise of the vice presidency including: the expansion of presidential power and responsibility, the institutional growth of the vice presidency in terms of staff and access, and the modern trend of "outsider" presidents who take office with little experience in Washington DC or national security affairs. The dissertation concludes by examining the factors that allow vice presidents to potentially exercise influence and the presidential needs that make vice presidential influence more or less likely.Item Enduring Dilemmas: Sources of American Ambivalence Toward European Defense Autonomy, The EDC and ESDP in Comparative Perspective(2005-08-04) Armitage, David T., Jr.; Quester, George H.; Government and Politics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Since World War II, transatlantic security relations have reflected a tension between American desires for Europeans to share more of the defense burden without having to give up its leadership role and European desires for greater defense autonomy without having to devote more resources toward military capabilities. The dissertation explores this tension and argues that systemic theories of international relations do not adequately explain why the US supported a potentially competitive institution with NATO - the European Defense Community (EDC) - during the 1950's, while resisting a much-looser version of European defense cooperation in European Security and Defense Policy (ESDP) in the late 1990's. The dissertation focuses on additional variables at the domestic level, such as fragmented political systems, divergent threat perceptions, and core beliefs and influence of policy entrepreneurs in explaining US behavior toward European defense ambitions during these two discrete periods of time.Item Senior Campus Administrators, Decision-Making and the Campus Racial Climate(2004-04-30) Ting, Marie P; Milem, Jeffrey F; Education Policy, and LeadershipThe purpose of this study was to understand senior administrative decision-making regarding the campus racial climate within institutions of higher education. Specifically, I addressed the following questions: 1. How do senior administrators learn/develop their views about diversity? 2. What is their experience with diverse populations and how does this influence their views about diversity? 3. What organizational characteristics of the University of Maryland influenced their decisions? 4. What common factors influence senior administrators decision-making regarding policies and practices related to the campus racial climate? To answer these questions, I engaged in an interpretive case study analysis (Merriam, 1998) of senior administrators at the University of Maryland. Data obtained from semi-structured interviews with fifteen senior administrators and documents were analyzed to create themes around how senior administrators make decisions regarding the campus racial climate. This study has implications for expanding theory, particularly regarding decision-making in higher education. In the most general sense, the data collected in this study was consistent with existing research on decision-making within institutions of higher education. In this study, decision-making regarding the campus racial climate was influenced both by individual differences and the organizational nature of institutions of higher education (Baldridge et al. 1979, 1991). This study also reinforced the research by Hurtado et al. (1998, 1999) showing that socio-historical forces, governmental policies and an institution's legacy of inclusion/exclusion, the psychological and behavioral climates affect the campus racial climate. Implications for practice suggests five propositions for consideration regarding the factors that influence the decision-making of administrators regarding the campus racial climate: 1) Race matters in decision-making, 2) Experiences that administrators have with diverse others, diverse ideas and diverse institutions affect the decisions they make regarding the campus racial climate, 3) The institutional context in which decisions are made matters a great deal, 4) Faculty members play an important role in shaping administrative decisions and how they are engaged and involved in diversity efforts is important, 5) Given the professional nature of higher education, leaders can shape the campus racial climate through the use of symbols.