UMD Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/3
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.
More information is available at Theses and Dissertations at University of Maryland Libraries.
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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 Communication and Social Influences on Foraging in Bats(2012) Wright, Genevieve Spanjer; Wilkinson, Gerald S; Moss, Cynthia F; Biology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Using social information can be an efficient way to respond to changing situations or to learn skills. Other benefits of foraging in a group, such as social facilitation, have also been reported. Furthermore, individuals foraging near conspecifics may use acoustic communication to mediate interactions. Many bat species (Order Chiroptera) are gregarious, and many tropical frugivorous bats rely on seasonally-abundant foods such that following conspecifics to a food source could benefit "followers" without harming "leaders." Animal-eating bats do not typically share food, but information obtained from experienced foragers could help facilitate development of prey acquisition skills in young bats. Additionally, communicative vocalizations serving various social functions have been reported in diverse bat species. Despite the opportunities for social learning and information transfer that many bats experience, few studies have attempted to determine if these phenomena occur in bats. Similarly, despite research on echolocation and some communicative calls, the context and function of social calls emitted by flying, foraging bats have received relatively little study. In this dissertation, I examine interactions between individuals in a foraging context and the impact of these interactions on the individuals' behavior. Specifically, I used pairs of big brown bats (Eptesicus fuscus) to test whether insectivorous bats can acquire a new foraging skill via social learning and what social cues might facilitate learning. I then describe the context of and attribute function to social calls emitted by bats in pairs. Finally, I examine the effects of social context on the foraging behavior of the frugivorous short-tailed fruit bat (Carollia perspicillata) presented with a food-finding task. My results provide the first evidence of the role of social learning (via attention to feeding buzzes and interaction with experienced individuals) in the development of foraging skills in young insectivorous bats. I also report a repertoire of social calls produced by foraging big brown bats and present evidence that males use social calls to defend food and increase their foraging success. Finally, I present evidence that social facilitation increases foraging performance in short-tailed fruit bats. These findings contribute to our knowledge of the social aspects of foraging in group-living animals.Item Development, Technology Adoption, and Social Networks(2011) Vasilaky, Kathryn Nadine; Vasilaky, Kathryn Nadine; Agricultural and Resource Economics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Agriculture remains a key component of economic development, but the methodology for how development policies are determined has changed for developing countries. In the last decade, the focus of economic growth in developing countries has shifted from country-wide prescriptions to testable micro-development programs at the local level. As international development focuses in on local programs, social networks have been identified as a key component for their effective deployment. This dissertation analyzes the effects of a social network-based intervention. It contributes to the economics literature on identifying social network effects by implementing a randomized encouragement design to develop social capital, while simultaneously introducing a new method of development training. The program implemented here is comprised of two parts, and was conducted with female-headed households in rural Uganda, that were growing a relatively new cash crop, cotton. The first part conducted social network-based information games in 20 sample villages, in which each participant was trained in one aspect of cultivating cotton, and encouraged to attain a full set of knowledge on growing cotton through her assigned learning networks. They were presented with two different incentives schemes for accumulating information: competitive and team incentives. The second portion of the program paired the surveyed individuals at random with other game participants. These pairs were encouraged to develop team goals across the growing season and a time schedule for networking as well as update and share their learned information from the games on a regular basis. The estimated effects of the SNI, which comprise this dissertation, include both the effects from the information games and the effects of the mentored pairing; that is, the impact of acquiring one information point and one new link. I compare the effects of this program to a standard agricultural training program that was concurrently conducted during this research, in which extension agents taught the same information that was presented in the information games but with a traditional classroom-based teaching method. My games analysis shows that females learn more when presented with competitive incentives. The total number of learning points learned during competitive incentives first order stochastically dominates the total number of learning points learned during team incentives. However, for the dissemination of one specific information point, team incentives are better at ensuring that a unique information point reaches the entire group. Difference in difference estimates, controlling for the training program, show that the overall SNI program had significant effects on the average farmer, with diminishing returns for higher yielding farmers. I find that these average effects are comparable to the effects of the conventional training program, but at a fifth of the implementation cost. A closer examination shows that the SNI program has its most significant effect for farmers growing around the average output when the program was started in 2009 (100-200 kgs/acre), while the Training program has its greatest and most significant impact for those yielding above the average output in 2009. Therefore, the two programs are not necessarily substitutes in how they effect change. My research shows that a competitive incentive structure coupled with social network-based learning serves as an effective paradigm for improving outcomes for the poorest producers.Item IS GRADE SPAN ASSOCIATED WITH THE LEVEL OF PROBLEM BEHAVIOR AMONG EIGHTH GRADERS? AN EXPLORATORY INVESTIGATION(2004-12-03) Rasmussen, Gina Ann; Gottfredson, Denise; Criminology and Criminal Justice; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)In spite of two waves of grade reorganization in American schoolsthe Junior High and Middle School movementsand the increase of problem behavior in schools, little empirical evidence exists pertaining to the effects of grade spanthe range of grades making up schoolson adolescent problem behavior. Utilizing a nationally representative sample that estimates the amount of problem behavior in and around schools, the present study employs a series of multiple regression analyses to examine the influence of grade span, and several control variables, on eighth-grade student problem behavior. Focusing on social learning theory, it is hypothesized that eighth graders who attend schools with older adolescents have more problem behavior than those who do not. Positive peer association is hypothesized to mediate the effect. Results revealed no effects between grade span and problem behavior. However, due to data limitations further research is recommended. Reasons for no effects are discussed.