College of Behavioral & Social Sciences
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The collections in this community comprise faculty research works, as well as graduate theses and dissertations..
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Item Assessing the Impact of Typical Variations in Stressful Life Events on Hippocampal Development in Childhood(2021) Botdorf, Morgan; Riggins, Tracy; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The negative impact of extreme stress on early brain development is well-documented. An emerging body of work suggests that less extreme and more typical variations in stressful experiences (e.g., parental divorce, changing schools) may also exert an impact on the brain, especially in early childhood; however, more systematic research is needed. Across, three studies, this dissertation addressed this gap by exploring effects of typical variations in stressful life events on development of the hippocampus, a brain region highly susceptible to stress. Study 1a assessed the impact of stressful life events on the development of hippocampal subfield volumes (i.e., CA1, CA2-4/dentate gyrus (DG), subiculum) in an accelerated longitudinal sample of 102 4- or 6-year-old children who were each followed for 3 years. Analyses revealed that experiencing more stressful life events was related to smaller CA1 and CA2-4/DG volumes in the 6- (but not 4-) year-old cohort. Study 1b used the same sample described in Study 1a to investigate the impact of stressful life events on functional connectivity between the hippocampus and stress-related cortical regions. Analyses revealed a significant association in the 4- (but not 6-) year-old cohort, such that experiencing more stressful life events was related to greater connectivity between the hippocampus and the insula, a region important for emotional processing. Study 2 assessed moderating effects of sex and socioeconomic status (SES) on the association between stressful events and hippocampal subfield volumes using a large (n = 4,348), diverse subsample of 9-10-year-old adolescents from the Adolescent Brain and Cognitive Development Study. Analyses revealed that stressful life events were related to smaller subiculum volumes, but these associations did not vary by sex or SES. Overall, these findings provide evidence of the impact of typical variations in stressful life events on both hippocampal structure and functional connectivity. Findings also highlight the complexity of stress effects on the brain as these experiences may impact the hippocampus in an age-dependent manner. These results advance our current understanding of how stress influences hippocampal development and pave the way for studies to assess the implications of findings both for cognitive processes and the development of stress-related disorders.Item Development of the Episodic Memory Network in Early Childhood: Insights from Graph Theoretical Analysis(2019) Botdorf, Morgan Anna; Riggins, Tracy; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The hippocampal memory network has been identified in both children and adults and shown to be related to episodic memory ability. However, it remains unclear how its organization may differ across development, particularly during periods of large behavioral gains in memory ability. The goal of the present study was to utilize graph theoretical analysis to investigate the integration of the hippocampus within the memory network and segregation from other networks (i.e., fronto-parietal and cingulo-opercular attention networks) in the brain. Results indicated that with age, there was a general increase in connections between the hippocampus and both regions within the memory network and regions in other networks in the brain. These differences may contribute to improvements in memory typically observed in early childhood. Future analyses will examine relations with memory behavior and probe whether segregation is observed using other metrics, a sample of adult data, or other networks (e.g., sensorimotor).Item Childhood Events and Long-Term Consequences(2015) Palloni, Giordano; Galiani, Sebastian; Economics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Health and experiences in early childhood are strongly associated with adult outcomes. In this dissertation, I explore the association in detail with a focus on identifying the causal mechanisms that generate variation in early health and uncovering the parental behaviors that determine whether early health and living conditions evolve into long-term deficits or advantages. In chapter 1, I explore whether pre-conception maternal desire for children of a particular sex has implications for the health of children in Indonesia. I show that a simple fertility stopping model predicts that when a child is born of the mother’s preferred sex, they will receive more resources, and I test this prediction empirically using a longitudinal data set. I find that children born of the mother’s preferred sex are heavier, have a higher body mass index, and experience fewer illnesses. I provide evidence that reductions in subsequent fertility are the primary mechanism for these effects. The existing research measuring the long-term implications of early childhood conditions frequently fails to identify the mechanisms through which early deficits become life-long disadvantages. In chapter 2, I examine one instance where deficits may matter for long-term well-being. Using data from Indonesia, I find that when third trimester rainfall is fifty percent higher than expected, birth weight and relative size are approximately .23 standard deviations higher. Despite this early advantage, I find no persistent positive impact fifteen years later. However, parental investment appears to be negatively influenced by in utero exposure to rainfall, suggesting that parents compensate for early health conditions. To date, research on the long-term effects of childhood participation in subsidized housing has been limited by the lack of suitable identification strategies and appropriate data. In chapter 3, I, along with my co-authors, create a new, national-level longitudinal data set on housing assistance and labor market earnings to explore how children’s housing affects their later employment and earnings. We find that while naïve estimates suggest there are substantial negative consequences to childhood participation in subsidized housing, household fixed-effects specifications attenuate these negative relationships for some demographic groups and uncover positive and significant effects for others.Item Development of subjective and objective recollection: Evidence from event-related potentials(2014) Rollins, Leslie Ann Hainley; Riggins, Tracy; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Memory, particularly memory for contextual details (i.e., recollection), undergoes significant development from middle childhood to young adulthood. This research examined the development of recollection utilizing participant's subjective reports as well as their objective accuracy for two contextual details (i.e., the color of the item and a semantic judgment made during encoding). The aims of the present studies were to examine age-related differences in subjective and objective recollection, the correspondence between these abilities, and their neural correlates. Participants included 6- to 8-year-old children, 12- to 13-year-old adolescents, and young adults. Event-related potentials (ERPs) were recorded during the encoding (Study 1) and retrieval (Study 2) portions of a memory paradigm. Age-related improvements in objective and subjective recollection were found in both studies. At encoding, ERP indices of recollection were present when recollection was indexed subjectively or by accuracy for the semantic judgment made during encoding. In contrast, ERP responses were not sensitive to recollection when memory for color was used as the measure of recollection. ERP effects associated with recollection at encoding were not influenced by age. This finding suggests that children, adolescents, and adults process items similarly at the encoding stage. During retrieval, a recollection effect was only present when recollection was indexed by subjective judgments. Further, this effect was influenced by participant age. The effect was absent in children, topographically widespread in adolescents, and, consistent with previous literature (for review see Rugg & Curran, 2007), maximal over left centro-parietal leads in adults. Collectively, these findings suggest that ERP effects associated with recollection may be more apparent using subjective versus objective measures and that improvement in memory performance from middle childhood to adulthood is primarily attributable to the development of consolidation, storage, or retrieval processes.Item Exploring the Impact of Neighborhood on State-Building in sub-Saharan Africa(2013) Garcia, David; Reed, William L; Government and Politics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Why is state-building more advanced in some sub-Saharan African countries than in others? And, over time, what accounts for the steady gains, steady declines, or gains followed by declines (or vice-versa) observed in the state-building trajectories of Africa's states? This dissertation endeavors to shed light on these questions by assessing the impact of one suspected cause of state-building variation: the way power is distributed among states and their neighbors. Specifically, this dissertation assesses whether the relative distribution of power provides incentives or disincentives to regimes in charge of states to pursue policies that are conducive or detrimental to state-building. Employing OLS, two hypotheses are tested: one which predicts that regimes in charge of relatively weak states promote policies conducive to state-building, and another which predicts that regimes in charge of relatively weak states opt for a strategy of personal rule that runs counter to the imperatives of state-building. Findings are mixed and often contingent upon how state-building is measured; when state-building is assessed in terms of how proficiently the state regulates social and economic life, provides infrastructure services to its population, and promotes human development, support is found for the latter hypothesis. Yet when state-building is measured in terms of how well the state monopolizes the legitimate use of force or forges convergence between nations and the state, no statistically significant relationship in either direction is found. Thus, while there is at least some evidence that the regional distribution of power impacts the state-building process, it does not appear to do so quite as robustly as expected.Item INFLUENCE OF EXECUTIVE FUNCTIONING ON MEMORY FOR CONTEXTUAL DETAILS AND FALSE RECOGNITION(2012) Rollins, Leslie Ann Hainley; Riggins, Tracy; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)No previous studies had examined how all constructs of executive functioning (i.e., conflict inhibition, delay inhibition, cognitive flexibility, and working memory) relate to memory for contextual details and false recognition in early childhood controlling for general intelligence. Three and six-year-old children performed a laboratory-based episodic memory task and a battery of neuropsychological tasks. The relation between executive functioning and false recognition was diminished taking general intellectual ability into account. Executive functioning did not predict memory for contextual details in the full sample. However, when children who were at chance at recalling contextual details were excluded from analysis, executive functioning showed a trend for accounting for variance beyond age group and general intellectual ability. The inability of this effect to reach conventional statistical significance was likely due low statistical power resulting from the sample size reduction. Specifically, accuracy on the day/night task, a measure of conflict inhibition, was a significant predictor.Item Health, Agriculture and Labor Markets in Developing Countries(2010) Kim, Yeon Soo; Cropper, Maureen; Lafortune, Jeanne; Economics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Rural households comprise a large share of the population in developing countries. This dissertation examines how the welfare of these households, whose economic activity mainly relies on agriculture, is affected by weather shocks and health shocks in the context of West Africa and Vietnam. In the second chapter of the dissertation, I use the variation in rainfall within and across years at a detailed geographic level in West Africa to examine how rainfall shocks might affect the well-being of very young children. Variations in rainfall may affect not only income, but also the opportunity cost of time of parents, which may negatively impact child welfare. I find that high long-term rainfall averages for a particular location and month increase the probability of giving birth in the dry season, whereas positive deviations from this long-term mean ("rainfall shocks") have a small but statistically significant negative effect on the probability of giving birth in the rainy season. Further, contrary to what one might expect, rainfall shocks do not appear to improve the survival chances of young children and shocks in the first year of life have an adverse effect on the survival of children that are born in the rainy season. This result may be partly attributable to the finding that rainfall shocks significantly reduce the time mothers breastfeed their children, which could be due to a trade-off with work. Breastfeeding is important for the health of young children since it provides not only essential nutrients but also effective protection against various diseases. In the third chapter, I examine the effect of health shocks on the production decisions of agricultural households in Vietnam. I look at whether malaria illnesses experienced by the household have an effect on their agricultural production decisions. While I am not able to entirely overcome issues with endogeneity that are persistent in this literature, results show that profits are negatively associated with the share of household members experiencing malaria. This result is not explained by the decrease in the total number of labor days the household employed. Rather, households appear to change their crop choice to less labor-intensive, less profitable crops in anticipation of these seasonal health shocks.Item Managing Water: Efficiency-Equity Tradeoffs in the Participatory Approach(2010) O'Donnell, Anna; Korzeniewicz, Roberto P; Sociology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation investigates the hypothesis that participation can overcome trade-offs in equity and efficiency. Literature within the field of economics and sociology has argued for tradeoffs in outcomes of allocative efficiency and equity and institutional efficiency and equity, respectively. Community-based participatory institutions are expected to overcome this tension by introducing institutional accountability and local-level decision making, which serve to enhance technical and allocative efficiency while retaining mechanisms for equitable allocation and empowerment. This research draws on fieldwork from a community-managed water supply program in rural Bahia, Brazil to examine whether outcomes of efficiency and equity are mutually compatible. Findings from the field research indicate that explicit and implicit subsidies to the water supply systems led to outcomes of allocative equity in the sites visited, but that these generated tradeoffs with allocative efficiency. Findings from the research also indicated that the community organizations were relatively efficient in their administrative practices, but that this efficiency came at a cost to equality of membership and voice in the community organization. This suggests that participatory water supply programs generate certain and specific costs, although the findings also suggest additional positive externalities associated with participation.Item Information Technology and Rural Market Performance in Central India(2008-04-25) Goyal, Aparajita; Duggan, Mark; Kranton, Rachel; Economics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)How do improvements in information impact market performance? This dissertation examines the effect of an innovative initiative launched by a private company in the central Indian state of Madhya Pradesh. Beginning in October 2000, it set up 1700 internet kiosks and 45 warehouses that provide wholesale price information and an alternative marketing channel to soybean farmers in the state. I develop a theoretical model of this intervention and estimate the impact using a new market-level dataset with spatial geo-coded information. The causal effect is isolated by exploiting the variation in the timing of the introduction of kiosks and warehouses across districts of the state. The estimates suggest an immediate and significant increase in the monthly wholesale market price of soybeans after the introduction of kiosks, lending support to the predictions of the theoretical model. While the presence of warehouses appears to have no effect on price, warehouses are associated with a dramatic reduction in the volume of sales in the traditional markets. Moreover, there is a significant increase in the area under soy cultivation. The estimates are robust to disaggregated measures of treatment and comparisons with alternative crops grown in the same season as soy. The analysis suggests that information can substantially enhance the functioning of rural markets by increasing the competitiveness of buyers.