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Thesis
Peer Reviewed

The Field of Consumption: Statistical Models and Analyses

UC Berkeley Electronic Theses and Dissertations (2016)

This dissertation develops a general quantitative model of field structure for analyzing the field theoretic properties of social phenomena. I use core structural principles found in the dominant variants of field theory (Lewin, Bourdieu, Dimaggio and Powell, Martin, and Fligstein and McAdam) to outline and elaborate a broad class of models consistent with the major assertions of field theory. These models use nonparametric local regressions to estimate field effect over multidimensional social space. By using univariate and multivariate statistics, these models enable determination of the existence or nonexistence of the field, the best description for the axes of the field and the complex patterns of variation in field effects over social space.

In three distinct analyses based on data from the Consumer Expenditure Survey and the Panel Study of Income Dynamics, I demonstrate how the organization of consumption as whole has changed over time and how individuals at different points in social space have been affected. Using a synthetic cohort design, I show how lifecycle consumption is differentiated by age, income, and education, and how these effects interact and moderate each other. Finally, I analyze how households changed their consumption in response the Great Recession. I find that cultural change in consumption preferences are a better explanation for changes in consumption than recession-related economic shocks or drops in consumer confidence.

This dissertation makes two contributions. First, it attempts to further the development of field theory by outlining and demonstrating a quantitative model of field structure. This model offers an improvement over the current state of field modeling in terms of statistical rigor and flexibility. The model I present here enables more detailed and careful analysis of field structure and transformation and is general enough to help adjudicate between competing claims of conflicting field theories. Second, this dissertation highlights the necessity of considering economic and cultural determinants of consumption in conjunction. Consumption patterns are highly contingent on the specific conditions under which individuals make consumption decisions. While income, wealth, and savings are important, age, education, and family size are equally and frequently more important for predicting variations in consumption.

Cover page: The Field of Consumption: Statistical Models and Analyses

Article

Why the Federal Reserve Failed to See the Financial Crisis of 2008: The Role of “Macroeconomics” as a Sense making and Cultural Frame

Working Paper Series (2014)

One of the puzzles about the financial crisis of 2008 is why the regulators were so slow to recognize the impending collapse of the financial system. In this paper, we propose a novel account of what happened. We analyze the meeting transcripts of the Federal Reserve’s main decision-making body, the Federal Open Market Committee (FOMC), to show that they had surprisingly little recognition that a serious economic meltdown was underway even after the collapse of Lehman Brothers on September 15, 2008. This lack of awareness was a function of the inability of the FOMC to connect the unfolding events into a narrative reflecting the links between the housing market, the subprime mortgage market, and the financial instruments being used to package the mortgages into securities. We use the idea of sense-making to explain how this happened. The Federal Reserve’s main analytic framework for making sense of the economy, macroeconomic theory, made it difficult for them to connect the disparate events that comprised the financial crisis into a coherent whole. We use topic modeling to analyze transcripts of FOMC meetings held between 2000 and 2008, demonstrating that the framework provided by macroeconomics dominated FOMC conversations throughout this period. The topic models also suggest that each of the issues involved in the crisis remained a separate discussion and were never connected together. A close reading of the texts supports this argument. We conclude with implications for future such crises and for thinking about sense-making and the role of economics in policymaking more generally.

Cover page: Why the Federal Reserve Failed to See the Financial Crisis of 2008: The Role of “Macroeconomics” as a Sense making and Cultural Frame

Article
Peer Reviewed

Retrotransposons Are the Major Contributors to the Expansion of the Drosophila ananassae Muller F Element.

UC Davis Previously Published Works (2017)

The discordance between genome size and the complexity of eukaryotes can partly be attributed to differences in repeat density. The Muller F element (∼5.2 Mb) is the smallest chromosome in Drosophila melanogaster, but it is substantially larger (>18.7 Mb) in D. ananassae To identify the major contributors to the expansion of the F element and to assess their impact, we improved the genome sequence and annotated the genes in a 1.4-Mb region of the D. ananassae F element, and a 1.7-Mb region from the D element for comparison. We find that transposons (particularly LTR and LINE retrotransposons) are major contributors to this expansion (78.6%), while Wolbachia sequences integrated into the D. ananassae genome are minor contributors (0.02%). Both D. melanogaster and D. ananassae F-element genes exhibit distinct characteristics compared to D-element genes (e.g., larger coding spans, larger introns, more coding exons, and lower codon bias), but these differences are exaggerated in D. ananassae Compared to D. melanogaster, the codon bias observed in D. ananassae F-element genes can primarily be attributed to mutational biases instead of selection. The 5' ends of F-element genes in both species are enriched in dimethylation of lysine 4 on histone 3 (H3K4me2), while the coding spans are enriched in H3K9me2. Despite differences in repeat density and gene characteristics, D. ananassae F-element genes show a similar range of expression levels compared to genes in euchromatic domains. This study improves our understanding of how transposons can affect genome size and how genes can function within highly repetitive domains.

Cover page: Retrotransposons Are the Major Contributors to the Expansion of the <i>Drosophila ananassae</i> Muller F Element.

Article
Peer Reviewed

Drosophila Muller F Elements Maintain a Distinct Set of Genomic Properties Over 40 Million Years of Evolution

UC San Diego Previously Published Works (2015)

The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D. erecta, D. mojavensis, and D. grimshawi F elements and euchromatic domains from the Muller D element. We find that F elements have greater transposon density (25-50%) than euchromatic reference regions (3-11%). Among the F elements, D. grimshawi has the lowest transposon density (particularly DINE-1: 2% vs. 11-27%). F element genes have larger coding spans, more coding exons, larger introns, and lower codon bias. Comparison of the Effective Number of Codons with the Codon Adaptation Index shows that, in contrast to the other species, codon bias in D. grimshawi F element genes can be attributed primarily to selection instead of mutational biases, suggesting that density and types of transposons affect the degree of local heterochromatin formation. F element genes have lower estimated DNA melting temperatures than D element genes, potentially facilitating transcription through heterochromatin. Most F element genes (~90%) have remained on that element, but the F element has smaller syntenic blocks than genome averages (3.4-3.6 vs. 8.4-8.8 genes per block), indicating greater rates of inversion despite lower rates of recombination. Overall, the F element has maintained characteristics that are distinct from other autosomes in the Drosophila lineage, illuminating the constraints imposed by a heterochromatic milieu.

Cover page: Drosophila Muller F Elements Maintain a Distinct Set of Genomic Properties Over 40 Million Years of Evolution