“Self-Fulfilling Misperceptions of Public Polarization”

Mass media convey deep divisions among citizens despite scant evidence for such ideological polarization. Do ordinary citizens perceive themselves to be more extreme and divided than they actually are? If so, what are the ramifications of such misperception? A representative sample from California provides evidence that voters from both sides of the state’s political divide perceive both their liberal and conservative peers’ positions as more extreme than they actually are, implying inaccurate beliefs about polarization. A second study again demonstrates this finding with an online sample and presents evidence that misperception of mass-level extremity can affect individuals’ own policy opinions. Experimental participants randomly assigned to learn the actual average policy-related predispositions of liberal and conservative Americans later report opinions that are 8-13% more moderate, on average. Thus, citizens appear to consider peers’ positions within public debate when forming their own opinions and adopt slightly more extreme positions as a consequence.

“The Parties in Our Heads: Misperceptions About Party Composition and Their Consequences” (co-authored with Gaurav Sood)

We document a consequential and heretofore unnoted perceptual phenomenon in American politics and public opinion: people considerably overestimate the share of party-stereotypical groups in the mass-level parties. For instance, people think that 32% of Democratic sup- porters are LGBT (6% in reality) and 38% of Republican supporters earn over $250,000 per year (2%). We demonstrate that these perceptions are genuine and party-specific, not artifacts of expressive responding, innumeracy, or ignorance of base rates. These misperceptions are relatively universal across partisanship and positively associated with political interest. With experimental and observational evidence, we document consequences of this perceptual bias: misperceptions are associated with partisan affect and attitudinal polarization, and when provided information about the actual share of various party-stereotypical groups in the out-party, partisans see supporters of the out-party as less extreme and feel less socially distant from them. Thus, people’s skewed mental images of the parties appear to fuel intense partisanship.

“Irresponsible Partisanship and Democratic Accountability: How Citizens Understand Party Conflict”

American citizens resent contemporary party conflict largely for its “process consequences.” These include incivility, gridlock, and government dysfunction. This is puzzling because political science generally concludes that such “irresponsible partisanship” is strategic. That is, Democratic and Republican politicians manipulate and intensify conflict as an electoral and messaging strategy. I evaluate potential resolutions for this puzzle, namely that citizens perceive party conflict as affectively-driven rather than strategic—and, importantly, that their tendency to see their own party as motivated by in-group love and the out-party by out- group hate impedes their ability to hold elites accountable for its process consequences. With data from the 2015 IGS-California Poll, I find citizens see both parties as significantly more motivated by strategy than emotion, especially when conflict is presented in less abstract, more policy-related terms. However, I also show that citizens generally oppose or lack strong attitudes toward reforms that could potentially curb process consequences. This suggests that blindness to institutional externalities, rather than to elite strategy, sustains irresponsible partisanship.

Short Bowel Syndrome (SBS) is a condition that occurs due to an insufficient amount of small intestine needed for nutrient absorption and water regulation of the body. A compression spring device is being developed in order to provide a mechanical stimulus to the tissue, as this type of force has been shown to promote lengthening of the tissue. The research completed in this thesis investigated the mechanical characteristics of the spring device and attempted to relate it to the functionality in rat and porcine intestinal tissue.

Results from the evaluation of the springs show that Poly(å-caprolactone), or PCL, is a sufficient polymer to use for creating a biodegradable device as the spring dimensions can be adjusted through variations in the diameter, thickness, and band size in order to provide an adequate spring constant for multiple animal types. Design of the springs, however, need to take into account the size of the gelatin capsule used, the amount of plastic deformation and creep behavior of the spring under compression for an extended time period, and the variation in the mechanical properties of the animal soft tissue that requires lengthening.

Integration of the spring in-continuity requires a feature that will provide a mechanical resistance to force that is greater than the force of the spring in the compressed state. The spring still requires further development and any design should also take into account the possibility of intestinal perforations or obstructions. The polymer spring device provides a good means towards developing a treatment option for SBS, and other potential soft tissue lengthening needs of the body.

An enduring mystery since Apollo is that, in spite of the Moon's lack of a global magnetic field, the surface is nevertheless dotted with regional magnetic fields strong enough to be detected from orbit. Did the Moon once have an intrinsic global field that magnetized parts of the crust but has since decayed away? This is a question of fundamental importance to understanding the formation and evolution of solid planetary bodies, and yet it remains unanswered due in part to limitations in our knowledge of these crustal magnetic anomalies. Adding to the puzzle, many of these magnetic anomalies are accompanied by enigmatic optical features, known as swirls, which may hold the key to understanding "space weathering"—a process by which airless bodies change color over time due to exposure to solar wind and micrometeoroids. Here we show both that swirl morphology provides information about the structure of the underlying magnetic sources, and that the color of the lunar surface varies systematically with latitude in a way that allows us to distinguish between the effects of solar wind ion and micrometeoroid bombardment, addressing a decades-old problem in remote sensing, and aiding in the interpretation of the spectra of airless bodies throughout the solar system.

The remarkable diversity of the outer solar system's satellites provides important clues about the formation and evolution of the solar system. Many of the satellites have surprisingly young surfaces, owing in some cases to on-going geologic activity. Moreover, the existence of subsurface oceans within some of the satellites raises the intriguing possibility of extant habitable environments in the outer solar system. Determining the properties of their ice shells and the structures of their deep interiors places fundamental constraints on how the icy satellites formed and evolved, and on what governs their behavior today. Using gravity and topography data from Cassini, we develop analytical models showing that Titan's ice shell may be very rigid and therefore unlikely to be geologically active. In contrast, we also model the internal structure of the tiny, but highly geologically active moon Enceladus, and find that a subsurface liquid ocean is likely.