Working Papers

This paper examines how new identity markers emerge, spread, and define enduring social boundaries. I study Reformation Germany (1480–1806) using 4.9 million baptismal names from 2,210 towns to trace how families expressed religious affiliation through naming choices. Naming remained nearly identical across Catholics and Protestants for decades after 1517 but diverged sharply from 1580 onward, stabilizing by 1618. Church enforcement strengthened local identities, while social learning and conformity spread them across space. Using a staggered difference-in-differences design around Jesuit and Protestant college foundings—complemented by counterfactual placements and visitation records—I show a strong link between institutional presence and local alignment. Applying a DeGroot model of learning with spatial-lag specifications, I show that towns updated their naming toward locally shared beliefs and prevailing norms, producing lasting cultural and economic divides.

The spread of propaganda and misinformation from autocratic regimes is a growing concern in democracies. We study the European Union’s ban on Russian state-backed news outlets after the 2022 invasion of Ukraine, analyzing 677,780 tweets from 146,633 users with a difference-in-differences design in a daily panel. The ban reduced pro-Russian tweets by 10.9% per active user day, with strongest effects among users directly connected to the banned outlets. We find no evidence of substitution to secondary suppliers. Evidence on mechanisms indicates that the ban curtailed pro-Russian content by removing key agenda-setters. Finally, we examine the costs of censorship in a democratic context: A pre-registered experiment finds reduced satisfaction with free speech, particularly among political centrists.

Political polarization is a growing concern in many countries. Are mass protests merely a sign of increasing cleavages, or do they polarize societies? In this paper, we estimate the impact of Nazi marches in 1932 Hamburg, using granular data from 622 voting precincts during 6 elections. We show propaganda can convince – but it does so the most in areas with high initial support. Importantly, marches can also backfire, repelling voters. Thus, political campaigning leads to polarization. These effects diffused through social networks, measured as contagion patterns across neighborhoods from the 1918 Spanish flu outbreak. The electoral effects of social spillovers are of similar importance as direct exposure, and grow over time.