Mario D. Molina

Ph.D. Candidate


I am a Ph.D. candidate in the Department of Sociology with a minor in Statistics. I study social dynamics of differentiation and integration in groups using different statistical and computational tools, including online experiments, panel data, machine learning, and natural language processing. My research centers on reward systems, social norms, and cultural integration, with an emphasis on the individual mechanisms that contribute to the existence of complex social structures.


Economic Sociology, Social Networks, Social Stratification, and Computational Social Science.

Committee members:

Michael Macy (co-chair), Victor Nee (co-chair), Filiz Garip, and Martin Wells (Statistics).


Social structure, group dynamics, and their influence on individual behavior.

My dissertation broadly explores the effects of social structure and group dynamics on individual beliefs and behaviors. The first chapter studies status hierarchies and their effect on individual effort in a large online community. Specifically, I collect publicly available data from StackOverflow to test the hypothesis that individuals who gain access to higher levels of reputation free-ride from their social status and rest on their laurels by decreasing their individual effort. The second chapter focuses on opportunity structures and perceptions of inequality. Using a novel experiment based on a card game in which the distribution of opportunity matters for the distribution of outcomes, I study whether perceptions of inequality change as opportunities are manipulated to favor either winners or losers. A third chapter examines whether social norms of cooperation, learned in one’s community, spillover into cooperation with complete strangers. I use unique data from key economic actors in the Chinese economy and test whether business norms of cooperation, prevalent in their own community, increase the probability of cooperation with strangers, as measured by a one-shot Prisoner’s Dilemma played against unknown others.