Three essays in applied microeconomics : of norms and networks[Trois essais en microéconomie appliquée : des normes et des réseaux]

This dissertation revolves around two wider topics: social norms and production networks. The first chapter investigates a specific modern-day case study where social norms are leveraged in the fight against online hate speech to shed light on how norms shape political behavior more broadly. Using machine learning techniques, I show that speaking out against hateful views is an effective way of deterring further hate speech. The mechanism that most likely explains this effect is that vociferous contradiction in fact serves as a form of non-monetary punishment that raises the salience of a social norm. The second chapter focuses on the crucial role of image concerns in explaining the effect of social norms on behavior. While there are now plenty of studies showing that image concerns affect people on average, we still know very little about which individuals specifically drive that effect. I introduce a novel laboratory experiment designed to fill this gap. It generates an individual-specific measure of image concern, shows that there is substantial heterogeneity even in a small laboratory sample, and investigates how it correlates with other social preferences. The final chapter of my thesis focuses on production networks and in particular on vertical integration. Vertical integration give rise to anticompetitive behavior or indeed be a motive for it. I discuss one such mechanism, called vertical foreclosure, by which vertically integrating firms disrupt the supply of critical inputs to competitors. I leverage novel production network data to identify mergers and acquisitions between vertically related firms and show taht these mergers affect the supply chains of their rivals, which I interpret as evidence for foreclosure.