We show that isolated capital cities are robustly associated with greater levels of corruption across US states, in line with the view that this isolation reduces accountability. We then provide direct evidence that the spatial distribution of population relative to the capital affects different accountability mechanisms: newspapers cover state politics more when readers are closer to the capital, voters who live far from the capital are less knowledgeable and interested in state politics, and they turn out less in state elections. We also find that isolated capitals are associated with more money in state-level campaigns, and worse public good provision.

We examine how social interactions and friendships shape students' political opinions in a natural experiment at Sciences Po, a leading French university specializing in social and political sciences. The quasi-random assignment of students into short-term integration groups before their academic curriculum reduces political opinion gaps and fosters friendship formation. Using same-group membership as an instrumental variable for friendship, we find that friendship reduces opinion differences by 40% of a standard deviation in the opinion gap. Our evidence supports a homophily-enforced mechanism: friendships form among initially politically similar students, leading them to join political associations together, reinforcing their similarity. However, friendship does not significantly influence politically dissimilar pairs. Instead, it reduces opinion divergence without enforcing ideological convergence.

We conducted online field experiments in large real-world social networks in order to decompose prosocial giving into three components: (1) baseline altruism toward randomly selected strangers, (2) directed altruism that favors friends over random strangers, and (3) giving motivated by the prospect of future interaction. Directed altruism increases giving to friends by 52% relative to random strangers, whereas future interaction effects increase giving by an additional 24% when giving is socially efficient. This finding suggests that future interaction affects giving through a repeated game mechanism where agents can be rewarded for granting efficiency-enhancing favors. We also find that subjects with higher baseline altruism have friends with higher baseline altruism.

We study the stock market performance of firms with Jewish board members during the “Dreyfus Affair” in 19th century France. In a context of widespread latent antisemitism, initial accusations made against the Jewish officer Alfred Dreyfus led to short-lived abnormal negative returns for Jewish-connected firms. However, investors betting on these firms earned higher returns during the period corresponding to Dreyfus' rehabilitation, starting with the publication of the famous op-ed J'Accuse! in 1898. Our conceptual framework illustrates how diminishing antisemitic biases among investors might plausibly explain these effects. Our paper provides novel insights on how antisemitism can increase and decrease over short periods of time at the highest socio-economic levels in response to certain events, which in turn can affect firm value in financial markets.