Accepted, American Economic Review
Does the consumption of ideologically congruent news on social media exacerbate polarization? I estimate the effects of social media news exposure by conducting a large field experiment randomly offering participants subscriptions to conservative or liberal news outlets on Facebook. I collect data on the causal chain of media effects: subscriptions to outlets, exposure to news on Facebook, visits to online news sites, and sharing of posts, as well as changes in political opinions and attitudes. Four main findings emerge. First, random variation in exposure to news on social media substantially affects the slant of news sites individuals visit. Second, exposure to counter-attitudinal news decreases negative attitudes toward the opposing political party. Third, in contrast to the effect on attitudes, I find no evidence that the political leaning of news outlets affects political opinions. Fourth, Facebook's algorithm is less likely to supply individuals with posts from counter-attitudinal outlets, conditional on individuals subscribing to them. Together, the results suggest that social media algorithms may limit exposure to counter-attitudinal news and thus increase polarization.
Social movements are associated with large societal changes, but evidence on their causal effects is limited. We study the effect of the MeToo movement on a high-stakes decision—reporting a sexual crime to the police. We construct a new dataset of sexual and non-sexual crimes in 30 OECD countries, covering 88 percent of the OECD population. We analyze the effect of the MeToo movement by employing a triple-difference strategy over time, across countries, and between crime types. The movement increased reporting of sexual crimes by 13 percent during its first six months. The effect is persistent and lasts at least 15 months. Because we find a strong effect on reporting before any major changes to laws or policy took place, we attribute the effect to a change in social norms. Using more detailed US data, we show that the movement also increased arrests for sexual crimes in the long run. In contrast to a common criticism of the movement, we do not find evidence for large differences in the effect across racial and socioeconomic groups. Our results suggest that social movements can rapidly change high-stakes personal decisions.