Exposure to Opposing Views can Increase Political Polarization: Evidence from a Large-Scale Field Experiment on Social MediaChristopher A. Bail et al. Since published in Proceedings of the National Academy of Sciences, 2018. We surveyed a large sample of Democrats and Republicans who visit Twitter at least three times each week about a range of social policy issues. One week later, we randomly assigned respondents to a treatment condition in which they were offered financial incentives to follow a Twitter bot for one month that exposed them to messages produced by elected officials, organizations, and other opinion leaders with opposing political ideologies. (More at http://www.chrisbail.net/)