Attraction to politically extreme users on social media.

Political segregation is a pressing issue, particularly on social media platforms. Recent research suggests that one driver of segregation is political acrophily-people's preference for others in their political group who have more extreme (rather than more moderate) political views. However, acrophily has been found in lab experiments, where people choose to interact with others based on little information. Furthermore, these studies have not examined whether acrophily is associated with animosity toward one's political out-group. Using a combination of a survey experiment (N = 388) and an analysis of the retweet network on Twitter (3,898,327 unique ties), we find evidence for users' tendency for acrophily in the context of social media. We observe that this tendency is more pronounced among conservatives on Twitter and that acrophily is associated with higher levels of out-group animosity. These findings provide important in- and out-of-the-lab evidence for understanding acrophily on social media.