People Overestimate How Many Social Media Users Post Harmful Content

People can become more cynical about the state of society when they see harmful behavior online. Three nationally representative studies of the American public (N = 1,090) revealed that people consistently and substantially overestimated how many social media users contribute to harmful behavior online. They believed that 43% of all Reddit users have posted severely toxic comments and that 33% of all Facebook users have shared false news online. In reality, platform-level data shows that most of these forms of harmful content are produced by small but highly active groups of users. This misperception was robust to different thresholds of harmful content and operationalizations of harmful content. An experiment revealed that overestimating the proportion of social media users who post harmful content makes people feel more negative emotion, perceive the U.S. to be in greater moral decline, and encourages distorted perceptions of what others desire to see on social media. However, these effects can be mitigated through a targeted intervention that corrects this misperception. Together, our findings highlight a novel perceptual mechanism that may explain why social media use can harm well-being and undermine social cohesion.