Why are online political discussions perceived to contain elevated levels of hostility compared to offline discussions? In this manuscript, we leverage cross-national representative surveys and online behavioral experiments to [test] the mismatch hypothesis regarding this hostility gap. The mismatch hypothesis entails that novel features of online communication technology induce biased behavior and perceptions such that ordinary people are, e.g., less able to regulate negative emotions in online contexts. We test several versions of the mismatch hypothesis and find little to no evidence in all cases. Instead, online political hostility is committed by individuals who are predisposed to be hostile in all contexts. The perception that online discussions are more hostile seemingly emerges because other people are more likely to witness the actions of these individuals in the large, public network structure of online platforms compared to more private offline settings.
From https://twitter.com/JonHaidt/status/1166318786959609856: