User-generated content online is shaped by many factors, including endogenous
elements such as platform affordances and norms, as well as exogenous elements,
in particular significant events. These impact what users say, how they say it,
and when they say it. In this paper, we focus on quantifying the impact of
violent events on various types of hate speech, from offensive and derogatory
to intimidation and explicit calls for violence. We anchor this study in a
series of attacks involving Arabs and Muslims as perpetrators or victims,
occurring in Western countries, that have been covered extensively by news
media. These attacks have fueled intense policy debates around immigration in
various fora, including online media, which have been marred by racist
prejudice and hateful speech. The focus of our research is to model the effect
of the attacks on the volume and type of hateful speech on two social media
platforms, Twitter and Reddit. Among other findings, we observe that extremist
violence tends to lead to an increase in online hate speech, particularly on
messages directly advocating violence. Our research has implications for the
way in which hate speech online is monitored and suggests ways in which it
could be fought.

本文研究了暴力事件对 Twitter 和 Reddit 等社交媒体平台上恶意言论量和类型的影响，结果表明极端暴力事件会导致在线恶意言论的增加，特别是直接鼓吹暴力的言论。该研究对在线恶意言论的监控具有重要意义，并提出了对抗恶意言论的方式。