Online harassment and abusive language continue to be a growing concern on social media platforms. In this study, we explore the power of group dynamics to shape the toxicity of Twitter conversations. First, we examine how the presence of others in a conversation can potentially diffuse Twitter users' responsibility to address a toxic reply. Second, we examine whether the toxicity of the first direct reply to a toxic tweet in conversations establishes group norms for subsequent replies. By doing so, we outline users participating in the conversation before the first toxic reply and the tone of initial responses to a toxic reply as explanatory factors that affect whether others feel uninhibited to post their own abusive or derogatory replies. We test this premise by analyzing a random sample of more than 187K tweets belonging to ~ 9K conversations. This analysis of group dynamics is motivated by a larger body of scholarship on contagion of antisocial behavior and the power of establishing social norms that maintain rather than sanction toxicity. We find evidence that an increased number of users participating in the conversation before receiving a toxic tweet is negatively associated with the number of users who responded to the toxic reply in a non-toxic way. Furthermore, posting a toxic reply immediately after a toxic comment is negatively associated with users posting non-toxic replies and Twitter conversations becoming increasingly toxic. We argue that understanding how social media users respond to uncivil comments or abusive language reveals social norms as powerful social cues that can shape human behavior online.

翻译：在线骚扰和辱骂性语言持续成为社交媒体平台日益严重的问题。本研究探讨群体动态如何塑造Twitter对话中的有害程度。首先，我们考察对话中他人的存在是否可能分散Twitter用户处理有害回复的责任。其次，我们检验对话中首条直接回复的有害程度是否确立了随后回复的群体规范。通过分析，我们将首条有害回复前参与对话的用户数量以及对有害回复的初始反应基调，作为影响他人是否会无拘束地发布自身辱骂性或贬损性回复的解释因子。我们基于约9000次对话中超过18.7万条推文的随机样本进行验证。此群体动态分析的理论动机来自反社会行为传染以及维持而非制裁有害行为的社会规范确立力量的广泛学术研究。结果表明，在收到有害推文前参与对话的用户数量越多，以非有害方式回应有害回复的用户数量反而越少。此外，在有害评论后立即发布有害回复与用户发布非有害回复呈负相关，并与Twitter对话日益恶化相关。我们认为，理解社交媒体用户如何回应不文明评论或辱骂性语言，能够揭示社会规范作为塑造人类在线行为的强大社会线索。