People nowadays express their opinions in online spaces, using different forms of interactions such as posting, sharing and discussing with one another. These digital traces allow to capture how people dynamically react to the myriad of events occurring in the world. By unfolding the structure of Reddit conversations, we describe how highly engaging events happening in the society affect user interactions and behaviour with respect to unperturbed discussion patterns. Conversations, defined as a post and the comments underneath, are analysed along their temporal and semantic dimensions. We disclose that changes in the pace and language used in conversations exhibit notable similarities across diverse events. Conversations tend to become repetitive with a more limited vocabulary, display different semantic structures and feature heightened emotions. As the event approaches, the shifts occurring in conversations are reflected in the users' dynamics. Users become more active and they exchange information with a growing audience, despite using a less rich vocabulary and repetitive messages. The peers of each user fill up more semantic space, shifting the dialogue and widening the exchange of information. The recurring patterns we discovered are persistent across several contexts, thus represent a fingerprint of human behavior, which could impact the modeling of online social networks interactions.

翻译：如今，人们通过发帖、分享和互相讨论等不同互动形式，在在线空间中表达自己的观点。这些数字痕迹使我们能够捕捉到人们如何动态地应对世界上发生的无数事件。通过解析Reddit对话的结构，我们描述了社会中发生的高参与度事件如何影响用户互动和行为，与未受干扰的讨论模式相比有何不同。对话（定义为帖子及其下的评论）从时间和语义两个维度进行分析。我们揭示出，在不同事件中，对话的节奏和语言变化表现出显著的相似性。对话趋向于重复，词汇更加有限，呈现出不同的语义结构，并带有更强烈的情感。随着事件临近，对话中发生的变化反映在用户的动态中。用户变得更加活跃，与越来越多的受众交换信息，尽管使用的词汇较为贫乏且信息重复。每个用户的同伴占据了更多的语义空间，改变了对话方向并拓宽了信息交换。我们发现的重复模式在多种情境下持续存在，因此代表了人类行为的指纹，可能对在线社交网络互动建模产生影响。