Contagion Mechanisms and Emotional Group Polarization Outcomes of Online Toxicity: An Information Ecology Perspective

Drawing on information ecology theory, this study investigates how online toxicity spreads and drives emotional group polarization in Reddit discussions surrounding the Israel–Palestine conflict. Based on a dataset comprising 8,725 posts and 1,628,366 comments, we employ Google’s Perspective API to detect toxic content, BERTopic to extract discussion topics, and a dictionary-based method to measure affective features. The results show that, from the information content perspective, content related to conflict and political topics is more prone to generating toxicity. From the information user perspective, post toxicity reduces the scale of user interaction while simultaneously increasing the level of comment toxicity. Furthermore, the analysis shows that post toxicity provokes comment toxicity by triggering users’ negative or high-arousal emotions, with discrete negative emotions such as anger, sadness, and fear enhancing the positive impact of post toxicity on comment toxicity. From the information environment perspective, the results indicate that post toxicity is not significantly associated with emotional group polarization. Accordingly, post toxicity alone plays a very limited