Extremist ideologies are finding new homes in online forums. These serve as both places for true believers, and recruiting-grounds for curious newcomers. To understand how newcomers learn ideology online, we study the Reddit archives of a novel sexist ideology known as the "the Red Pill''. Matching a longstanding hypothesis in the social sciences, our methods resolve the ideology into two components: a "behavioral'' dimension, concerned with correcting behavior towards the self and others, and an "explanatory'' dimension, of unifying explanations for the worldview. We then build a model of how newcomers to the group navigate the underlying conceptual structure. This reveals a large population of "tourists'', who leave quickly, and a smaller group of "residents'' who join the group and remain for orders of magnitude longer. Newcomers are attracted by the behavioral component, in the form of self-help topics such as diet, exercise, and addiction. Explanations, however, keep them there, turning tourists into residents. They have powerful effects: explanation adoption can more than double the duration of median engagement, and can explain the emergence of a long-tail of high-power engagers. The most sticky explanations, that predict the longest engagement, are about status hierarchies.

翻译：极端主义意识形态正在网上论坛中寻找新的家园。 这些意识形态既是真正的信徒的场所,也是好奇的新来者招募的场所。 为了了解新来者如何在网上学习意识形态, 我们研究Reddidi 名为“ 红皮圈” 的新型性别歧视意识形态档案。 匹配社会科学的长期假设, 我们的方法将意识形态分为两个部分: “ 行为” 层面, 关注纠正自我行为和他人行为, 以及“ 解释” 层面, 统一世界观的解释。 然后我们构建一个模式, 说明新来者如何在基本概念结构中穿透。 这揭示了大批“ 游客”, 很快离开的, 以及 人数较少的“ 居民” 群体, 加入该团体并保持数量级的更长。 新人受到行为部分的吸引, 以饮食、 锻炼和成瘾等自助话题的形式。 但是, 解释这些解释, 将游客变成居民。 它们具有强大的效果: 解释收养可以比中位接触时间多一倍, 解释中位参与者最高级的状态。