Face masks are one of the cheapest and most effective non-pharmaceutical interventions available against airborne diseases such as COVID-19. Unfortunately, they have been met with resistance by a substantial fraction of the populace, especially in the U.S. In this study, we uncover the latent moral values that underpin the response to the mask mandate, and paint them against the country's political backdrop. We monitor the discussion about masks on Twitter, which involves almost 600K users in a time span of 7 months. By using a combination of graph mining, natural language processing, topic modelling, content analysis, and time series analysis, we characterize the responses to the mask mandate of both those in favor and against them. We base our analysis on the theoretical frameworks of Moral Foundation Theory and Hofstede's cultural dimensions. Our results show that, while the anti-mask stance is associated with a conservative political leaning, the moral values expressed by its adherents diverge from the ones typically used by conservatives. In particular, the expected emphasis on the values of authority and purity is accompanied by an atypical dearth of in-group loyalty. We find that after the mandate, both pro- and anti-mask sides decrease their emphasis on care about others, and increase their attention on authority and fairness, further politicizing the issue. In addition, the mask mandate reverses the expression of Individualism-Collectivism between the two sides, with an increase of individualism in the anti-mask narrative, and a decrease in the pro-mask one. We argue that monitoring the dynamics of moral positioning is crucial for designing effective public health campaigns that are sensitive to the underlying values of the target audience.

翻译：口罩是对抗COVID-19等空气传播疾病最廉价且最有效的非药物干预措施之一。然而，这一措施在美国等地区遭遇了相当比例民众的抵制。本研究揭示了支撑民众对口罩强制令反应的潜在道德价值观，并将其置于美国的政治背景中进行分析。我们追踪了Twitter上关于口罩的讨论，涉及近60万用户在7个月时间跨度内的数据。通过结合图挖掘、自然语言处理、主题建模、内容分析和时间序列分析等方法，我们刻画了支持与反对口罩强制令双方的回应特征。我们的分析基于道德基础理论和霍夫斯泰德文化维度理论框架。研究结果表明：虽然反口罩立场与保守派政治倾向相关，但反口罩者所表达的道德价值观与保守派通常使用的价值观存在差异。具体而言，对权威和纯洁价值观的预期强调伴随了罕见的群体内部忠诚缺失。我们发现，在强制令实施后，支持与反对双方都减少了对"关怀他人"的重视，转而增加对"权威"和"公平"的关注，使得该议题进一步政治化。此外，口罩强制令逆转了个体主义-集体主义在两方之间的表达：反口罩叙事中的个体主义增强，而支持口罩叙事中的个体主义减弱。我们认为，监测道德定位的动态变化对于设计能敏感回应目标受众潜在价值观的有效公共卫生宣传活动至关重要。