Identity Emergence in the Context of Vaccine Criticism in France

This study investigates the emergence of collective identity among individuals critical of vaccination policies in France during the COVID-19 pandemic. As concerns grew over mandated health measures, a loose collective formed on Twitter to assert autonomy over vaccination decisions. Using analyses of pronoun usage, outgroup labeling, and tweet similarity, we examine how this identity emerged. A turning point occurred following President Macron's announcement of mandatory vaccination for health workers and the health pass, sparking substantial changes in linguistic patterns. We observed a shift from first-person singular (I) to first-person plural (we) pronouns, alongside an increased focus on vaccinated individuals as a central outgroup, in addition to the media and President Macron. This shift in language patterns was further reflected in the behavior of new users. An analysis of incoming users revealed that a core group of frequent posters played a crucial role in fostering cohesion and shaping norms. New users who joined during the week of Macron's announcement and continued posting afterward showed an increased similarity with the language of the core group, contributing to the crystallization of the emerging collective identity. By leveraging large-scale social media data and computational methods, we provide insights into the mechanisms through which resistance movements solidify their identity online in response to policy changes.