Synthesizing Research on Radicalization: Insights from a Text-Mining Systematic Review

The study of radicalization encompasses a broad spectrum of perspectives, with scholars and experts from diverse disciplines – ranging from psychology, sociology, political science, criminology, to economics – contributing to its multifaceted comprehension. Despite this substantial body of empirical research, the knowledge is fragmented across disciplines, emphasizing the need for integration to establish a cohesive framework. As laying the groundwork for a unified framework begins with identifying relevant phenomena, this systematic review analyzed 4019 research articles using text mining to detect phenomena associated with radicalization. Author keywords and abstracts were analyzed by examining term frequency as an indicator of relevance and term co-occurrence as an indicator of association. The results reflect themes commonly featured in theory, such as ideology, identity, and social networks, but also identified themes not well-developed in theory. Macro-level phenomena, including the role of the state, economy, elections, policy, and regional factors, as well as micro- and meso-level phenomena like the internet, social media, adolescence, personality, language, education, and mental health, are not sufficiently embedded in theory. The findings further provide the first empirical evidence confirming the fragmentation of research on radicalization. This review represents a crucial step toward synthesizing existing knowledge and advancing a unified understanding of radicalization.