Terrorism, radicalization and de-radicalization

• A model of radicalization and de-radicalization is presented.
• We specify the main characteristics of radical groups.
• We outline the micro, meso and macro factors in radicalization.
• Group membership and intergroup relations play crucial roles in radicalization.

In this article, we review the literature and present a model of radicalization and de-radicalization. In this model, we distinguish three phases in radicalization: (1) a sensitivity phase, (2) a group membership phase and (3) an action phase. We describe the micro-level, meso-level and macro-level factors that influence the radicalization process in these three phases. However, not all people become increasingly radical — they may also de-radicalize. We specify the micro-level, meso-level and macro-level factors in de-radicalization. We highlight the importance of the role of group membership and intergroup relations in the radicalization process.