The study of extremist radicalization typically focuses on how individuals become motivated to carry out violence through the adoption of an ideology. But extremism and ideological formulation are not typically individual ventures, with some rare exceptions. Most forms of extremism— certainly today’s most pressing threats, white nationalism and jihadism—are concerned with group identities (Berger, 2017), with ideologies that develop over generations, with contributions from many different people. Attempts to understand extremist motivated violence outside of these group processes capture only part of the picture.

While the exact boundaries between group and individual motivations can be indistinct, it may be fruitful to approach this problem from a different perspective. Rather than simply asking why individuals radicalize, one avenue for enhanced investigation is to ask: “Why do groups radicalize?” and then ask “Why do people join groups?” Some answers to these questions can be found the context of social identity theory. Specifically, uncertainty identity theory (Hogg, 2004, 2007) offers a promising avenue for exploring why people join extremist groups. Uncertainty identity theory may also provide a window into why some people turn to violence, a question which is related, but not identical, to the question of why they join extremist groups.