– Executive Summary –
This thesis investigates the psychological mechanisms underlying ideological extremism in the United States, focusing on how the need for cognitive closure (NFCC) and uncertainty-identity theory (UIT) function as explanatory lenses for the attraction to extremism. In analyzing how individuals navigate uncertainty through rigid ideologies and structured group identities, this work contributes a multidimensional framework to better understand the contemporary landscape of domestic violent extremists.
The starting point of this thesis involves distinguishing between the often-interchanged concepts of extremism, radicalization, and terrorism. Using Clark McCauley and Sophia Moskalenko’s two-pyramids model, this study separates radical opinion from radical action, offering a nuanced categorization system that avoids linear assumptions and acknowledges non-sequential pathways toward political violence.[1] This conceptual distinction is foundational to the argument that ideological extremism can develop and persist independently of violent behavior and that group psychological processes are critical to both.[2] J. M. Berger defines extremism as “the belief that an in-group’s success can never be separated from the need for hostile action against an out-group.”[3]
At the core of this thesis are two psychological constructs: NFCC and UIT. NFCC refers to a motivational desire for solid answers and intolerance for ambiguity. As proposed by Arie Kruglanski, individuals with high NFCC are likely to adopt rigid belief systems, conform to group norms, and defer to authoritarian leadership to satisfy their epistemic needs.[4] In group contexts, these characteristics create a psychological ecosystem marked by group-centrism, in-group favoritism, suppression of dissent, and resistance to ideological diversity—all traits commonly observed in extremist movements.[5]
Complementing NFCC, Michael Hogg’s UIT addresses how individuals experiencing self-conceptual uncertainty seek stability through high-entitativity groups—those perceived as tightly bound, ideologically pure, and hierarchically organized.[6] In such environments, group prototypes and clear social roles help individuals resolve identity ambiguity by defining who they are, how they should act, and who the “other” is.[7] These psychological processes are especially potent under conditions of sociopolitical instability or personal threat, making UIT a powerful tool for explaining the attraction to exclusionary ideologies and group polarization.
Together, NFCC and UIT evaluate the psychological appeal of ideological extremism, particularly the use of moral binaries and ideological narratives that assign blame and offer identity clarity.
[1] Clark McCauley and Sophia Moskalenko, “Understanding Political Radicalization: The Two-Pyramids Model,” American Psychologist 72, no. 3 (2017): 213, https://doi.org/10.1037/amp0000062.
[2] McCauley and Moskalenko, 213.
[3] J. M. Berger, Extremism (Cambridge, MA: MIT Press, 2018), 44.
[4] Arie W. Kruglanski et al., “Groups as Epistemic Providers: Need for Closure and the Unfolding of Group-Centrism,” Psychological Review 113, no. 1 (2006): 89–90, https://doi.org/10.1037/0033-295X.113.1.84.
[5] Kruglanski et al., 87–88.
[6] Michael A. Hogg, “Uncertainty-Identity Theory,” in Handbook of Theories of Social Psychology, ed. Paul A. M. Van Lange, Arie W. Kruglanski, and E. Tory Higgins, vol. 2 (Thousand Oaks, CA: SAGE Publications, 2012), 63.
[7] Hogg, 67.
