ORIGINAL ARTICLE Domains of self-uncertainty and their relationship to group identification Michael A. Hogg* | Namrata Mahajan Department of Psychology, Claremont Graduate University Correspondence Michael A. Hogg, Department of Psychology, Claremont Graduate University, 123 East 8th Street, Claremont, CA 91711. Email: michael.hogg@cgu.edu Abstract Uncertainty-identity theory research shows that self-uncertainty, directly or indirectly manipulated or measured, motivates group identification. Untested is an assumption that it is collective identity-focused uncertainty that most directly motivates identification. Two studies tested this assumption. Study 1 (N 5 140) measured self-uncertainty relating to different aspects of self, with the expectation they would cluster into three distinct domains—individual, relational, collective self-uncertainty. This expectation was supported. Study 2 (N 5 382) manipulated uncertainty (low, high) and domain of self (individual, relational, collective) in a 2 3 3 design and measured identifi- cation. As predicted uncertainty strengthened identification (H1) and this was moderated by domain (H2)—it was only significant on collective self. Implications for self-uncertainty fluidity and uncertainty reduction through group identification are discussed. 1 | INTRODUCTION Social psychologists have long considered uncertainty to play a signifi- cant role in motivating human behavior (e.g., Fromm, 1947), and there are many social psychological analyses of the causes and consequences of various manifestations of uncertainty (e.g., Heine, Proulx, & Vohs, 2006; Kahneman, Slovic, & Tversky, 1982; Kruglanski & Webster, 1996), not least social comparison theory (e.g., Festinger, 1954; Suls & Wheeler, 2000). In recent years, there has also been an emphasis spe- cifically on uncertainty related to or focused on the self (e.g., Arkin, Oleson, & Carroll, 2010; Hogg, 2007; McGregor, Prentice, & Nash, 2009; Van den Bos, 2009). The focus of the present research is on one specific conceptualization of the relationship between self-uncertainty and human behavior—uncertainty-identity theory (Hogg, 2000, 2007, 2012). Uncertainty-identity theory is a motivational account of group identification and group and intergroup phenomena. The key premise is that self-conceptual uncertainty motivates group identification. Uncertainty, particularly uncertainty about oneself or about things that directly matter to or reflect on who we are, can be aversive. People strive to reduce feelings of uncertainty about themselves, their social world and their place within it—they like to know who they are and how to behave, and who others are and how they might behave. Being properly located in this way renders the world and one’s place within it relatively predictable and allows one to plan effective action, avoid harm, know who to trust, and so forth. Group identification is very effective at reducing or protecting against self-related uncertainty. This is because identification is associ- ated with social categorization of self and others—a process that deper- sonalizes behavior and perception of self and other’s to conform to group prototypes that describe and prescribe how people (including oneself) will and ought to behave and interact with one another (Abrams & Hogg, 2010; Turner, Hogg, Oakes, Reicher, & Wetherell, 1987). Social categorization of self and others generates a sense of ingroup identification and belonging, and regulates perception, infer- ence, feelings, behavior, and interaction to conform to prototype-based knowledge one has about one’s own group and relevant outgroups. Furthermore, because group prototypes are shared (“we” agree “we” are like this, “they” are like that) one’s worldview and self-concept are consensually validated. Social categorization makes one’s own and others’ behavior predictable, and allows one to avoid harm, plan action, and know how one should feel and behave. Some types of groups and some features of groups are more effec- tive than others in reducing uncertainty through identification. Highly entitative groups (Campbell, 1958; Hamilton & Sherman, 1996), which are distinctive, homogeneous, and clearly structured, provide common goals and a clearly defined identity and are therefore particularly effec- tive—entitativity moderates the relationship between self-uncertainty *Michael A. Hogg and Namrata Mahajan, Department of Psychology. The studies reported in this article were conducted as part of the second author’s doctoral research at Claremont Graduate University. J Theo Soc Psychol. 2018;1–9. wileyonlinelibrary.com/journal/jts5 V C 2018 Wiley Periodicals, Inc. | 1 Received: 14 October 2017 | Revised: 26 February 2018 | Accepted: 13 March 2018 DOI: 10.1002/jts5.20