Date of Award


Degree Type




First Advisor

Park, Ernest

Subject Headings

Polarization (Social sciences), Intergroup relations, Social psychology, Group polarization, Decision making, Small group, Group comparison, Self-categorization


Group polarization occurs when group members have more extreme views after learning others in the group have similar attitudes. This effect has been found in numerous studies (e.g., Stoner, 1969 Mackie, 1986). Several theories, such as self-categorization theory and social comparison theory have been used to explain the phenomenon of group polarization. In the current research, an alternative framework based on optimal distinctiveness theory was proposed as a way to predict group polarization. This theory claims that individuals have two conflicting needs- the need to belong and the need to be distinct. When one of these needs is unmet, people act in specific ways so that the need can be addressed. Because these are conflicting needs, it can be difficult to achieve a balance where both needs are satisfied. There are many different strategies, depending on the context, that people use to establish equilibrium. One goal of the current study is to see if people in groups alter their attitudes as a way to establish optimal distinctiveness. To see if optimal distinctiveness plays a role in group polarization, specific experimental conditions were created where optimal distinctiveness would predict a particular pattern of results that differed from what existing explanations would expect. In moderate group norm condition, optimal distinctiveness and other explanations would predict polarization when needs are unmet. In extreme group norm condition, only optimal distinctiveness would predict less extreme attitudes when the need to be distinct is high. To activate particular needs and explore the role of optimal distinctiveness, a 2 (Group composition: homogeneous vs. heterogeneous) X 2 (Strength of group norm: extreme vs. moderate) mixed experiment was created, with the first factor being between-participants and the second within-participants. Participants read two essays, were given feedback about group norms, and provided their attitudes at multiple points in time. While the primary analyses failed to support for t

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