Abstract
Objective: Dynamic social impact theory (DSIT; Latane, 1996a) suggests that as people influence and are influenced by others in proportion to their strength, immediacy, and number, four group-level phenomena of clustering, correlation, consolidation, and continuing diversity will emerge. The purpose of this article is to apply DSIT and its predecessor, social impact theory (SIT; Latane, 1981), as well as related research on attitude extremity to help elucidate the group processes that led to the January 6, 2021, insurrection of Trump supporters at the U.S. Capitol. Method: We review and critically evaluate the evidence for these theories and then use news reports to discuss ways in which they help explain events before, during, and after the insurrection. We also discuss what the theories would suggest for preventing similar future events. Results: Social influence from a very persuasive and high immediacy communicator along with internet communication among his followers led to clusters of extremifying alternative "truths" that eventually propelled some to act on those beliefs. Conclusions: The ease of online discussion allows group processes to operate at much larger and potentially more dangerous levels than ever before. One hope for moderation may be reducing the importance of the issues involved in people's minds.