Rumor clustering, consensus, and polarization: Dynamic social impact and self-organization of hearsay

The "bottom-up" self-organization of shared sense-making and group decision-making through rumor (unverified information statements in circulation) was investigated in two computer-mediated laboratory experiments on the effects of network clustering (i.e., structural "cliquishness"). Participants in 27 (Study 1) and 33 (Study 2) 16-person laboratory-created networks at three institutions discussed ambiguous situations (e.g., "a professor was found dead") and then chose one of four possible rumors in a judgment task (e.g., "he was killed by an angry student") to explain each situation. Static lattice, "ribbon" (street-like), "family" (connected clusters), random, and dynamic-random configurations were employed. Network clustering led to rumor clustering (emergence of homogenous pockets of rumor choices). There was also evidence for increased consensus, rumor persistence, and belief polarization. Belief polarization was amplified by rumor clustering and consensus. In addition, the extent to which "neighbors" were unified in their disagreement (versus agreement) with the participant tempered confidence increases and strongly affected the selection of rumors that "made the most sense." Results explain rumor persistence and variation, document the role of patterns of connectivity and dynamic social influence processes in unverified collective beliefs, and suggest modification of Dynamic Social Impact Theory to include belief polarization mediated by emergent "echo chambers".