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

► Network structure effects on emergent spatial patterns of rumor were studied. ► 16-person networks discussed ambiguous situations and individuals selected rumors. ► Homogenous clusters of rumors emerged moderated by network clustering. ► Rumor consensus (pluralities/majorities) increased and rumor beliefs polarized. ► Rumor clustering and consensus amplified rumor polarization (Echo Chamber effect).