Anonymous. (2026). User choice is the larger contributor to ideological exposure filtering on Facebook per Bakshy et al. (2015), though this addresses only the echo-chamber pathway and does not rule out a separate animosity-amplification mechanism that Bakshy did not measure. Isonomia. https://www.isonomia.app/a/9TdpVR16@ed2d1af952e8cf028337ebf6a2569afc02a116568275c44dc36eee8e7870f2fd