The authors discern four trends inimical to fact-based discourse and policymaking: increasing disagreement about facts and the interpretation of them (e.g., “The fact that immigrants are actually less likely to commit crimes than people born in the United States”); the blurring of the line between fact and opinion; the increasing quantity of opinion relative to facts; and declining trust in formerly respected sources of factual information. The volume and velocity of the information flow, combined with the new ability to curate à la carte information menus, erode society’s assumption of a shared set of facts. They also deepen the human proclivity for “confirmation bias” and “motivated reasoning” — people inhabiting information silos, seeking and receiving only congenial facts.
Gerrymandering, “assortative mating” (people from the same socio-cultural backgrounds marrying each other), geographic segregation of the likeminded — all these are both causes and effects of living in echo chambers, which produces polarization. Furthermore, when, on social media and elsewhere, filters and gatekeepers are dispensed with, barriers to entry into public discourse become negligible, so being intemperate or ignorant — or both, in the service of partisanship — are not barriers, and toxic digital subcultures proliferate. Kavanagh and Rich say that not only do new media technologies exacerbate cognitive biases, they promote “the permeation of partisanship throughout the media landscape.” They dryly say, “When the length of news broadcasts increased from two to 24 hours per day, there was not a 12-fold increase in the amount of reported facts.”