Looking Left and Right: Biased Assimilation

We naturally impute credibility—including knowledge and shared interests—to putative experts whose cultural outlooks are congenial to our own. Accordingly, to the extent we defer to credible experts when sorting through competing claims about societal dangers, we are again drawn to beliefs that cohere with our cultural commitments.
The link between perceptions of harm and cultural outlooks, moreover, is unlikely to be severed by disconfirming empirical information. Real-world people tend [not to] update their prior beliefs based on new information, [instead] they tend to evaluate the persuasiveness of new information based on its conformity to their experience. Known as ‘biased assimilation,’ this tendency also has a straightforward cultural explanation: ordinary persons aren’t in a position to identify when new information is credible, and thus a ground for updating their prior beliefs, without recourse to the very same cultural heuristics that have generated their existing beliefs. Biased assimilation is especially strong when the belief under challenge is one that is predominant within a group—such as a cultural one—that is central to a person’s identity. In that situation, acceptance of the new information threatens to drive a wedge between a person and others whose judgment she respects and whose good opinion she values. Accordingly, if the source of the new information is someone perceived to hold cultural commitments opposed to one’s own, the pressure to reject that information is all the more intense. (links/citations in the original 2007 study by Dan M. Kahan: The Cognitively Illiberal State)