Credibility Staining and the Boundaries of Expertise: The Reputational Cost of Commenting on Polarized Topics

This study introduces the concept of credibility staining, the reputational harm experts may experience when their commentary on polarizing issues undermines perceptions of their trustworthiness and expertise, even within their own domain. Such risks are increasingly relevant in today’s digital media environment, where experts often offer opinions on contentious topics outside their area of expertise. We tested this phenomenon using a 2x2 factorial experiment in which participants viewed a fictitious marine biologist’s tweets on both a domain-relevant issue (fishing zone expansion) and a domain-irrelevant, polarized issue (gun control). When the expert’s stance on gun control conflicted with participants’ beliefs, perceived credibility declined – even in their area of specialization. These effects were strongest among highly partisan individuals. The findings highlight how ideological alignment shapes credibility judgements and underscore the reputational risks of epistemic trespassing in digital discourse. We discuss implications for science communication and public trust in expertise.