To whom do people reply in comment sections? Effects of attitude (un)congeniality, age, confidence, and knowledge

Phenomena like echo chambers and societal polarization have often been linked to an individual preference for like-minded information (selective exposure). This view has been challenged recently: behavior on comment sections in online forums suggests the opposite dynamic, with users more likely to reply to attitudinally uncongenial content. Three experimental studies (total N = 1524) explore boundary conditions of this uncongeniality bias by measuring participants’ tendency to reply to comments on climate science. Studies 1 (student sample) and 2 (non-student sample) replicate the uncongeniality bias. However, Study 3 (representative for age and gender in Germany) yielded a surprising congeniality bias (a preference for replying to congenial comments) which was driven by participants with higher age. Further results across studies suggest that high confidence increases engagement (general likelihood to reply) but reduces antagonism (likelihood to reply to uncongenial content). Conversely, high knowledge reduces engagement but increases the uncongeniality bias.