Partisan YouTube use and evaluation of knowledge in Korea and the United States: a fresh perspective via the Dunning–Kruger effect.

This study examines how partisan news consumption on YouTube influences individuals' biased evaluations of their own and others' political knowledge, framed through the Dunning–Kruger effect, which describes how people with lower competence tend to overestimate their abilities. Using survey data from South Korea and the United States, the research finds that reliance on attitude-consistent (partisan-congruent) YouTube channels is associated with inflated self-assessments of knowledge, particularly among those with lower actual knowledge. In South Korea, partisan YouTube use also correlates with stronger in-group favoritism and out-group derogation in knowledge evaluations, reflecting collectivistic cultural tendencies, whereas in the United States, these effects are primarily observed in self-evaluations, consistent with individualistic cultural norms. Exposure to counter-attitudinal (attitude-challenging) YouTube content shows weaker and more mixed relationships with knowledge appraisals. The findings suggest that partisan YouTube consumption may contribute to overconfidence and ideological polarization, raising concerns about its impact on democratic discourse.