Contested Certainty and Credibility: The Effect of Personal Stories and Scientific Evidence in User Comments on News Story Evaluation and Relevance

This study examined how user comments influence perceptions of a less-controversial news story. The results of a 2 (argument direction: supporting vs. dissenting comments) × 2 (evidence type: anecdotal vs. scientific evidence referenced in comments) between-subjects factorial design experiment with a no-comments control group ( N = 426) showed that comments have independent effects on the evaluation of medical science news stories on perceived relevance, uncertainty, and risk perception. Also, the types of comments interact with participants’ intellectual humility and subjective numeracy. The findings illustrate that comments may have a deleterious impact on audience perception of journalistic stories and scientific issues.