Testing Public (Un)Certainty of Science

This exploratory study examines whether readers’assessments of the certainty of scientific findings depend on characteristics of news stories. An experimental design tested whether adding controversy and/or context to a news story about global warming influenced readers’ perceptions of its certainty. Respondents (N = 209) were randomly assigned to read one treatment and answer a questionnaire. Overall, there was a significant difference in readers’assessment of the certainty of global warming across treatments (F = 12.59, p = .00). The context treatment produced the highest level of certainty about global warming and differed significantly from the control treatment (with neither context nor controversy) and from the controversy treatment. Control and controversy treatments resulted in the lowest levels of certainty. There was an interaction effect between treatment and environmental ideology upon certainty (F = 1.64, p = .03) and a correlation between environmental ideology and prior certainty about global warming (r = .35, p = .01), suggesting that those with proenvironmental ideology were less swayed by the treatments.