Does a critic’s expertise matter when people judge a scientific claim?

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Media coverage of scientific disagreements can blur the distinction between experts and non-experts or include dissent from people with vested interests, potentially undermining trust in science and belief in scientific claims. The researchers investigated how a disagreeing source’s expertise and conflicting interests affect trust in scientific experts and belief in their claims, and whether scientific literacy changes these effects.

They conducted three 2 × 2 factorial experiments with a student sample (N = 105), an online sample (N = 110), and a general Australian sample (N = 105). Participants read articles presenting a scientific claim followed by a disagreeing source; the researchers manipulated whether that source had relevant subject-matter expertise and whether they had a vested interest.

In all samples, participants judged the original scientific expert as more trustworthy and the claim as more believable when the disagreeing source lacked relevant expertise than when the source had it. Among students, conflicts of interest also affected belief in scientific claims, but not trust in the scientist, and scientific literacy increased sensitivity to expertise and conflict. The other samples were largely insensitive to vested interests, and scientific literacy had varied effects in those samples.

The researchers concluded that disagreement in news, even from questionable sources, can sway evaluations of scientific claims and scientists. They also highlighted the value of literacy-based interventions in science communication.