Motivated numeracy refers to the idea that people with high reasoning capacity will use that capacity selectively to process information in a manner that protects their own valued beliefs. This concept was introduced in a now classic article by Kahan, Peters, Dawson, & Slovic [2017, Behavioral Public Policy 1, 54-86], who used numeracy to index reasoning capacity, and demonstrated that the tendency to engage in ideologically congruent interpretation of facts increased substantially with people's numeracy. Despite the importance of this finding, both from a theoretical and practical point of view, there is yet no consensus in the literature about the factual strength of motivated numeracy. We therefore conducted a large-scale replication of Kahan, Peters, Dawson, and Slovic (2017), using a pre-specified analysis plan with strict evaluation criteria. We did not find good evidence for motivated numeracy; there are distinct patterns in our data at odds with the core predictions of the theory, most notably (i) there is ideologically congruent responding that is not moderated by numeracy, and (ii) when there is moderation, ideologically congruent responding occurs only at the highest levels of numeracy. Our findings suggest that the cumulative evidence for motivated numeracy is weaker than previously thought, and that caution is warranted when this feature of human cognition is leveraged to improve science communication on contested topics such as climate change or immigration.
Keywords: Identity-protective cognition; Motivated numeracy; Motivated reasoning; Replication.
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