Reasons and the “Motivated Numeracy Effect”

Does the ability to reason well make one less likely to engage in motivated reasoning? Following a paradigm used by Kahan, Peters, Dawson, and Slovic (2013), this study aims to replicate, extend, and explain the surprising finding that those most likely to process politicized data in a biased manner are those who score highest on a measure of numerical proficiency. Although our study found general effects of motivated reasoning, we failed to replicate Kahan et al.’s “motivated numeracy effect”. However, our study did find that, when forced to consider competing statistical interpretations of the data before responding, highly numerate participants were more likely than less numerate ones to choose a correct but belief-contradicting interpretation of data. These results suggest that while numerate participants were biased when generating responses, they were not when evaluating reasons to justify their responses.