Motivated numeracy and enlightened self-government

• Published in: Behavioural Public Policy Vol. 1; no. 1; pp. 54 - 86
• Main Authors: KAHAN, DAN M., PETERS, ELLEN, DAWSON, ERICA CANTRELL, SLOVIC, PAUL
• Format: Journal Article
• Language: English
• Published: Cambridge Cambridge University Press 01.05.2017
• Subjects: Climate change; Cognition & reasoning; Information processing; Politics; Science; United States > US
• ISSN: 2398-063X; 2398-0648
• DOI: 10.1017/bpp.2016.2

Why does public conflict over societal risks persist in the face of compelling and widely accessible scientific evidence? We conducted an experiment to probe two alternative answers: the ‘science comprehension thesis’ (SCT), which identifies defects in the public's knowledge and reasoning capacities as the source of such controversies; and the ‘identity-protective cognition thesis’ (ICT), which treats cultural conflict as disabling the faculties that members of the public use to make sense of decision-relevant science. In our experiment, we presented subjects with a difficult problem that turned on their ability to draw valid causal inferences from empirical data. As expected, subjects highest in numeracy – a measure of the ability and disposition to make use of quantitative information – did substantially better than less numerate ones when the data were presented as results from a study of a new skin rash treatment. Also as expected, subjects’ responses became politically polarized – and even less accurate – when the same data were presented as results from the study of a gun control ban. But contrary to the prediction of SCT, such polarization did not abate among subjects highest in numeracy; instead, it increased . This outcome supported ICT, which predicted that more numerate subjects would use their quantitative-reasoning capacity selectively to conform their interpretation of the data to the result most consistent with their political outlooks. We discuss the theoretical and practical significance of these findings.