Key Insight
Synopsis and slides from Kahan's lecture on motivated numeracy — the finding that higher numeracy increases rather than decreases polarization on culturally contested empirical questions.
Motivated numeracy refers to the finding that numerical reasoning ability — the capacity to understand and correctly interpret quantitative information — does not reduce polarization on culturally contested empirical questions. In fact, the evidence suggests that higher numeracy increases polarization, as numerate individuals deploy their quantitative skills in the service of identity-protective goals.
The key study exposed participants to data that could, depending on how it was summarized, appear to support either the conclusion that a skin cream reduces rashes or the conclusion that it increases rashes. When data was framed neutrally, numerate participants outperformed less numerate ones. When the same data was framed as evidence about gun control effectiveness, the pattern reversed: numerate participants correctly interpreted the data only when the correct interpretation supported their culturally preferred conclusion.
Numeracy improves performance on neutral statistical tasks . On culturally charged tasks, numeracy amplifies identity-protective reasoning — with high-numeracy individuals becoming more polarized than low-numeracy individuals because they are better equipped to construct sophisticated motivated arguments.
The lecture addresses the practical implications. If numeracy does not reliably reduce cultural polarization — and may amplify it — then strategies that focus on improving quantitative literacy as a solution to science communication failures are insufficient. The problem is not cognitive incapacity; it is the deployment of cognitive capacity in the service of identity rather than truth.