In a series of very influential papers, Dan Kahan argues for “the identity protective cognition thesis”: the claim that politically motivated reasoning is a major factor explaining current levels of polarization over matters of fact, especially in the US. An important part of his case consists of experimental data supporting the claim that ideological polarization is more extreme amongst more numerate individuals. In this paper, we take a close look at how precisely this “numeracy effect” is supposed to come about. Working with Kahan’s own notion of motivated reasoning, we reconstruct the mechanism that according to him produces the effect. Surprisingly, it turns out to involve plenty of motivation to reason, but no motivated reasoning. This undermines the support he takes the numeracy effect to provide for the identity protective cognition hypothesis.