Previous research reports a negative association between individuals’ tendency to endorse right- versus left-wing socio-cultural views and performance in cognitive tasks. We hypothesized that this association results to some extent from explicit epistemic preferences and low motivation to perform well in such tasks, rather than resulting from low ability only. In two studies we found support for this hypothesis. In Study 1, we show that part of the association of right-wing authoritarianism (RWA) with performance in the cognitive reflection task (CRT) could be explained by the motivational construct of need for cognition. In Study 2, we experimentally manipulated the motivation of participants by providing (vs. not providing) monetary incentives in the CRT and documented an improvement in the performance of participants high in RWA but not of participants low in RWA. The crucial role of ideology-based motivational differences in the context of cognitive performance is discussed.