What makes us think it through? Experimental evidence for a link between confidence and deliberation

Deliberative, effortful thinking supports better reasoning about science, politics, and everyday problems, but what drives its engagement remains unclear. One possibility is that low confidence acts as a trigger for deliberation. Across four preregistered experiments (N ≈ 1,200), we provide a causal test of this hypothesis. Participants received manipulated feedback about their performance on classic reasoning problems (bat-and-ball or base-rate tasks) presented in standard, single response formats (Studies 1-2) or two-response formats in which participants give both a timed and an untimed response for each problem (Studies 3-4). In the single-response studies, negative feedback reliably reduced confidence and increased response times compared to control and positive feedback. In the two-response studies, negative feedback again reduced confidence and lengthened response times. Critically, it also increased the likelihood of revising initial answers and prolonged second-stage response times—hallmarks of deliberation. Moreover, feedback-affected confidence, measured immediately after initial, timed responses and before deliberation was possible, predicted both revisions and extended second-stage processing. Together, these findings offer robust causal evidence that confidence regulates the deployment of deliberative reasoning and clarify what makes us “think it through”.