Conflict detection predicts the temporal stability of intuitive and deliberate reasoning

Although the susceptibility to reasoning biases is often assumed to be a stable trait, the temporal stability of people’s performance on popular heuristics-and-biases tasks has been rarely directly tested. The present study addressed this issue and examined a potential determinant for answer change. Participants solved the same set of “bias” tasks twice in two test sessions, two weeks apart. We used the two-response paradigm to test the stability of both initial (intuitive) and final (deliberate) responses. We hypothesized that participants who showed higher conflict detection in their initial intuitive responses at session 1 (as indexed by a relative confidence decrease compared to control problems), would be less stable in their responses between session 1 and 2. Results showed that performance on the reasoning tasks was highly, but not entirely, stable two weeks later. Notably, conflict detection in session 1 was significantly more pronounced in those cases that participants changed their answer between session 1 and 2 than when they did not change their answer between sessions. We discuss practical and theoretical implications.