The association between personal interest and critical thinking: a comparison between a universal (death penalty) and a local (Strait of Messina Bridge) debate

Introduction: This research examines how different forms of personal interest are associated with critical thinking (CT). While interest is often assumed to enhance engagement and reasoning, its role may depend not only on its intensity but also on its underlying motivational quality. Methods: Two studies investigated the relationship between personal interest and CT. In Study 1, 77 participants completed standardized CT measures and produced open-ended reasoning on two controversial issues: the death penalty (a universal topic) and the Strait of Messina Bridge (a local topic). Participants also rated their personal interest in each issue. In Study 2, 80 participants completed similar CT measures while distinguishing between different types of interest, including epistemic, ego-defensive, and identity-based interest. Results: In Study 1, a nonlinear (inverted U-shaped) relationship emerged for the local topic: both low and high levels of interest were associated with weaker CT performance, suggesting that interest intensity alone does not guarantee critical engagement. No comparable effect was found for the universal topic. Additionally, higher CT scores predicted a greater likelihood of revising one’s stance when exposed to contradictory evidence. Study 2 revealed that epistemic interest, rooted in curiosity, was positively associated with CT, whereas ego-defensive and identity-based interests showed negative associations. Discussion: Overall, these findings indicate that the quality rather than the magnitude of personal interest is more strongly linked to whether it facilitates or impairs reasoning. Interest may enhance CT when driven by epistemic curiosity, but may hinder it when tied to self-protection or identity concerns.