‘Questioning’ the Truth Effect: Processing information in interrogative form reduces (but does not cancel) repetition-induced truth

People attribute higher truth to information they have previously been exposed to. This “truth effect” is resistant to many interventions aimed to reduce it. In three preregistered experiments, we explored whether processing largely unknown information in the form of questions could counteract repetition-induced truth. In Experiment 1 (N = 100), participants judged the truth of repeated and unrepeated sentences. Half of the participants processed sentences in declarative form and the other half processed them in interrogative form during exposure and judgment. A significant interaction between sentence repetition and sentence form emerged, with a significant truth effect in the declarative condition but not in the interrogative. Experiment 2 (N = 325) introduced an additional interrogative condition presenting sentences as questions only during the exposure phase. Compared with the declarative condition, the truth effect was greatly reduced, but still significant, in both interrogative conditions. Experiment 3 (N = 235) employed a within-participant design to manipulate both repetition and sentence form. We confirmed that the truth effect was substantially reduced for interrogative sentences. Additionally, repetition had a smaller effect on certainty about truth judgments for interrogative compared with declarative sentences. We discuss how these findings inform theoretical accounts of the truth effect and their implications for debiasing strategies.