The present study investigated how knowledge-gaps, measured by feeling-of-knowing, and individual differences in epistemic curiosity contribute to the arousal of state curiosity and exploratory behaviour for 265 (210 women, 55 men) university students. Participants read 12 general knowledge questions, reported the answer was either known (“I Know”), on the tip-of-the-tongue (“TOT”), or unknown (“Don't Know”), and indicated how curious they were to see each answer, after which they could view any answers they wanted. Participants also responded to the Epistemic Curiosity (...) (EC) and Curiosity as a Feeling-of-Deprivation (CFD) scales. “TOT” was associated with the smallest knowledge-gap, most curiosity and exploration, and feelings of uncertainty and tension as measured by the CFD scale. “Don't Know” corresponded with the largest knowledge-gap, less curiosity and exploration, and positive feelings of interest as measured by the EC scale. “I Know” states, which reflected the absence of a knowledge-gap, involved the least curiosity and exploration. (shrink)