Children as young as 8 years of age can infer that an event did not happen when they fail to retrieve a memory of it but deem the event memorable. However, when children imagine or confabulate an event, they are less likely to monitor expected memorability to determine event occurrence, due to imagination and confabulation increasing the familiarity of the event. Across two experiments involving 8- to 9-year-olds and adults, I investigated whether participants could be trained to attend to the qualities of memory one would expect for enacted events, thus promoting memorability-based inferences to reject the occurrence of familiar but false events. In the present studies, participants enacted, imagined, or confabulated a series of actions differing in expected memorability. Two weeks later, half of the participants received memorability-based training before performing an old/new recognition task in which they were asked to endorse only enacted actions. Imagined and confabulated actions thus constituted highly familiar distracters that were to be rejected. Results indicated that adults, but not children, exhibited increased rejection of high-memorability false events following general training on memorability monitoring (Experiment 1; N = 100). Children's rejection of familiar false events only improved when metacognitive training was provided under conditions that closely mimicked the characteristics of the subsequent retrieval task (Experiment 2; N = 125). Theoretical and practical implications are discussed.