This research demonstrates that preschoolers (a) avoid trusting informants with humorous intentions when learning novel information and (b) flexibly consider current intentions rather than initial intentions when determining who to trust. In Study 1 (N=61), 3- and 4-year-olds based their trust on intentions or intentional cues alone, trusting a sincere informant over a joker, even when no prior accuracy or inaccuracy was displayed. In Study 2 (N=32), 3- and 4-year-olds flexibly based their trust on the informants' current intentions or intentional cues rather than their initial ones. Children trusted a sincere informant, who originally joked, over a joker, who was originally sincere. In Study 3 (N=89), 3-, 4-, and 5-year-olds tracked changing intentions, and not just intentional cues, in determining who to trust. Children trusted an informant who joked during training trials but was sincere during test trials over an informant who was ignorant during training trials and was sincere during test trials. However, if the ignorant informant became knowledgeable and the joker continued to joke, the pattern reversed. This is the first study to show that preschoolers consider intentions to joke when learning information. This is also the first study to show that preschoolers do not see trust as stable but rather see it as a function of changing intentions.