Children (3.5-8.5 years; n = 105) heard claims about the occurrence of improbable or impossible events, then were asked whether the events could really happen. Some claims were based on informants' first-hand observations and others were hearsay. A baseline group (n = 56) reported their beliefs about these events without hearing testimony. Neither first-hand claims nor hearsay influenced beliefs about impossible events, which remained low across the age range. Hearsay (but not first-hand claims) did influence beliefs about improbable events. Preschoolers expressed greater belief following hearsay, compared to their beliefs following first-hand claims and compared to the baseline group's beliefs. By contrast, older children expressed less belief following hearsay, compared to their beliefs following first-hand claims and compared to the baseline group's beliefs. [ABSTRACT FROM AUTHOR]