Psychologists have emphasized children's acquisition of information through first-hand observation. However, many beliefs are acquired from others' testimony. In two experiments, most 4-year-olds displayed sceptical trust in testimony. Having heard informants' accurate or inaccurate testimony, they anticipated that informants would continue to display such differential accuracy and they trusted the hitherto reliable informant. Yet they ignored the testimony of the reliable informant if it conflicted with what they themselves had seen. By contrast, three-year-olds were less selective in trusting a reliable informant. Thus, young children check testimony against their own experience and increasingly recognise that some informants are more trustworthy than others.