Says who? Children consider informants' sources when deciding whom to believe.

To successfully navigate the world, we cannot simply accept everything we hear as true. We must think critically about others' testimony, believing only sources who are well-informed and trustworthy. This ability is especially crucial in early childhood, a time when we both learn the most, and have the least prior knowledge we can fall back upon to verify others' claims. While even young children evaluate testimony by considering whether agents' firsthand experiences license their claims, much of the time, our informants do not possess firsthand knowledge. When agents transmit information learned from others (rather than discovered firsthand), can children also evaluate their testimony's basis? Across 3 experiments ( = 390), we manipulate the number of primary sources originating a claim, and the number of secondary sources repeating it. We find that by age 6, children understand that a claim is only as reliable as its original source, endorsing claims supported by more primary (rather than secondary) sources. While young preschoolers already understand the link between firsthand perceptual access and knowledge, these results suggest that a full understanding of testimony's social basis may be later-developing. (PsycInfo Database Record (c) 2022 APA, all rights reserved).