Children, while at the same time active and sophisticated explorers, are remarkably sensitive to the fact that other people are rich sources of information about all sorts of topics: social customs, object labels, physical phenomena. They ask questions in order to elicit specific types of information and understand that some people probably have more specified types of knowledge than other people (e.g., doctors are more likely to know about medicine and pilots are more likely to know about airplanes).
But children, in relying on other people for information, are also faced with a serious epistemological challenge: how do they figure out which people and what information to trust? How do they know when knowledge is justified, and whether someone has come about it in a reliable way?