Children often regard adults as infallible sources of knowledge. However, in discussions with their peers children can be freer to question, discuss and explore the world for themselves. Psychologists have often regarded peer interaction as one of the fundamental building blocks of development. This lecture describes research examining how children interact with their peers, and how these interactions are affected by social identities such as gender and ethnicity. It will also consider why children can often learn better through peer interactions than from adult instruction across a range of topics from morality to understanding of science.