A great deal of what occupies the brain is other people. Humans are social primates, meaning a lot of their brains are concerned with processing social information. It also means people are very affected by relationships – with families, with friends, even with strangers – and by figuring out where they are in any hierarchy. Among social primates, the larger the social group, the larger the cortex – suggesting that processing all that social information takes a lot of brain power. Human brains are specialised for processing social cues – their visual systems, their auditory systems, their emotions are all primed to respond preferentially to other humans. More complex systems allow them to verbalise thoughts and emotions to communicate with others. As humans grow up, just as they learn the links between different bodily feelings and action, they start to learn social conventions. As they become more adept, they make connections between themselves and what they observe in others. This chapter considers the importance of other people in effective learning, with clear implications for the nature and importance of the teacher-student relationship, as well as for the role that peers play in learning.