Given the centrality of prosociality in everyday social functioning, understanding the factors and mechanisms underlying the origins of prosocial development is of critical importance. This experiment investigated whether experience with reciprocal object exchanges can drive the developmental onset of sharing behavior. Seven-month-old infants took…

This study investigated the development of sharing expectations and sharing behavior in 3 groups of 3-, 4-, and 5-year-old children. We examined (a) whether preschool children expect a person to share more with a friend than with a disliked peer and (b) whether their expectation about others' sharing behavior depends on whether there is a cost or…