Dr. Heather Henderson, Director of the Social Development Laboratory at the University of Miami, explores children’s social development in the context of the networks of relationships and environments they experience. The early origins of social interaction are described in terms of innate preferences and capabilities that quickly become co-ordinated with each other and with social partners. The central role of co-ordinated social interactions in the development of a wide range of skills is discussed. Examples of within-child factors that alter early social interactions are provided as a context for considering the cascading effects of early biases or deficits on the development of later more complex behaviours. The importance of targeting core social abilities through intervention at the level of the individual, relationships, and contexts is discussed.