Social relations across the life span: in search of unified models.

The authors in this collection have addressed topics of great relevance to the study of social relations across the life span, including the application of family systems models, the development of friendship relations, and the consequences of sibling conflict. Issues considered in this discussion are 1) the value of conceptualizing social development as a life-long process, 2) theoretical and methodological implications of a life course perspective on social relations, and 3) how the collaborative efforts represented in these articles contribute to achieving unified models of life span social development. The collaborators are lauded for their progress toward formulating valid and useful models of family and friendship relations across the life span. The social convoy model is suggested as a broader framework for organizing life span developmental research on diverse relationships.