The chapter addresses mechanisms and processes underlying the life span ontogeny of social motivation. Six propositions on the life span development of personal relationships are presented. From birth to death individuals are active agents, who coregulate the structure, function, and quality of their social worlds in accordance with their age-specific needs and resources. An individual's developmental resources determine the lifelong salience and outcomes of two kinds of basic goal commitments, a striving for social agency and a striving for belongingness in one's social world. The interplay and dynamic between these two sets of goals determines an individual's interpersonal functioning and competence. A goal-resource-congruence model of social self-regulation suggests that individuals may benefit from matching their social strivings to their resources and potentials.

Why do individuals seek to maintain personal relationships over time? Few issues appear as self-evident and yet at the same time inexplicable. At birth everyone has a mother and a father. Most people have siblings, uncles and aunts, cousins, nephews and nieces. Very rarely do people grow up without an intimate partner, a close friend, or acquaintances. It seems impossible to imagine a well-functioning society without the networks of strong and weak ties that transmit social information, sanction desirable or undesirable behaviors, and provide a social backup in times of misery (Fiske, 1992; Granovetter, 1973; Parsons, 1961; Wiese, 1955). An individual's personal network of relationships constitutes a complex structure and is as much an outcome as it is a determinant of behavioral development.

This chapter introduces a life-span perspective on personal relationships by emphasizing how the structure, processes, and outcomes of relationships are interwoven with human development. The social arena serves as a metaphor for changes and continuities individuals experience in their social partners, activities, and goals over the life span. We consider mutual influences between individual development and relationship partners, including 1) individual changes, 2) the development of relationships themselves, and 3) the context of the larger social network. A life-span understanding of personal relationships considers the structure of relationships (e.g., the types of social partners individuals of different ages interact with), the processes underlying personal relationships (e.g., personality, motivation for social contact, cognition), and the outcomes or precursors of relationship change across the life span.

We, the editors of this book, are parents of young children. As a result, when the weather allows it, we spend considerable time at our local parks and frequently have the opportunity to observe a microcosm of life-span relationships. People of all ages engage in activities, from sitting under a tree watching the clouds, to playing softball in mixed groups of adults and children. Our little ones vie for attention among the other children who run around the slide or swings. Older children throw balls or participate in organized activities. A group of teenagers sit apart and listen to music on a portable compact disc player. Multiple generations come together for a family picnic. Young couples hold hands as they stroll.