Research on personal social networks has focused increasingly on their dynamic nature. Social scientists across subfields have offered theories characterizing how, when, and why personal networks evolve, with applications to a range of populations, social conditions, and life course transitions. A persistent theme in this literature is the tension between stasis and adaptation. That is, personal social networks are characterized by remarkable structural stability and uniformity that belies a high degree of turnover at the level of interactions, individuals, and dyads. This chapter leverages core tenets of complex systems theories to provide insight into this paradox, arguing that personal networks operate in much the same way that complex adaptive systems do. In doing so, six organizing principles of personal network stability and change are offered: 1) Personal social networks serve a critical, unified function; 2) Personal networks adapt to dynamic and uncertain environments; 3) Personal networks are comprised of interconnected subgroups that have distinct, but complimentary functions; 4) Personal networks exhibit a hierarchical structure; 5) The structure of personal networks is relatively stable, while network membership is more dynamic and unpredictable; and 6) The dynamics underlying personal networks are nonlinear. Theoretical and methodological implications are discussed.

In their influential chapter on the boundary specification problem in network analysis, Laumann, Marsden, and Prensky (1989) argued that social network data often do not mirror the true underlying social structures in which individuals are embedded. Rather, the validity of network data hinges on the alignment of network boundaries and the social system or social mechanisms being studied. For this reason, the process of determining which actors and relationships should be included in a network is among the most critical research design issues in social network analysis, requiring a tight alliance of theory and method. Here, we build on Laumann and coauthors’ insights, updating their review with contemporary examples, and extending their ideas to the personal network research design context. We begin by identifying characteristics of personal network research, such as boundary spanning, that introduce unique challenges and opportunities to the boundary definition issue. We then apply concepts from their typology, reviewing common strategies for establishing boundaries through name generators in the context of personal network research designs.