Chapter 3. Representing Trends and Moment-to-Moment Variability in Dyadic and Family Processes Using State-Space Modeling Techniques

State–space modeling techniques provide a convenient modeling platform for representing systematic trends as well as patterns of intraindividual variability around these trends. Their flexibility in accommodating multivariate processes renders them particularly suited to studying dyadic and family processes that show complex ebbs and flows over time. Using dyadic data collected during the Face-to-Face/Still-Face (FFSF) procedure, examples are provided to explicate the use of state–space models to capture two kinds of changes: systematic trends that are relatively smooth and slow-varying, and transient patterns of intraindividual variability that are manifested on a moment-to-moment basis. Consider the various forms of change processes that may be encountered in the studies of dyadic and family processes. In some cases, researchers may wish to focus on extracting systematic trends that are “smooth,” or unfold in structured ways. Such processes are referred to as intraindividual trends in the present chapter and examples may include a child who becomes more distressed as his/her attempts at getting a parent to comply with a request are repeatedly