Integrating multiple time-scales to advance relationship science

It is widely acknowledged that social relationships unfold across multiple time-scales. For example, social interactions that take place over moments, hours, or days also shape relationship change and outcomes over months, years, and even decades. These processes likely unfold in the reverse direction as well: experiences over longer-term timeframes may shape how people interact on a moment-to-moment basis. The increasing availability of intensive longitudinal data and measurement burst designs, as well as creativity in the contexts and modes of data collection--including social media, text messages, and event-contingent sampling--have exploded the possibilities for advancing knowledge on social relationships across multiple time-scales. The aim of this issue is to forward methodological innovations, empirical findings, and future directions in relationship science through the study of social and personal relationships across multiple time-scales.