Relationships are pervasive in human life, both personal and professional, and they are formed, maintained, and strengthened or weakened through human interactions. However, human interactions can be complex and multi-scale, meaning they occur at different time scales (e.g., seconds to lifetimes), across multiple modalities (e.g., movements and speech), and at different levels of organization (e.g., genetic, neural, behavioral; Abney et al. 2014; Dumas et al. 2014). Effective interactions with others seem to be facilitated in contexts such as conversations, teamwork, romantic partnerships, and psychotherapy by the degree to which we engage in multi-modal coordination with others (Dale et al. 2013; Gorman et al. 2016; Imel et al. 2014; Louwerse et al. 2012; Timmons et al. 2015).