Toward an Understanding of the Psychological Meaning of Physiological Synchrony

Physiological synchrony—mutual changes physiological activity between individuals—has become one of the most frequently studied yet variably-interpreted constructs in psychological science. Decades of research show that physiological synchrony is ubiquitous across relationship and social contexts, but consensus remains elusive about what it means psychologically. We advance an inferential framework for mapping observed synchrony to warranted psychological conclusions by importing classical principles of psychophysiological inference into the interpersonal domain. Building on Cacioppo and Tassinary’s (1990) logic of inference, we treat physiological synchrony as an empirical pattern whose meaning depends on three constraints: specificity (which psychological processes remain plausible given the physiological pattern and plausible alternatives), generality (the contexts, relationships, and timescales over which an interpretation should hold), and sensitivity (detectability of the theoretically relevant dynamics given measurement and modeling choices). We ground these constraints in principles of autonomic organization, emphasizing how physiological ambiguity and modes of control shape what synchrony can and cannot mean, and we use the Biopsychosocial Model of Challenge and Threat as a worked exemplar of how theory-specified multivariate profiles and motivational context strengthen inference. We further argue that model class is an inferential commitment: choices about sampling rate, observation window, preprocessing, and whether coupling is modeled as contemporaneous, lagged, or dynamical determine which forms of coordination are detectable and which interpersonal processes remain viable candidates for interpretation. By integrating contemporary synchrony approaches within this inferential framework, we provide conceptual and methodological guidance for clarifying when physiological synchrony supports strong psychological inference and for specifying the boundary conditions under which those interpretations should generalize.