Toward an Understanding of the Psychological Meaning of Physiological Synchrony.

Physiological synchrony-coordinated changes in physiological activity between individuals-is a frequently studied yet variably interpreted phenomenon 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 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. We use established approaches to pattern-based psychophysiological inference, including autonomic modes (i.e., configurations of sympathetic-parasympathetic control) and the biopsychosocial model of challenge and threat, to illustrate how multivariate physiological profiles and theoretically relevant contextual information can constrain psychological interpretation. 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.