If You Follow, Will I Tell You? Associations Between Interpersonal Movement Synchrony, Perceived Closeness, and Expressivity

Throughout life, strong social connections foster well-being. Expressing self-relevant information can strengthen these connections. We aim to understand the role of responders’ responsive behavior in promoting speakers’ expressivity and interpersonal closeness by investigating responders’ individual contributions to dyadic movement synchrony. Taking a dyadic perspective, we hypothesized that responders’ motor following (i.e., movement alignment with speakers) is associated with speakers’ perceived closeness and expressivity, and that speakers’ closeness is linked to their own expressivity. We explored interindividual differences with the example of adult age. We analyzed 101 videos of dyadic conversations among unacquainted younger (20–31) and older (69–80) women paired in age-homogeneous or age-heterogeneous dyads. Motor following was assessed via video analyses, expressivity with behavioral coding, and closeness using self-reports. Contrary to our hypotheses, responders’ motor following was not significantly associated with speakers’ perceived closeness or expressivity. However, exploratory analyses considering age as a moderator revealed that among older, but not younger, speakers, responders’ increased motor following was associated with higher perceived closeness. As hypothesized, participants’ higher closeness was linked to their own higher expression of thoughts and feelings. Unexpectedly, participants’ expressivity was linked to their own motor following, suggesting both behaviors reflect conversational engagement. We speculate that older adults may perceive motor following as responsive, possibly indicating age-related differences in social processes.