Interpersonal Sympathetic Coupling in Emotional Contagion: A Preliminary Study Using Directed Coherence

Interpersonal physiological synchrony is a coded language for emotional and psychological connection, capable of revealing the implicit mechanisms of social interactions. Herein we investigated the interpersonal shared dynamics of the Autonomic Nervous System (ANS) in the context of emotional contagion, focusing on the measurement of interpersonal physiological causal coupling (from now on, IPCC) through Electrodermal Activity (from now on, EDA) analysis. To this end, a novel experimental protocol was designed to induce an emotional connection between dyads of participants by exposing them to emotionally inducing images, alternating phases in which they were alone and together. We estimated IPCC between EDA signals using a measure derived from Granger Causality (GC), given its well-known ability to assess causal coupling between physiological time series. Our results demonstrated how IPCC was lower when individuals were alone compared to when they were together, indicating that social presence enhances physiological coupling. Furthermore, the statistical analysis showed how dyads exhibited a significant increase in coupling during the empathy-inducing activity compared to the resting condition. This suggests that an emotional connection was established between participants. Finally, although interesting trends were observed, no statistically significant preferred direction emerged, suggesting that more analysis is needed to better understand the directional dynamics.