It has been demonstrated that stress, experienced outside of a relationship, can spill into a relationship and cross over during interactions from one partner to the other. However, the mechanism of how stress cross over in real-time between partners is still unknown. To overcome this limitation, we invited 189 couples (N = 378 individuals) for two interactions and stressed either the man, the woman, or both partners between the interactions with a standardized stress-induction procedure. Vocally-encoded emotional arousal (i.e., fundamental frequency, indexed as fo) was extracted from both partners in 25,834 talk turns. Dynamical systems modeling revealed four patterns of dynamic influence prior to stress induction, which started to erode after the stress induction. This demonstrates that the initially unstressed mates become stressed during the behavioral exchange and stress crosses over from the unstressed partner to the stressed mates, interfering with their ability to down-regulate stress.
