Physical Proximity With Social Support Regulates Vigilance to Threat: Evidence From Startle Reactivity During Emotional Stress Induction

Access to social support during emotional stress is one of the most important factors for the successful regulation of stress-induced psychophysiological activation, and is predictive of improved health and well-being. In this research we wanted to deepen our understanding of this buffering effect, focusing on the modulation of the startle reflex during a standardized stress induction as a function of the proximity with social resources as well as the relationship type with them. Seventy participants were exposed to the Trier Social Stress Test (TSST) in one of three possible conditions: Alone, Together with their romantic partner, or Together with a stranger. Startle reactivity to a series of acoustic probes presented during the task was measured along with self-reported levels of anxiety. Results indicate that, independently of the social manipulation, stress induction is associated with a strong inhibition of the startle reflex. Furthermore, we found that access to social resources buffers this startle inhibition, showing that being together with others when facing a stressor regulates threat vigilance. We interpret these findings through the lens of the Social Baseline Theory, suggesting that startle dynamically tracks the load sharing process by which proximity with social resources optimizes the physiological as well as cognitive regulation of behavior in a threatening environment.