Social anxiety influences the stress-buffering potential of social presence: Evidence from cardiovascular and affective reactivity under stress

Social presence and social support are fundamental instrumental sources of interpersonal emotional regulation, playing a crucial role in mitigating the impact of stress and negative emotions. This study aims to improve our understanding of the role of relationship type and individual differences in social anxiety in the stress-buffering provided by co-presence of others during stress. A dyadic version of the Trier Social Stress Test (TSST) was employed to experimentally induce stress in a sample of 40 dyads, each comprising a target participant who was paired with a second participant, acting as a supporter. In half of the dyads the target and the supporter were in a romantic relationship (Partner Group), while in the other half they were randomly paired (Stranger Group). Heart rate and psychological stress reactivity were collected during the TSST. Results revealed that participants in the Partner Group exhibited a lower heart rate during the acute stress compared to the participants in the Stranger Group, highlighting that the buffering of the physiological stress activity is stronger within close relationships. Nonetheless, participants in the Partner Group reported more anxiety and stress during the task. Furthermore, social anxiety showed a positive correlation with subjective stress reactivity in the participants in the Partner Group, suggesting that it may hinder the perceived benefit of social support. These findings increase our understanding of stress-buffering mechanisms, emphasizing the interplay between social support, stress reactivity, and interpersonal affective processes, also highlighting the need for additional research characterizing individual differences in social regulation of stress.