The social curse: Evidence for a moderating effect of shared social identity on contagious stress reactions

Contagious stress describes the transmission of a stress response from a distressed individual (target) to an uninvolved observer. Building on social identity theory, we hypothesize that a shared social identity between the observer and the target as compared to a personal identity increases the likelihood of contagious endocrine and psychological stress responses. Participants underwent the experiment in groups of four or five individuals. After experimentally inducing either a shared social identity or a personal identity, one participant in each group (N_target = 27) was randomly chosen to undergo the Trier Social Stress Test (TSST), while being observed by the rest of the group (N_observer = 89). Salivary cortisol and psychological stress responses were assessed repeatedly during the experiment. As predicted, the likelihood of cortisol stress reactions was significantly higher in the social identity condition (25 %) as compared to the personal identity condition (7 %). No effect of our manipulation on psychological stress responses was found. We also tested whether observers' trait empathy moderates contagious stress and found no support for this moderation.