Tend-and-befriend toward peers, fight-or-flight toward stressors: A dual response to stress.

As stress levels rise globally, it is critical to understand whether stress promotes or inhibits prosocial behavior. The literature to date provides inconclusive evidence on this question. Here, we investigated whether the effects of stress on prosocial behavior depend on the interaction partner's social role. Specifically, 121 young adults (59 men, 62 women, age range = 18 - 34 years) performed the Trier Social Stress Test for Groups (TSST-G) before dividing resources among themselves and either another participant (i.e., a peer) or a TSST-G jury member (i.e., the stressor). We found that participants behaved less prosocially toward a stress-inducing TSST-G jury member compared to a peer across various behavioral measures (i.e., trust, trustworthiness, sharing, punishment). Overall, our results suggest that individuals adapt their behavior toward others depending on the social role of their interaction partner, behaving more prosocially toward potential allies than toward those who thwart social goals. More broadly, our study highlights the importance of considering situational variables when examining the effect of stress on prosocial behavior.