Friendships constitute important relationships, and often function to reduce stress, but have been under-studied. In mother-child dyads, infants coordinate their stress response with their caregivers without experiencing the stressor themselves. The current study used a modified version of the Trier Social Stress Test to examine whether i) friends are physiologically attuned (i.e., cortisol and progesterone); ii) attunement differs as a function of social acceptance or rejection external to the dyad; and, iii) friends can ‘catch’ a stress response only through non-verbal cues. Friends showed both cortisol and progesterone attunement at the beginning of the study. Friends showed cortisol attunement across time and conditions. Friends’ progesterone levels were significantly, but negatively associated across time and conditions. They did not, however, show a stress contagion as a result of one friend experiencing stress. These findings suggest that cortisol and progesterone play different roles in the attunement of stress and subsequent affiliation.

友谊构成了重要的关系，并经常起到减轻压力的作用，但人们对此并未进行充分的研究。在母二倍体中，婴儿与看护者协调他们的压力反应，而自己却没有遇到压力源。当前的研究使用了Trier社会压力测试的修改版本，以检查i）朋友是否在生理上适应了（即皮质醇和孕酮）；ii）调解因二分体外部的社会接受或拒绝而有所不同；iii）朋友只能通过非语言提示来“捕捉”压力反应。朋友在研究开始时同时显示了皮质醇和孕激素的调节。朋友们在不同的时间和条件下表现出皮质醇的调节。朋友的孕酮水平显着，但在不同的时间和条件下呈负相关。但是，他们没有 由于一位朋友承受压力而表现出压力传染。这些发现表明，皮质醇和孕酮在压力调节和随后的隶属关系中起着不同的作用。