Social relationships are central to human life, but how do they shape the ways the mind and body respond to threat, safety, and distress? In this talk, I examine this question through a research program focused on the regulatory functions of social connection. I first ask why social disconnection is so distressing, and what that can reveal about the role of social connection in human survival. I then explore how close others reduce distress, considering the possibility that loved ones may do more than provide comfort—they may fundamentally alter how threat is processed. Finally, I examine whether caregiving and prosocial behavior represent another important pathway through which social relationships regulate threat responses and influence well-being. Together, this work highlights a central idea: social relationships are not simply part of the backdrop of human life, but they fundamentally shape how our minds and bodies interpret and respond to reality.