Individuals often honor sunk costs by increasing their commitment to failing courses of action. Since this escalation of commitment is fueled by self-justification processes, a widely offered prescription for preventing escalation is to have separate individuals make the initial and subsequent resource allocation decisions. In contrast to this proposed remedy, four experiments explored whether a psychological connection between two decision-makers leads the second decision-maker to invest further in the failing program orchestrated by the initial decision-maker. Across three different contexts (financial investments, personnel decisions, and auctions), we found that multiple forms of psychological connectedness (perspective-taking, shared attributes, and interdependent mindsets) led decision-makers to vicariously justify others’ initial decisions and escalate their own commitment to these decisions – even in the face of direct financial costs to themselves, and even among economics students trained in the irrationality of honoring sunk costs. The ability of subtle psychological connections to undermine the conventional prescription for de-escalation has important implications for organizations, public policy, and theories of escalation.