As with standard models of rationality, theorists generally treat prospect theory's demonstration of risk aversion in gains but risk tolerance in losses as domain-general. Yet evolutionary psychology suggests that natural selection has designed a domain specific cognitive architecture—with systems specialized for some substantive domains but not others. Here we address risky choices through that lens asking whether humans' risk responses dispose them to enter social relationships even when doing so is counter to normative rationality and regardless of whether the “enter” versus “not enter” choice is framed as between gains and losses. Laboratory findings in five sites across three countries provide a positive answer to both possibilities. Participants could enter or not enter inherently risky social relationships. They were more willing to enter such relationships than rational choice models would predict and were equally so willing regardless of whether equivalent alternatives were framed as gains and as losses. With the “social context” extracted in otherwise identical games, participants' risk responses were consistent with prospect theory. The present findings suggest the possibility of adaptations designed to facilitate sociality—despite its risks and how those risks are framed.