The twinge of fear. When I came across Bruine de Bruin et al 2007 as a cite for the claim that sunk cost lead to bad real-world consequences (not the usual lab hypothetical questionnaires), I felt a twinge or sickness in my stomach - and realized that I had now bought thoroughly into my sunk cost essay and that I would have to do an extra-careful job reading that paper since I could no longer trust my default response.