A budding scholarship in the fi eld of international negotiations has turned its attention to the informal level of decision making and the associated norms, communications, and interactions of diplomats and offi cials. In particular, the adoption of informal norms infl uences the course of negotiations. However, in the context of international organizations (IOs), the majority of previous literature on negotiations has privileged formality by primarily modeling formal decision making, observing and measuring votes and vetoes, and studying outcomes (Tollison and Willett 1979). As the study of norms is not new, Finnemore (1996: 325) observes that international law, history, anthropology, and sociology provide examples of fi elds that “have always known that social realities infl uence behavior.” Yet political science scholarship has chosen to favor the study of formalized social norms. Only one of Odell’s (2010) three “islands” or areas of knowledge in the international negotiations literature has incorporated informality. That is, unlike negotiation analysis and political economy, constructivism has embraced the notion of informality because informal norms comprise part of its broader focus on the normative framework surrounding negotiations.