Abstract
This article explores steps toward cross-disciplinary interactions between economics and the behavioral sciences in the second half of the twentieth century. It focuses on Jacob Marschak's professional biography to illuminate how these interactions shaped the relationship particularly between mathematical economists and the behavioral sciences during the early years of the Cold War in the United States. The article examines the conditions under which Marschak was willing to engage with the behavioral sciences movement, the tentative beginnings of collaboration with other behavioral sciences, and its eventual realization. It is argued that the process was marked by ongoing tensions, as mathematical economists struggled to reconcile cross-disciplinary cooperation with their goal of securing the scientific status of economics. While mathematical economists did not outright reject interaction with the behavioral sciences, active cooperation fully materialized only in an exchange of tools and shared methodological commitments.