This article details the influence of Russian psychologist Sergei Chakhotin on the propaganda of the Iron Front, an antifascist organization that resisted the rise of the Nazis in the dying days of the Weimar Republic. Notably the creator of the Three Arrows symbol, Chakhotin espoused theories and methods that used Ivan Pavlov's notion of the conditioned reflex and Fredrick Taylor's theory of scientific management to transform socialist propaganda to better combat the rise of fascism. By scrutinizing Social Democratic Party of Germany (SPD) periodicals and Iron Front propaganda, I argue that Chakhotin's ideas played a crucial role in catalyzing changes in the form and content of street campaigning throughout 1932. Chakhotin provided a scientific lens through which his allies in the SPD could view and understand the mass appeal of the Nazis, as well as the necessary changes in party tactics that were required in the age of mass media, popular spectacle, and emotional struggle.