The Cognitive Science of Nationalistic Behavior, presented in this paper, integrates the political sciences of nationalities as invented communities with an evolutionary cognitive analysis of social forms as products of the human mind. The framework is modeled after the Cognitive Science of Religion, where decades of cross-disciplinary work has generated standards, predictions, and data about the role of individual cognitive tendencies in shaping societies. We study the nationalistic calendar as a cultural attractor and draw on cue-based behavioral motivation and differential (...) autobiographical memory systems to explain its appeal to the human mind. Calendrical elements are analyzed in the context of essentialist thought patterns and action representation systems. We conclude with the implications of calendrical thinking on the control of elites who aim to forge and reinforce national identities. This paper lays the groundwork for applying a similar approach to the study of other nationalistic elements. (shrink)