On December 7, 1941 Japan attacked Pearl Harbor. The government responded to American advances in the Pacific by selecting policies of war rather than policies of peace. Why did Japanese decision-makers choose the path of military confrontation rather than the path of diplomacy? What prompted them to confront the United States at Pearl Harbor? Was it the configuration of the international system, or the capabilities and resources of nation-states that compelled them all to choose war? Or were structural circumstances fluid enough for people to disagree, and for differences among decision-makers to reflect variations in the cognitive costs of making judgments?This paper will review Japanese decision-making dynamics in 1941, and investigate whether structural conditions or the cognitive calculus theory of decision-making best accounts for the foreign policy preferences of individual actors. It will draw attention to deliberations at several levels of government, including within the military services themselves, and consider whether the transparency of American provocations forced all decision-makers to routinely choose force, or if the ambiguity of American actions prompted some people to prefer diplomatic initiatives while others preferred military solutions. In particular, it will explore the proposition that because all individuals are cognitive misers or cognitive processing cost-minimizers who unconsciously prefer judgments that are mentally cheap to those that are mentally dear, differences between civilian and military actors predictably reflect the influence of three different cognitive cost-cutting cues: decision stage (problem definition or solution definition), decision role assignment (leader or advisor), and a decision-makerâs level of substantive knowledge (novice to expert).By examining the evolution of Japanese foreign policy over the course of several months, this paper will not only assess whether and when the cognitive calculus theory of decision-making can offer a most useful explanation for this case, it will address whether the actions of Japanese officials in 1941, like those of British decision-makers in 1938 and American decision-makers in the Cuban missile crisis, the turn toward peace in Vietnam, and the 9/11 responses of 2001 (four cases already investigated), reinforce and extend the power of the theory. It will consider whether the cognitive calculus explanation can account for the preferences of different individual actors, in different states, facing different national conditions, and different international circumstances. This paper will conclude with a discussion of the implications of this work for future scholarly and policy efforts. ..PAT.-Unpublished Manuscript [ABSTRACT FROM AUTHOR]