This research examines Smelser's value-added theory of collective behavior. According to Smelser, six determinants are necessary for the development of a social movement: structural conduciveness, structural strain, generalized beliefs, precipitating factors, mobilization of participants, and social control. As a test of this analytic framework, two Melanesian cargo cult movements and the general history of these movements are investigated. On the basis of a historical and comparative analysis that relies upon both primary and secondary sources, the six factors outlined in the theory are shown to be present. The relevance of these findings for the explanation of social movements is discussed.