After acquiring Puerto Rico in 1898, the United States engaged in a systematic ideological conquest of the Puerto Rican population through the social science textbooks used in the public school system. Textbooks portrayed the United States as a beneficent imperialist power and preached the superiority of US culture, stressing the inferiority of all other contemporary world cultures in 1898-1908. Moreover, the textbooks taught students that their own Puerto Rican culture was inadequate and inferior. The educational practices put into effect by US policy makers were based, in part, on the domestic models used for the education of 'inferior peoples' in the United States. Specifically, those experiments were the models of education used to train and teach freed blacks at Hampton Normal and Agricultural Institute and the Tuskegee Normal and Agricultural Institute, and Native Americans at the Carlisle Indian Industrial School. To ensure American cultural and educational hegemony, patriotic exercises and songs were used to imbue affection, allegiance and loyalty towards the US, its culture and institutions. Further, educational conferences and teacher training programs fostered Americanization, assimilation into the United States culture and de-Puerto Ricanization. The United States hegemonic project during the first decade of its colonial control of Puerto Rico was ideologically, though not culturally successful. In thought and orientation, Puerto Ricans did become 'tropical yankees'.