The Americo-Liberians had been cut off from their African cultural inheritance by the conditions of slavery, and were entirely acculturated to contemporary Euro-America society. They were of mixed African and European ancestry and therefore generally lighter-skinned than the indigenous blacks. Crucially, they had absorbed beliefs in the religious superiority of Protestant Christianity, the cultural superiority of European civilization, and the aesthetic superiority of European skin color and hair texture.
They created a social and material facsimile of American society in Liberia, maintaining their English-speaking, Americanized way of life, and building churches and houses resembling those of the Southern U.S.
The Americo-Liberians never constituted more than five percent of the population of Liberia, yet they controlled key resources that allowed them to dominate the local native peoples: access to the ocean, modern technical skills, literacy and higher levels of education, and valuable relationships with many American institutions, including the American government.
Ironically, one aspect of American society that the Americo-Liberians recreated was a cultural and racial caste system—however, in this case with themselves at the top instead of the bottom. To them, their society must have seemed radically different from the USA because it rejected the ubiquitous Western belief in immutable racial hierarchy, which had led the colonists to despair of life in the USA. They, on the other hand, believed in racial equality, and therefore in the potential of all people to become 'civilized' through evangelization and education. Like many white missionaries before and after them, they were frustrated by the natives' lack of interest in becoming 'civilized.'
Some local people assimilated into Americo-Liberian society, often by marriage. Some entire coastal tribes became Protestants and learned English. But most indigenous Africans kept to their traditional languages and religions. Before long, the Americo-Liberian ruling elite was living rather prosperously, sending their children to America for (often racially segregated) high school and college education, and keeping the indigenous peoples excluded from all political and economic leadership.