In a wide-ranging study on the process forming African ethnicities in the Americas, Midlo Hall (2005) challenges the idea of the extreme cultural fragmentation of enslaved Africans. Midlo Hall points out that demographic studies on the Atlantic slave trade have demonstrated the impact of specific African regions and ethnicities on particular places in the Americas. She also criticized theories of transformation for having rejected the notion of the existence of self-conscious groups among Africans on both sides of the Atlantic. According to the author, Africans were the only peoples subjected to a denial of this amplitude (Hall, 2005, p. 49). This perspective has also been defended by other authors (Thornton, 1998, pp. 195-205), who have sought to place Africans and their descendants at the centre of their own histories, thereby refocusing on the question of African heritage, examined, however, within more specific cultural matrices than those suggested by Herskovits.