By the beginning of the twentieth century, the hierarchy of social mores that sanctioned stereotyping came increasingly under attack. W. E. B. Du Bois's book "The Souls of Black Folk" linked the subjective self-appraisal of African Americans to their struggle with pejorative stereotyping in his essays about "double consciousness". This inner conflict was central to the African-American experience, "this sense of always looking at one's self through the eyes of others, of measuring one's soul by the tape of a world that looks on in amused contempt and pity". Anticipating social psychology, DuBois had identified a whole sphere of comparative attitudes that allowed for the reinterpretation of the black "mask". While black minstrel performers were once seen as the degraded victims of a racist spectacle, subsequent commentators could now celebrate these culture bearers for creating a subversive space for the advancement of their art and aesthetic. African-American minstrels, Karen Sotiropoulos observed, "did not just attempt to hook audiences with hokum; they subverted and manipulated stereotypes as they struggled to present black identity." This critical perspective has the performers looking over the jeering crowd into the eyes of sympathetic conspirators and giving them a wink to signal their mutual confidence.