Answer:
According to the author, the effect of American attitudes and stereotypes regarding race is that it creates an environment where it is practically impossible for black individuals to believe that the nation is serious about its promise of equality. The author suggests that these attitudes, assumptions, stereotypes, and behaviors contribute to unfair treatment and decisions that harm members of another race, particularly black individuals. The example provided of the young black woman's experience in a Fortune 500 company illustrates the frustration and discouragement she faced due to the lack of representation and opportunities for advancement for black professionals. The author implies that these negative attitudes and stereotypes perpetuate a systemic bias that hinders the progress and success of black individuals in American society.