How did Adichie allow a single story to construct her understanding of other people?

According to Nigerian writer Chimamanda Adichie, letting a single story build her understanding of other people took her to construct prejudice and stereotypes. As a result, it is important to take into account more than one story to avoid creating superficial judgement regarding others. For instance, when she arrives to America, her classmates assume she does not speak English because she is African, and when she goes to Mexico, she realises that Mexicans are highly stereotyped and undermined by the media.