Mary’s importance to the novel stems not only from her death, which represents the clear turning point in Bigger’s life, but from her insidious form of racism, which is among Wright’s subtlest criticisms of white psychology. Mary self-consciously identifies herself as a progressive: she defies her parents by dating a communist, cares about social issues, and is politically and personally interested in improving the lives of blacks in America. Though Mary’s intentions are essentially good, however, she is too young and immature either to commit fully to her chosen causes or to attain a sophisticated understanding of those people she seeks to help.
Mary attempts to treat Bigger as a human being, but gives no thought to the fact that Bigger might be surprised and confused by such unprecedented treatment from the wealthy white daughter of his employer. Mary simply assumes that Bigger will embrace her friendship, as she supports the political cause that she believes he represents. She does not even think to wonder about any of his personal qualities, thoughts, or feelings, but merely seeks to befriend him automatically, because he is black. For a tragically brief moment, Mary seems to recognize Bigger’s discomfort, a sign that perhaps one day she could be capable of greater understanding. Ultimately, however, Mary never gets the chance to perceive Bigger as an individual.
Though Mary has the best of intentions, she treats Bigger with a thoughtless racism that is just as destructive as the more overt hypocrisy of her parents. Interacting with the Daltons, Bigger at least knows where he stands. Mary’s behavior, however, is disorienting and upsetting to him. Ultimately, Mary’s thoughtlessness actually ends up placing Bigger in serious danger, while the only risk she herself runs is mild punishment or disapproval from her parents for her disobedience. She does not stop to think that Bigger could easily lose his job—or worse—if he upsets her parents. Mary unthinkingly puts Bigger in the position of being alone with her in her bedroom, and her inability to understand him and the terror he feels at the prospect of being discovered in her room proves fatal.