what do sonia's reactions to the polite behavior of raskolnikov's family reveal about her self-concept?

If by "self-concept" you mean Sonya's understanding of herself and her relation to others, then perhaps the best place to begin answering this question is with the disposition of utter humility. Because she has been habituated into a life of a prostitute, Sonya feels awkward when Roskolnikov's mother and Dunya bow to her. She is not used to this feeling of respect.