Final answer:
The literary device used when Dee tells Mama that she does not understand her heritage is irony, highlighting the contrast between Dee's superficial understanding and Mama's deeper connection to their heritage.
Step-by-step explanation:
The literary device used when Dee tells Mama that she does not understand her heritage in the story is irony. Irony is a situation in which there is a contrast between expectation and reality. For example, it is ironic for Dee to accuse her mother of not understanding her heritage because Dee herself is the one who seems to misunderstand the true value and significance of her family's customs and traditions. Dee's changing her name and taking Polaroids can be seen as surface-level engagements with her heritage, whereas Mama and the quilts represent a deeper, more lived and felt connection to their ancestry.