I want to know the basic difference between nostalgia and memory in a diasporic perspective. When does memory becomes nostalgia and vice-versa?
Memory becomes nostalgia when the individual or especially people who are remembering begin to long for a return to the past as they remember it. From a diasporic perspective, this can be a very powerful thing, because it often is a response to oppression, poverty, or at the very least, dissatisfaction with a people's current condition. As such, it can become a powerful political ideology or element of culture. An example would be the development of African diasporic literature, which saw writers putting old stories, many of which dated from Africa itself, into written form. Often, these stories reflected the changes wrought by slavery itself, including Christianization, the assimilation of a number of African cultures into regional ones in the New World, and the effects of the brutality of slavery itself. Sometimes authors created new works that reflected a certain understanding of the past though they might be set in modern contexts. In any case, these stories reflected a longing for (in other words, nostalgia) a homeland that was imagined to be very different than their current situation, and thus could be interpreted as a form of agency for dealing with slavery. Moreover, they were often published at times (Reconstruction, the Harlem Renaissance, the 1960s) when African-American writers sought to assert a new identity different than the one often portrayed by white literature and art.