Adam, your second comment hints at a phenomenon I call - for lack of a specific name - a "Diaspora effect." Whether this results in more accurate understanding of an event is uncertain, but for many dispersed groups it does focus attention on pivotal events in their national histories and sometimes sharpens the historical narrative about these events over time. I suspect that "national histories" (like the Persian, Jewish, Armenian ones) have a different effect on remembering when they're taught to a diaspora and shared in different cultures than in a home country where they're part of the educational system and referenced by the press and popular culture. If one compares the big events of French social memory (the stuff anthologized in Pierre Nora's books for instance) most of them share a certain abstraction or symbolic distance from emotion that's very different from the passion that people in diasporas express when writing about great events, great catastrophes, in their own histories. I do wonder if reduced emotional intensity of "strong" memories would affect public discourse about traumatic events though.