An interesting question, as you really are asking about the difference between actually remembering an event versus folk memory. I suspect you should be looking at about 80-90 years after an event. The Second World War is rapidly heading towards Folk Memory. If you served for the last couple of months of WW2, you'd be at least 104 now. In the UK, there are about 2000 people left aged 104 or older. Most elderly people were young children in WW2, and their memories of the events will be flawed, or even reconstructed. Of course in the multimedia age, recordings are made to try and keep alive such memories for school children. I'm not sure that's really any different to books. And I don't really think its a good thing. The post WW2 generation was traumatised; kids without fathers, kids with memories of the absolute horror of war. Continually replaying footage, for instance, of 911, can continually retrigger fear, grief, and anger. Society does need to move on. I'm not sure when its supposed to move on though. When traumatic footage becomes a central element of national or group identity, it can anchor political narratives in victimhood or resentment. A good friend of mine served in Afghanistan, and he recounted a story of meeting an angry elder as he lead a patrol. It was relatively early on, and the British were conducting foot patrols in the towns, trying to win hearts and minds, and were fairly relaxed (no helmets for instance). The old boy was furious, saying the British needed to provide compensation for destroying a market. My friend was worried, what had we done, dropped a bomb in the wrong place, he was about to write out a chit for cash, and needed details. The old boy was referring to an event 150 years earlier, during one of the previous Anglo-Afghan wars. In illiterate societies, memories are kept alive by bitching about an issue over a camp fire. Not healthy. A sense of perpetual victimhood can also be used by those with neferous motives as propaganda; Himmler did this by inventing a concept of the Volk and Teutonic knights; getting people to miss a society that was actually largely fictionalised. We get the same idea with the Scottish Nationalists, when that Braveheart film came out. The city of Stirling erected a statue to William Wallace that was modeled on Mel Gibson. It was ridiculous. In Northern Ireland, the events of the Battle of the Boyne was marked every July. It ends up in fisticuffs. In England, November 5th Bonfire societies end up building bonfires with caravans to represent burning out travellers.
