Thinking over the big single events whose news was widely broadcast, I can only remember the ones that happened once I hit puberty. Perhaps the larger social world isn't so important to us as children, when we're still fairly solitary and socially retarded.
I was barely alive when John Lennon was killed or when Reagan was shot. I have no memory at all of Black Monday, the Tiananmen Square massacre, or the Berlin Wall falling. I have a vague memory of the Rodney King beating, although neither that nor the later L.A. riots stick so strongly that I remember exactly when and where I heard the news.
The first one that I recall pretty clearly is Kurt Cobain's suicide in 1994, when I was 13 and in 8th grade. I was walking down the hall toward the end of the school day (I recall the exact spot), and a girl who knew I and my friends had gotten into Nirvana broke the news. She was widely considered a Nirvana poser, and we never really interacted because of that. We put that aside for the moment, although I still remember feeling a very petty bitterness that she'd heard the news first and told us rather than the other way around. It wasn't fair -- we were ten times the Nirvana fans she was! So works the teenage mind...
After that was the not guilty verdict in the 1995 O.J. Simpson murder trial, when I was in 9th grade. Our high school thought it was so important that they let our teachers table whatever they had planned for the final class period, when they would tell us the news and let us talk about it amongst ourselves, with the teachers moderating. My class got gipped because all we got to miss was gym class. I don't recall anyone getting really incensed one way or the other, although it was such a lovely fall afternoon and we were outside, so probably were not in the mood to argue like those who were holed up in a classroom. I would guess my gym class was 70-80% white, with the rest about evenly black and Hispanic.
And of course I remember 9/11. That was sophomore year in college. Our small syntax class had just ended and we were riding the elevator down together when a black woman, almost panicking but keeping her cool, joined us. Either spontaneously or after we gave her a "what's wrong?" sort of look, she told us that "we've -- been -- a -- ttacked." A Millennial friend of mine, who was 12 and in 7th grade at the time, said she remembered everything about that morning and afternoon as well. I doubt she remembers Kurt Cobain or O.J. Simpson, but I'd have to ask.
I don't have one of those vivid recollections of where I was when I heard the news of the stock market tumbling in 2008, though I remember spending extra time in the library in between classes to check in with lots of newspapers. It definitely has not left the same imprint as the other three.
Does anyone have a distinct "I remember exactly what the context was" memory of one of these big, widely broadcast events that is from your childhood rather than adolescence or later? I believe my mother (and perhaps my father, too) has one of those memories about JFK's assassination, and she was only 8 years old then. Does it take something that extreme? How did kids born in the mid-'60s react, if at all, to Nixon's resignation? Or those born in the early '70s to the Iran Hostage crisis? Maybe these do leave lasting sharp impressions on a child's mind, but they have to hit closer to home than the fall of the Berlin Wall or Tiananmen Square Massacre.
For any social scientists out there, this would be an easy thing to find out by survey. Ask a bunch of people if they have this kind of memory for a list of big events, and ask their birth year. For each event, plot the percent with vivid memories by how old they were at the time. This would reveal when the "sensitive period" is for learning about impactful social events. Even more interesting than when it begins is when it ends -- how many who were 60-somethings at the time had a sharp memory of where they were when they heard John Lennon had been shot? Probably not very many.
Maybe this period of learning lasts only as long as a person's reproductive career, when we have no choice but to be very social and up-to-date with our social information. Before then, we're still maturing socially, and after -- well, we've mated all we're going to, so who gives a shit if we're out of the loop?