It’s happened to me several times: I’ll be deep in conversation with a group of friends and the discussion gradually shifts into personal stories about 9/11. Everybody takes a turn to talk about their experiences that day — where they were, how they found out, what they were thinking at the time. I had heard of similar conversations concerning the day John F. Kennedy was assassinated, but because I’m too young to have been around that day, I didn’t quite understand it until 9/11 happened.

People in the psychology field call this “flashbulb memory,” and it refers to the phenomenon of how people retain exceptionally vivid memories about significant, emotional events. Because history is always told from memory and people’s flashbulb memories dictate what we know about significant events of the past, historians are understandably interested in the phenomenon. A new study indicates that people tend to remember history-making moments more vividly than personally significant events.