In 1986, Neisser and his collaborator Nicole Harsch asked a group of undergraduates to recall how they learned of the Challenger space shuttle disaster the morning after it happened. Much like earlier reports, they found that almost all of the students had detailed memories of “exactly” where they were and what they were doing when they found out about the explosion.

Neisser and Harsch did something that other researchers hadn’t done before. They asked participants to recall the same event a few years later. They found that although everyone still had vivid and complete memories, some of the memories had changed quite remarkably. In fact, 25 percent of participants reported different memories altogether, such as first describing having learned from a fellow student in class, and years later saying they saw it on a TV news bulletin with their roommate.

This meant that the vividness and confidence that participants had shown were not related to the actual accuracy of their memories.

And the errors that flashbulb memories develops are not random. Our emotions and sense of belonging to a group can color them. For instance, Neisser was probably listening to a football game on the radio when he heard about Pearl Harbor. He argued that the switch from football to baseball served to emphasize his personal connection to the “national pastime” at a time when that nation, to which he was an immigrant, had been attacked.