9/11 memory study finds vivid recollections often wrong after one year

Research on how people first heard about the September 11, 2001 attacks suggests that many of those memories, though vivid and long-lasting, are not fully accurate. Psychologists studying these personal recollections, known as flashbulb memories, found that people can confidently describe where they were, who they were with and what they were doing when they learnt of the attacks, even when a significant share of those details is wrong.

The researchers said these memories can endure for decades, but their findings show that confidence does not always match accuracy. They also argue that such memories are important not just as personal stories, but as part of a shared social identity, especially in the case of 9/11 in the United States.

In research launched within days of the attacks, a few thousand people across the US were asked how they learnt about 9/11, who they were with, where they were, what they had been doing beforehand and how they felt. They were also asked how confident they were that their memory was accurate.

The same people were contacted again after one year, three years and 10 years, and the researchers are now collecting their memories after a quarter century. After just one year, about 40 per cent of the details did not match what participants had reported a few days after the attacks. Despite this, people remained extremely confident that their memories were correct.

The researchers gave examples of how these accounts changed. One person said after a year that he was on a train when he heard of the attacks, though he had initially said he was at work. Another person first said she was with her husband, but a year later remembered being with her son. The researchers said these mistaken memories then tended to remain stable over time, meaning what people reported after one year often stayed the same in later assessments.

They said such findings are often met with resistance, as many people believe others may remember wrongly but their own memories are accurate. The researchers said they too believe their recollections of learning about 9/11 are accurate, but, as memory researchers, they know there is a good chance that about 40 per cent of the details they remember are wrong.

The article said psychologists have long known that memory is dynamic rather than fixed, and neuroscientists have identified periods when memories are open to change. In that sense, it is not surprising that memories of 9/11 shifted over time. What surprised the researchers more was that people found it hard to accept that their memories had changed.

They said people often assume that if they feel confident about a memory, it is likely to be accurate. Research generally supports that link, but emotional events can be an exception. Such events may improve memory for a few central details while also increasing confidence, even when recall of many other details is worse.

The researchers added that memories of emotional or important events are often discussed with others, and that this social acknowledgement can strengthen confidence in those memories. They said the high confidence associated with 9/11 flashbulb memories is likely linked to both the emotional impact of the event and the fact that people widely shared their experiences with others.

According to the article, memories people believe to be accurate are more likely to shape identity and influence future actions. For important personal events, memories can shift in ways that present people in the best possible light and help them build a life story that supports their well-being.

The researchers said flashbulb memories are also tied to communities and can help bind people to them. In the case of 9/11, this includes the social identity of being American. They pointed to findings from the 1970s showing that 75 per cent of Black Americans had flashbulb memories of learning of the assassination of Martin Luther King Jr, compared with 32 per cent of white Americans. They also said most Britons have a flashbulb memory of learning of Princess Diana's death, while most Italians do not.

Several studies, they said, underline the social role of such memories. One found that people saw Americans with a flashbulb memory of 9/11 as having a stronger American identity than those without one. Another found that people believed a person's identity as an American would suffer if they lost their memory of 9/11, and that this loss was seen as greater if the person forgot how they learnt of the attacks than if they forgot the attack itself.

The researchers said that when people recall how they heard about 9/11, they are likely telling a story they believe to be true, even if some details are not completely accurate. In their view, those small errors may matter less than the role such stories play in linking people to a wider community shaped by the events of September 11, 2001.