Ask people what might constitute the basis of a permanent self, and often they’ll point to their memories. We tend to assume that a memory is like a DVD recording — stable, permanent, and unchanging. But research on memory shows that this isn’t the case. Smithsonian Magazine highlights the work of Karim Nader, who has suggested that our memories are in a state of flux.
Nader, now a neuroscientist at McGill University in Montreal, says his memory of the World Trade Center attack has played a few tricks on him. He recalled seeing television footage on September 11 of the first plane hitting the north tower of the World Trade Center. But he was surprised to learn that such footage aired for the first time the following day. Apparently he wasn’t alone: a 2003 study of 569 college students found that 73 percent shared this misperception.
Nader believes he may have an explanation for such quirks of memory. His ideas are unconventional within neuroscience, and they have caused researchers to reconsider some of their most basic assumptions about how memory works. In short, Nader believes that the very act of remembering can change our memories.
Much of his research is on rats, but he says the same basic principles apply to human memory as well. In fact, he says, it may be impossible for humans or any other animal to bring a memory to mind without altering it in some way. Nader thinks it’s likely that some types of memory, such as a flashbulb memory, are more susceptible to change than others. Memories surrounding a major event like September 11 might be especially susceptible, he says, because we tend to replay them over and over in our minds and in conversation with others—with each repetition having the potential to alter them.
For those of us who cherish our memories and like to think they are an accurate record of our history, the idea that memory is fundamentally malleable is more than a little disturbing. Not all researchers believe Nader has proved that the process of remembering itself can alter memories. But if he is right, it may not be an entirely bad thing. It might even be possible to put the phenomenon to good use to reduce the suffering of people with post-traumatic stress disorder, who are plagued by recurring memories of events they wish they could put behind them.