We rely on our memory for sharing stories with friends or learning from our past experiences. Yet evidence shows that our memory isn't as consistent as we'd like to believe.
There are countless reasons why tiny mistakes might happen each time we recall past events. And whenever these mistakes happen, they can have long-term effects on how we'll recall that memory in the future.
Take storytelling for example. When we describe our memories to other people, we might ask ourselves whether it's important to get the facts straight, or whether we only want to make the listener laugh. And we might change the story's details depending on the listener's attitudes. It isn't only the message that changes, but sometimes it's also the memory itself. This is known as the "audience-tuning effect", showing us how our memories can change automatically over time, as a product of how, when, and why we access them.
In fact, sometimes simply the act of repeating a memory can be exactly what makes it easy to change. This is known as "retrieval-enhanced suggestibility". In a typical study of this effect, participants watched a short film, then took a memory test a few days later. But during the days between watching the film and taking the final test, two other things happened. First, half of the participants took a practice memory test. Second, all of the participants were given a description of the film to read, which contained some false details. Participants who took a practice memory test shortly before reading the false information were more likely to reproduce this false information in the final memory test.
Why might this be? One theory is that repeating our memories of past events can temporarily make those memories malleable. In other words, retrieving（找回）a memory might be a bit like taking ice-cream out of the freezer and leaving it in direct sunlight for a while. By the time our memory goes back into the freezer, it might have naturally become a little misshapen, especially if someone has influenced it purposely in the meantime.
These findings lead us to wonder how much our most treasured memories have changed since the very first time we remembered them. Remembering is an act of storytelling, after all. And our memories are only ever as reliable as the most recent story we told ourselves.
