"By asking someone to repeat a story over and over again, essentially you start to see the story unravel," criminal defence lawyer Daniel Brown explained in an interview with CBC's Metro Morning.
Those who say they have lived through trauma, however, are sometimes unable to articulate a coherent narrative owing to the brain's tendency to zero-in on only the most essential elements of what happened.
In general, our episodic memories are "prone to distortions" because they are, in essence, a "reconstruction" of events assembled from building blocks stored throughout the brain. The more we recall any single thing, the greater the chance becomes that we'll remove, or even insert, a block that's not supposed to be there.
A variety of influences can increase the probability that a recollection will contain erroneous bits. Decades of research by renowned American cognitive psychologist Elizabeth Loftus, for example, has shown that simple, well-crafted linguistic prompts can easily lead someone to unknowingly insert or omit false details into the retelling of a story.
That's not to say all memories contain inaccuracies. In fact, generally speaking, the human brain does an extraordinary job of encoding countless experiences every day.
But it would be too overwhelming to retain all of the information we take in throughout our lives. Research suggests that while we sleep, our brains whittle down experiences — not just traumatic ones — into their most useful parts to make more room, like freeing-up space on a hard drive.
More than a dozen universities participated in a survey that asked 2,100 Americans from across the U.S. about their memories of Sept. 11, one, three and 10 years after the attacks. When all was said and done, 40 per cent of participants told stories notably different than the one that emerged from their original answers. Interestingly as time passed, those whose answers changed significantly did not become less confident about the accuracy of their stories. The study is part of a huge body of evidence pointing to the reality that memory is malleable, vulnerable to the curious nature of our own neurobiology.
That doesn't mean we should be distrust it, says Simons, but rather, we should appreciate its limits.
Lucas Powers writing for CBC News