Some people have an amazing ability to recall specific events, like exactly what happened on a particular day decades ago. For example, when one person with such so-called highly superior autobiographical memory (HSAM) was asked what happened on October 19, 1987, she quickly replied that it was a Monday, “the day of the big stock market crash and the cellist Jacqueline du Pré died that day.”
Yet even people with exceptional recall are as susceptible to being manipulated by false memories as the rest of us, according to new research released today in the Proceedings of the National Academy of Sciences (PNAS). The results could have enormous implications for legal proceedings, and any other forum that relies upon the memory of witnesses.
When a University of California Irvine team led by a graduate student Lawrence Patihis tested 20 super-memory people and 38 age- and sex-matched people with normal memory powers on three different tests known to elicit false memories, the HSAM people performed no better than the others.
HSAM is different from using mnemonic tricks and extensive training to remember the order of playing cards or lists, like those described in writer Joshua Foer’s popular book, “Moonwalking with Einstein.” It’s a natural, and seemingly foolproof, ability, although no one knows how many people have it.
In the test, all the people were asked to read about United Flight 93 of Sept, 11, 2001. Part of what they read stated that “video footage of the plane crashing” was taken by somebody on the ground. In fact, no such video exists.
Yet after reading the material, 20 percent of HSAM people and 29 percent of the other group indicated they had indeed seen the video. In a later interview, 10 percent of HSAM people stuck to their stories. Of the total number of fake details about the crash planted in their minds, there was no significant difference in false memory between HSAM and normal memory participants.
“These people are especially good at remembering news reports,” Patihis told NBCNews. “So we expected zero false memories in that task. But they were similar to controls.”
Super-memory people and the normal memory group also scored about the same on tests using word lists. And when it came to slide shows depicting two crimes followed by a written narrative of the crimes seeded with false details, the HSAM subjects were slightly more susceptible to developing false memories.
This is how eyewitnesses can be influenced by police suggestion or news reports.
“When you think about what we already know about memory in terms of distortions, most people are prone to suggestibility effects,” explained Jason Hicks, professor of psychology at Louisiana State University who studies false memory and human learning.
Recall, Hicks explained, isn’t like pulling a snapshot out of our heads. The brain constructs memories from individual bits of information, and then pieces those bits together to reassemble it when we remember something. But new information is constantly mixing with old and can become incorporated in the reassembled memory.
Charles Brainerd, chair of Cornell University’s Department of Human Development, believes true and false memories reside in distinct memory systems: “verbatim” and “gist.”
“Gist memory, which is our ability to understand and interpret the meaning of our experience, underlies our most advanced human thinking, reasoning, and judgment abilities,” Brainerd said. It evolved to help us survive. “However, because gist memory does not contain the same level of detail about our experiences as verbatim memory, it can be tricked and tripped up.”
People can swear in court, and truly believe, in the accuracy of their false memories. But, as Hicks said, “confidence does not equal accuracy.”
Brian Alexander is a frequent contributor to NBC News and a co-author of “The Chemistry Between Us: Love, Sex, and the Science of Attraction.”
First published November 18 2013, 12:02 PM