“Dear Dr. McGaugh, As I sit here trying to figure out where to begin explaining why I am writing you and your colleague (LC) I just hope somehow you can help me. I am thirty-four years old and since I was eleven I have had this unbelievable ability to recall my past…”
That was how James McGaugh first met a woman called Jill Price. Price, now 48, has a memory that’s truly as astounding as she claimed. Give her any date in her past and she’ll tell you what day it fell on, exactly what she was doing at the time, and any important events that took place. She knows that Easter Day fell on April 11 in 1993 (she had spaghetti for dinner) and on April 16 in 1995 (it was rainy). She can tell you exactly when the last episode of Dallas aired (5th March 1991) or when Challenger exploded (28 January 1986; a Tuesday). She does all of this automatically, without resorting to any memory tricks or conscious effort.
This ability is known as hyperthymesia, or highly-superior autobiographical memory (HSAM). Price was the first case to be described, in 2006, but after news of her ability broke, McGaugh’s lab was flooded by messages from hundreds of people claiming to have the same gift. Many didn’t check out; several did. HSAM is now a frequent, and often greatly exaggerated part of popular culture, featuring in shows like Unforgettable, House, and The Big Bang Theory.
Still, Price struggles to rote-learn poetry or historical dates. She can never remember what the five keys on her keyring are for. She and other people with HSAM have extraordinary autobiographical memories but in other areas, they have very ordinary weaknesses.
Now, Lawrence Patihis from University of California, Irvine has shown that people with HSAM are also vulnerable to exactly the same sorts of memory distortions that the rest of us suffer. Feed them with misinformation, and even their seemingly perfect memories can be warped and twisted. It’s pretty easy to make them think they saw words they never saw, or that they remember events that never happened.
“We didn’t know what to expect,” says Patihis. “We thought that maybe they have a new way of remembering, a new mechanism that’s different to normal people. But now, we think that they’re remembering in the same fallible, malleable way as everybody else. They’re doing something that gives them high accuracy.”
Even people who can remember what they ate for dinner thirty years ago are not immune to false memories.
We now know that every time we remember something, our memories enter a vulnerable state when they can be easily manipulated, overwritten or erased. The act of remembering isn’t like viewing a permanent recording, but like opening up a computer document—one that you can edit as well as read. This leaves us vulnerable. Present the wrong information at the right time, and you can rewrite someone’s recollections with astonishing ease—even if that someone has a super memory.
Patihis’s team, including McGaugh and memory expert Elizabeth Loftus, compared 20 people with HSAM and 38 people with normal memories. First, they asked the volunteers to remember long lists of words, which related to an absent one. For example, the list might include “rest”, “nap” and “bed”, but not “sleep”. Later, when asked to remember which words they had seen, around 70 percent of people claim that they saw “sleep”. And so do people with HSAM—they’re no better at resisting the pull of the phantom word than people with normal memories.
Next, the volunteers watched slideshows of two crimes—a man stealing a wallet, and another breaking into a car. Forty minutes later, they read 50 sentences describing each event, three of which were subtle lies—for example, “the car thief used a coat hanger”, when he actually used a credit card. The volunteers not only remembered things differently thanks to the misleading sentences, but claimed that they had actually seen the fabricated events in the slideshows. And far from being immune, the people with HSAM were actually more susceptible to the misinformation.
Finally, the volunteers answered a questionnaire about the crash of United flight 93 on September 11, 2001. The questionnaire includes some lies—for example, it mentioned that witnesses on the ground had filmed a video of the crash, when no such footage exists.
When asked later if they had seen the crash video, around 29 percent of normal people said yes but just 20 percent of people with HSAM did. They did better, but a fifth of them still made up some false memories! They weren’t relying on nebulous gut feelings, either; they provided elaborate details about the video they saw, how long it was, and what they showed. “This was a big surprise,” says Patihis. “We thought they’d have no false memories because they’re so good at news events, as part of their autobiographical memory skills.”
These flaws seem hard to square with their amazing abilities, but Patihis thinks that there’s no paradox. HSAM people are very good at remembering things that aren’t usually met with deception or contradiction. “No one comes up to them and says March 2nd, 2001 was a Monday not a Friday,” says Patihis. “In the absence of misinformation, they have fantastic autobiographical memories. When you introduce misinformation, they’d kind of the same as everyone else.”
“It is tempting to think that individuals with HSAM people may possess “photographic” memories that record exactly what happens in the same way that a camera or video recorder does,” says Daniel Schacter, a memory researcher from Harvard University. “But [this study] highlights that they do not retain a literal record of their experiences.”
But the members of Patihis’ team disagree among themselves about how to interpret the results more broadly. Some of them believe that HSAM people are such a special group that you shouldn’t generalise too much from them. Others, including Patihis, believe that everyone’s vulnerable to memory distortions.
“I can’t think of anyone who could possibly be immune,” he says. “In practical situations, like when therapists try to bring up memories, or when police do it for eyewitnesses, the basic assumption is that everyone should be vulnerable to misinformation. So, don’t give anybody misinformation.” (See Mo Costandi’s feature on Elizabeth Loftus’s work on flaws in eyewitness testimony.)
Note: There’s been a lot of talk recently about the need for larger samples and more statistical power in psychology studies. The small number of HSAM people limits how big this study can get, and the team is aware of that. But Patihis says, “It’s not that important in this study because the results were straightforward. It would have been more of a problem if we found no false memories in one group.”
Reference: Patihis, Frend, LePorth, Petersen, Nichols, Stark, McGaugh & Loftus. 2013. False memories in highly superior autobiographical memory individuals. PNAS http://dx.doi.org/10.1073/pnas.1314373110
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