http://science.time.com/2013/11/19/remember-that-no-you-dont-study-shows-false-memories-afflict-us-all/
Remember That? No You Don’t. Study Shows
False Memories Afflict Us All
Even people with extraordinary memories
sometimes make things up without realizing it
It’s easy enough to explain why we remember things: multiple
regions of the brain — particularly the hippocampus — are
devoted to the job. It’s easy to understand why we forget stuff
too: there’s only so much any busy brain can handle. What’s
trickier is what happens in between: when we clearly remember
things that simply never happened.
The phenomenon of false memories is common to everybody — the
party you’re certain you attended in high school, say, when you
were actually home with the flu, but so many people have told
you about it over the years that it’s made its way into your own
memory cache. False memories can sometimes be a mere curiosity,
but other times they have real implications. Innocent people
have gone to jail when well-intentioned eyewitnesses testify to
events that actually unfolded an entirely different way.
What’s long been a puzzle to memory scientists is whether some
people may be more susceptible to false memories than others —
and, by extension, whether some people with exceptionally good
memories may be immune to them. A new study in the Proceedings
of the National Academy of Sciences answers both
questions with a decisive no. False memories afflict everyone —
even people with the best memories of all.
(MORE: Creating
False Memories in Mice’s Brains — and Yours)
To conduct the study, a team led by psychologist Lawrence
Patihis of the University of California, Irvine, recruited a
sample group of people all of approximately the same age and
divided them into two subgroups: those with ordinary memory and
those with what is known as highly superior autobiographical
memory (HSAM). You’ve met people like that before, and they can
be downright eerie. They’re the ones who can tell you the exact
date on which particular events happened — whether in their own
lives or in the news — as well as all manner of minute
additional details surrounding the event that most people would
forget the second they happened.
To screen for HSAM, the researchers had all the subjects take a
quiz that asked such questions as “[On what date] did an Iraqi
journalist hurl two shoes at President Bush?” or “What public
event occurred on Oct. 11, 2002?” Those who excelled on that
part of the screening would move to a second stage, in which
they were given random, computer-generated dates and asked to
say the day of the week on which it fell, and to recall both a
personal experience that occurred that day and a public event
that could be verified with a search engine.
“It was a Monday,” said one person asked about Oct. 19, 1987.
“That was the day of the big stock-market crash and the cellist
Jacqueline du Pré died that day.” That’s some pretty specific
recall. Ultimately, 20 subjects qualified for the HSAM group and
another 38 went into the ordinary-memory category. Both
groups were then tested for their ability to resist developing
false memories during a series of exercises designed to implant
them.
In one, for example, the investigators spoke with the subjects
about the Sept. 11 terrorist attacks and mentioned in passing
the footage that had been captured of United Flight 93 crashing
in Pennsylvania — footage, of course, that does not exist. In
both groups — HSAM subjects and those with normal memories —
about 1 in 5 people “remembered” seeing this footage when asked
about it later.
“It just seemed like something was falling out of the sky,”
said one of the HSAM participants. “I was just, you know, kind
of stunned by watching it, you know, go down.”
Word recall was also hazy. The scientists showed participants
word lists, then removed the lists and tested the subjects on
words that had and hadn’t been included. The lists all contained
so-called lures — words that would make subjects think of other,
related ones. The words pillow, duvet and
nap, for example, might lead to a false memory of
seeing the word sleep. All of the participants in both
groups fell for the lures, with at least eight such errors per
person—though some tallied as many as 20. Both groups also
performed unreliably when shown photographs and fed lures
intended to make them think they’d seen details in the pictures
they hadn’t. Here too, the HSAM subjects cooked up as many fake
images as the ordinary folks.
“What I love about the study is how it communicates something that
memory-distortion researchers have suspected for some time, that
perhaps no one is immune to memory distortion,” said Patihis.
What the study doesn’t do, Patihis admits, is explain why HSAM
people exist at all. Their prodigious recall is a matter of
scientific fact, and one of the goals of the new work was to see
if an innate resistance to manufactured memories might be one of
the reasons. But on that score, the researchers came up empty.
“It rules something out,” Patihis said. “[HSAM individuals]
probably reconstruct memories in the same way that ordinary
people do. So now we have to think about how else we could
explain it.” He and others will continue to look for that
secret sauce that elevates superior recall over the ordinary
kind. But for now, memory still appears to be fragile, malleable
and prone to errors — for all of us.
VIDEO: The
Woman With No Memory
(An earlier version of this story said that 70% of the
subjects had word-lure mistakes. In fact, 100% of them had a
minimum of eight mistakes each.)