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A vivid memory
of a traumatic event, right? Well, not exactly. Piaget goes on: "When
I was about fifteen, my parents received a letter from my former nurse
saying that she had been converted to the Salvation Army. She wanted to
confess her past faults, and in particular to return the watch she had
been given on this occasion. She had made up the whole story, faking the
scratches. I, therefore, must have heard, as a child, the account of this
story, which my parents believed, and projected it into my memory."
Piaget was remembering
something he'd been told about, but never experienced. Memory researcher
Elizabeth Loftus has experimented extensively in the laboratory with how
memories can be changed by things that you are told. Your memories are
vulnerable to what she calls "post-event information"--facts,
ideas, and suggestions that come along after the event has happened. You
can, unknowingly, integrate this information into your memory, modifying
what you believe you saw, you heard, you experienced. Over time, you can
integrate post-event information with information you gathered at the
time of the event in such a way that you can't tell which details came
from where, combining all this into one seamless memory.
that you integrate can come from something as subtle as a leading question.
In laboratory situations, Loftus has documented such memory modifications.
After showing a group of college students a film of an automobile accident,
she asked a number of questions about the event. Among other questions,
one group of students was asked, "About how fast were the cars going
when they hit each other?" Another group was asked, "About how
fast were the cars going when they smashed into each other?" A third
group was not asked about the cars' speed.
The students who
were asked about the cars' speed when they "hit" estimated speeds
significantly lower than the students who were asked about the cars' speed
when they "smashed into" each other. A week later, Loftus asked
the students another series of questions about the accident, including
"Did you see any broken glass?" The film had shown no broken
glass, but the students who had been asked about the cars "smashing
into" each other were much more likely to remember broken glass--which
makes sense since an accident at a higher speed is more likely to result
in broken glass.
With the same sort
of questioning, Loftus has led people to believe that they saw a yield
sign where they saw a stop sign, to remember a clean-shaven man as having
a mustache, to recall straight hair as curly.
Maybe that doesn't
seem like such a big deal to you. Sure, the details may be off, but the
basic memory itself is still correct. It's not as though it's a false
memory--like being a secret agent on Mars, say, or having someone try
to kidnap you from your pram.
Mildred Howard. From the collection of Daniel Schacter.
But Loftus's research
doesn't stop there. Working with her students, she has created whole memories,
as detailed as Piaget's memory of the attempted kidnapping. One of her
students provided his fourteen-year-old brother, Chris, with one-paragraph
written descriptions of four childhood events, one of which was false.
(The false event was that Chris had been lost in a shopping mall when
he was five.) Over the next five days, Chris wrote about whatever details
he could remember from all four events, adding details to his "memories."
A few weeks later,
Chris was asked to describe each event and rate the clarity of each memory
on a scale of one (not clear at all) to eleven (very, very clear). The
shopping mall memory got his second-highest rating, number eight. He could
describe being lost in detail.
was told that one of his memories was false. When asked which one he thought
it was, he chose one of the real memories. When told that the shopping
mall memory was fabricated, he had a hard time believing it.
have produced similar results. Dr. Stephen Ceci and his colleagues asked
preschool children about things that had happened to them and, in the
same conversation, about something that had never happened: for instance,
the time they got a finger caught in a mousetrap and had to go to the
hospital to get the trap off. Once a week, for ten weeks, the children
were asked to think hard about the events and try to imagine them. Finally,
the children were asked about the imaginary events.
More than half
the children remembered the made-up events, complete with details about
how the mousetrap got on their finger and what had happened at the hospital.