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Stolen " memories investigated

 

Jan. 21, 2006

Special to World Science

 

Memories may be the lifeblood of our identity. To some extent, you

are what you remember.

 

But what if some of your memories aren't really yours?

 

That might just be the case, says a group of psychologists from Duke

University in Durham, N.C., and the University of Canterbury in

Christchurch, New Zealand.

 

In a new study, they seek to understand why some people seem to take

over other people's memories.

 

In past research, the team found that people, especially twins but

others as well, sometimes spar over who owns a memory—and both can't

be right.

 

Thus, " some of the memories in which we play a leading role might in

fact have been the experiences of others, " they wrote in the new

study, published in the February issue of the research journal Genes,

Brain and Behavior.

 

Many twins have noticed the phenomenon for years. But the

researchers, one of whom is a twin herself, say they're the first to

document it scientifically, along with its occurrence among non-twins.

 

In the new research, the psychologists re-analyzed data from their

past studies to try to understand why it occurs. Their finding:

although our appropriation of other people's memories is probably

unintentional, it also tends to be self-serving.

 

People " claim for themselves memories for achievements and suffered

misfortunes but are more likely to give away memories of personal

wrongdoing, " they wrote. That's consistent other recent research

findings, they added, that have pointed to something obvious to many

non-scientists: most of us are often quite selfish.

 

The scientists started the research " in part because of all of the

heat involved in most real world memory errors, " wrote Duke's David

C. Rubin, a member of the team, in an email.

 

Controversy has surrounded the accuracy of memories for decades,

largely because of how witness recollections affect court cases. A

particularly thorny issue has been whether courts should let children

sue their parents on grounds that they recently remembered long-

suppressed memories of child abuse. Some critics contend

these " memories " are often retrieved only with the help of

hypnotherapists, who may actually have planted them through the force

of suggestion.

 

Regardless of who is right, researchers have increasingly recognized

that memories are highly fallible. And Rubin and colleagues say their

findings suggest yet a new way that memories can be distorted.

 

In their new paper, they quoted as follows a typical conversation

between 54-year-old female twins as they participated in one of the

studies.

 

Twin 1: I remember falling over and really hurting my elbow and knee

when a wheel came off my roller skate.

Twin 2: Hang on a minute, are you talking about those roller skates

we got for our eighth or ninth birthday?

Twin 1: Yeah, so what?

Twin 2: Well that actually happened to me if you don't mind.

Twin 1: What do you mean, it was me! I was skating with you and [...]

Twin 2: Yeah, with Marie on the old tennis court.

Twin 1: Yeah, but it was me not you, I remember it being really bumpy

with grassy bits in it.

Twin 2: I think you'll find if you think really hard it was me.

Twin 1: Well I remember it so clearly, and you skated home to get mum.

Twin 2: No, you skated home to get mum, because I was hurt and crying

and couldn't move.

Twin1: Oh well, I guess we get confused; it happened so long ago.

 

The University of Canterbury's Mercedes Sheen, a member of the

research team, wrote in her 2002 Ph.D. thesis: " My own twin and I

dispute a memory over a first kiss at summer camp when we were 12.

The boy in question was the `camp catch,' and although we both

vehemently believe we were the one who was there, the event (one

would hope) only happened to one of us. "

 

Although many twins have noticed the disputed memory phenomenon on

their own, the studies found it may happen more often than they

think, the researchers wrote.

 

A 2001 study involving 20 pairs of same-sex twins uncovered 36

disputed memories, only 15 of which the twins involved already knew

to be disputed, the researchers found. The discovery of a memory-

ownership question " often seemed to come as a surprise to the

participants, and many tried to assert their own right to the

memory, " Sheen and colleagues wrote.

 

The team also interviewed 69 non-twins and found that six reported

having experienced a disputed memory. In half the cases, the

disagreement was with a sibling; in the other half, a friend.

 

In the new study, they analyzed 77 disputed memories gathered in past

research. Most cases involved both members of a pair claiming the

same memory. But some cases—slightly over one fourth—involved

them " giving away " memories, claiming that the other person

experienced the remembered event.

 

Some patterns turned up, the researchers said.

 

First, " the memories are predominantly bad (wrongdoing or misfortune)

rather than good (achievement, gift or daring), " they wrote. Also,

most of the disputes in both twins and non-twins occurred among

females, they found, probably because " women share memories more than

men. "

 

A participant was moreover " more likely to claim good memories for

herself or himself " than bad ones, they wrote. Participants claimed

for themselves 17 out of 18 of the good memories, but only 28 of 43

bad memories.

 

Also, they wrote: " Of the bad memories, there is a very much stronger

tendency to claim misfortunes as one's own (27 out of 34) than

wrongdoings (three of 21). "

 

Thus, in many ways the memories " could be described as self-serving, "

they concluded.

 

They also noted that parents usually were unable to resolve memory

disputes. That was possibly because the conflicts tended to involve

events of middling importance rather than great importance, and the

parents themselves couldn't recall the facts, they said.

 

The researchers said the apparent self-serving nature of disputed

recollections is similar to self-serving tendencies that

psychologists have found in other facets of life.

 

One interesting parallel is with children's imaginary friends, they

wrote.

 

Studies have found that " although the preschool children who were

reported to have such companions normally appear to interact well

with their imaginary friends, they also frequently blame the

imaginary playmate when minor things go wrong, " they wrote. And one

study indicated that " while imaginary companions are often involved

in the child's behaviour, they are rarely praised for their

accomplishments. "

 

Another intriguing parallel, the researchers said, involves dreams.

People sometimes can't figure out whether they dreamt something or it

really happened to them.

 

" These memories of uncertain origin are likewise rather rare and

generally for events of intermediate importance, " they

wrote. " Moreover, those who have such memories often try hard to

resolve their origin in dreams or reality, just as our disputants

expended effort in defending their right to `their' memories. "

 

Scientists have shown growing interest in self-serving behavior in

recent years, and the disputed-memory studies are adding to that

research, according to the team.

 

One 2004 study found that people tend to " attribute their successes

to themselves and their failures to external causes, " whereas a study

four years earlier " showed that people who were confronted with

positive and negative information about themselves later tended to

recall the positive information and neglect or forget the negative. "

 

Brain structures thought to be important in memory formation. The

hippocampus is thought to be central for initial storage of long-term

memories. It also receives strong inputs of information from the

medial septum and frontal lobes, which are responsible for many

advanced cognitive functions including planning and decisionmaking.

Some researchers have also proposed memories may be a form of " mental

time travel " in which the brain returns to a state similar to the one

it was in during the recalled event. (Image courtesy National

Institutes of Health)

 

" Mind-reading " study finds memories are like mental time travel

 

Dec. 22, 2005

Courtesy Science

and World Science staff

 

Humans may dredge up memories by recreating the pattern of brain

activity that occurred when a remembered event first happened, some

scientists believe. The psychologist Endel Tulving has called the

process " mental time travel. "

 

Now, researchers have found that we do much of this time traveling

before the memory actually " resurfaces " to parts of the brain in

which we can talk about it.

 

Sean Polyn of Pennsylvania State University in University Park,

Penn., and colleagues analyzed brain scans from people who looked at

pictures of celebrities such as Bruce Lee and Halle Berry, famous

places like the Taj Mahal and everyday objects such as tweezers. The

participants were later asked to recall as many of the photos as

possible.

 

The researchers found that brain activity patterns associated with

each picture reinstated themselves seconds before the people talked

about them.

 

The scientists were even able to do a little " mind-reading, " they

added, by guessing whether the people were going to remember a

celebrity, place or object from the reestablished brain pattern.

 

The findings are published in the Dec. 23 edition of the research

journal Science. The authors wrote that their technique is " ...a

powerful new tool that researchers can use to test and refine

theories of how people mine the recesses of the past. "

 

The mind-reading capabilities of brain scanning technologies have

been improving, scientists say. A study published last April found

that when people were shown simple patterns of stripes tilted in

different directions, a computer could analyze their brain activity

to figure out which pattern they were looking at.

 

Brain structures thought to be important in memory formation. The

hippocampus is thought to be central for initial storage of long-term

memories. It also receives strong inputs of information from the

medial septum and frontal lobes, which are responsible for many

advanced cognitive functions including planning and decisionmaking.

Some researchers have also proposed memories may be a form of " mental

time travel " in which the brain returns to a state similar to the one

it was in during the recalled event.

 

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