Wednesday, August 19, 2009

Can you trust your memory?

Sandra Parshall

Forget everything you ever believed about memory.

Neuroscientists have decided they got it wrong the first time around – instead of being hardwired into the brain, unchangeable, a memory is dynamic and can be distorted or drastically altered by current experiences. There may be no such thing as a totally accurate memory.

Of course, ordinary people have always known that we have gaps in our memories, that we sometimes “misremember” things, but we don't seem to doubt the accuracy of the memory itself; we just assume our conscious minds are having trouble accessing it. Police and prosecutors have always known that eyewitness testimony is unreliable – question 20 witnesses to a crime and you’ll probably get 20 different accounts of what happened and what the perpetrator looked like. Yet the human faith in the rock-solid truth of memory is so strong that juries send people to prison solely because eyewitnesses have identified them, and we argue to the point of blows over “what really happened” during a pivotal event.

Until a few years ago, neuroscientists believed that once a memory was physically implanted in the brain, there it stayed in its original form unless destroyed by disease or injury.

The flaw in the old theory of unchanging memory became obvious in the early 1990s when a startling number of people began recalling “repressed memories” of childhood sexual abuse. After a while the situation resembled the Salem witch hunt, which is now considered a sort of group hallucination. Families were torn apart. Innocent people were branded as pedophiles. Some of those memories of abuse may have been real. Some may have been knowingly fabricated. But many were apparently planted in vulnerable minds, however unintentionally, by therapists. A few people heard and read so much about repressed memories that they started believing they’d been abused as kids too. If the false memory of horrifying events could be created by suggestion, what other manipulations of memory were possible?

My own fascination with that question resulted in my first published novel, The Heat of the Moon. Until the final title popped up while I was writing Chapter 11, the book’s working title was Memory. It’s interesting to note that one editor who rejected the book said she simply didn’t believe that anyone’s memory could be manipulated.

That editor’s opinion aside, hundreds of experiments and studies in the past decade have led to the same conclusion: memories are highly malleable, they have a lot in common with imagination, and we are constantly revising them. The more often we recall an event, the more likely we are to embroider it with imagined details, and because it’s so clear in our memories, we’re certain it happened exactly that way. (Hillary Clinton’s account of leaving a plane under nonexistent sniper fire, a story she obviously believed, is a perfect example.)

A memory is a chemical reaction in the brain, involving more than a hundred proteins. Electrical impulses (aka sensory information – sights, tastes, smells, etc.) set the process in motion, and the thing we call a memory ends up in the amygdala, which is the size of an almond, and the tiny, banana-shaped hippocampus. Everything we have ever experienced, thought, desired, feared – everything that makes us who we are – resides in these astonishingly small storage spaces inside our skulls. But we frequently haul out our memories, handle them, share them, expose them to our current experiences, and every time we access them we may change them slightly. Our emotional state today can alter our memories of what happened years ago.

All this may create problems for a prosecutor who needs reliable eyewitnesses, but it may offer a way back to peace of mind for combat veterans, rape victims, and others tormented by post-traumatic stress disorder. Every recall of a frightening memory sets off a chemical reaction in the brain that can reinforce or magnify the original terror. But what would happen if the mind were prevented from making all the chemical connections that produce fear?

A few psychiatrists and psychologists who treat patients with PTSD are taking a new approach based on a better understanding of how the brain processes memories. They give a patient propranolol, a common, safe medication for high blood pressure that also happens to block some of the chemical reactions in the brain that reinforce frightening memories. While the patient is on propranolol, he deliberately calls up the traumatic memory, but because propranolol prevents his brain chemistry from going haywire, he is able to remember the entire experience more calmly. After a series of such “treatments” most patients are no longer at the mercy of their past traumas. Will the benefit last? At this point, no one knows, but if it does, it may lead to new ways of treating anxiety disorders, phobias, even addictions.

Our memories tell us who we are and where we came from. An amnesiac – or a victim of Alzheimer’s – has no identity. Because our memories are essential to our sense of who we are, it’s more than a little scary to admit that they aren’t totally reliable. It’s always disconcerting to find that someone who shared an experience with us remembers it in a radically different way, with details we don’t recognize. With so much scientific evidence of the memory’s malleability accumulating, though, we may have to admit that each of us sees the past through a distorted filter. If researchers could give us a foolproof way to remember where we put our car keys, all the rest might be easier to swallow.

How would you rate your memory? Have you ever argued with your spouse or a friend or a sibling about your differing accounts of an event or a place? Have you ever been shocked to find proof that something you remember vividly didn’t actually happen?


Lonnie Cruse said...

That IS scary! I remember seeing a news account of a woman who'd been involved in an accident in her car and permenantly lost her short term memory She could remember her children when they were little but not that one of them had died recently, so every time she asked about him, she heard the news as if it was new. That would be impossible to live with.

Yes, it's easy to manipulate memory AND to argue with someone else about what happened when, or who said what. Great post!

Julia Buckley said...

My sister and I have similar memories of childhood--that is, we "remember" the same stories and events--except that often she is convinced the event in question happened to HER and I am convinced it happened to me.

I'm guessing we reminisced enough about certain stories and then we both internalized them, and suddenly they became the "memory" of both of us.

So now I don't really trust old memories. They seem to have become distorted along the way.

Sandra Parshall said...

Julia, researchers have done experiments with "implanted" memories and shown that it's possible to make people believe something happened to them even though it didn't. In a widely publicized experiment, subjects were given written descriptions of several incidents that really did happen to them when they were kids, along with one that was fictitious. Afterward, about a fourth of them had already incorporated the false incident into their "memories" and believed it had actually occurred. I'm sure quite a few people believe they watched on live TV as the planes hit the Twin Towers, when all they've seen are the endless video replays.

Anonymous said...

Please update yourself. The idea that "Families were torn apart" and "innocent people were branded as pedophiles" because of so-called false memories is outdated and misleading. Not only is there evidence that many of the accused are guilty, but some of the people who began the False Memory Syndrome Foundation have publicly stated things like 'Pedophilia is a normal part of God's will' and that children ought to be taught that in other countries incest is no big deal. In addition, there are countless studies which prove that some people who have been traumatized as children can and do repress it. There are also confessions from abusers in repressed memory cases.

Total amnesia for child sexual abuse happens in at least ten percent of victims.

Anonymous said...

There are some advocates for further medication treatment of post-traumatic stress. There are some experimental drugs that can—in theory—wipe out the memory. The most extreme view is that all soldiers should be given a chemical mind wipe as part of returning from a war zone. A big problem is that they would not only lose the traumatic memories, but likely lose the combat skills they learned. One possibility would be that all soldiers would be at the skill level of just getting out of basic training all the time if this was done.

Sheila Connolly said...

Fascinating post, Sandy. I've always wondered how our brains distinguish between memory and fantasy, both of which can be vivid and detailed. And what about writers, who visualize whole worlds in their heads? (Don't tell me there's a pill that helps!)

I will say my husband and I have very different memories of who decided to buy a house and have a child. He claims credit; I disagree.

Lyn said...

Fascinating post, Sandra. I remember (LOL) when all that "repressed memory" stuff came out. At that time the groups marketing that idea had made is sound as if every body had repressed memories of being abused. I searched and searched my own memory and came up with nothing remotely abusive, which made me feel, at the time, completely abnormal.

I know a woman whose memory slides with political correctness. I've developed a hobby. Every year I ask her why she did X. Her answers vary according to the prevailing winds. It's wildly funny and sad at the same time. Odd.

Next you'll be telling me that one day our CDs will start dropping bits!

Barbara said...

This is partly what my next book is about. Imagine being a rape victim who identifies your assailant and years later becoming convinced after the conviction is overturned you were wrong. It has happened. Often.

Your anonymous comment is interesting. Still controversial, I guess, but you're post is correct, though some of the problems arose out of investigative and prosecutorial misconduct (some of it no doubt unintended and even well-intended). That strange eruption of prosecutions involving Satanic ritual abuse from the mid-1980s into the 1990s is what my first book was about. An FBI report on the phenomenon found no compelling evidence that any of these crimes were committed for the purpose of satanic practices, yet one poll at the time found 70% of Americans believed these crimes were happening. The author of the report was mostly concerned that real abuse would go unprosecuted because the investigations would pay attention to things other than solid evidence of a crime.

A psychologist at my college teaches a course on this and does research in this area. It's fascinating.

Walt said...

In the cases in which I was involved, knowing the doubtfulness of my memory after a time, I wrote down my impressions of what happened and the descriptions of the perps while waiting for the police.

In one case, my description included the fact that one of the actors was wearing green jockey shorts (nothing sexual, just stupidity and booze). After I identified them through the crack of a door at the station, the sergeant walked in the next room asked the one guy to drop his drawers -- green jockey shorts. The sergeant thanked him and the guy was off to beautiful downtown Richmond for four years.

In another, the attempted rapist reminded me of a character actor who was in a soap opera that was big at the time (people tend to remind me of others, one of my uncles looked like Bogart, another like Elvis, and a third like Joey Bishop). I told the woman detective that the guy looked like a rough version of the actor. Her reaction was, "You mean the guy on (name of soap opera)?" Yep. She used the description and a patrol wagon spotted him on the other side of the river. When she drove me over to make the identification, she looks in the back of the wagon, turns to me and says, "Damn, he does look like (actor)." As a further note, when the uniformed officer driving the wagon, a woman, learned exactly what her collar was wanted for, she shook her head and said, "That slime's in my truck? Hell, if I'd known what he was wanted for, he would have resisted arrest!" Maybe Kipling was right about the female of the species.

I remember a test run years ago in which subjects were shown a drawing of a confrontation on a city bus. In it, a well-dressed African American man is holding up his open palm. Across from him a poorly-dressed white man points at the other's face with his left hand and holds a switch-blade in his right. Later when asked to describe the picture, most of the subjects (who were of mixed genders and races) answered that the African American man was shabbily dressed and menacing the white man. Something to think about when dealing with eye-witnesses.

Sandra Parshall said...

All of your comments are fascinating. Sheila, why would any writer *want* a pill to fix her tendency to create imaginary worlds? I certainly wouldn't take that medication. :-) I heard the editor Nan Talese say in a public radio interview a couple of weeks ago that the fictional worlds her writers create are more real to her than the life she's actually living. She said her husband, the writer Gay Talese, contends that she won't believe anything is real unless she's read it in a book. I suspect a lot of fiction writers are like that.

I think the inability to recall a traumatic event is called dissociative cognition. (I call it a blessing.) The trauma may be so great that the memory isn't fully or accurately implanted in the brain.

If a "repressed" is causing emotional turmoil and preventing a person from functioning normally, how repressed can it actually be? The person must be remembering it on some level. I don't think mental health professionals all agree yet on the topic of repressed memory, so it's hardly surprising that lay persons have differing opinions. I don't believe it's helpful to anyone to declare that all "recovered" memories are real, any more than it's helpful to declare they're all false.

Sandra Parshall said...

I've observed many times that people tend to "rewrite" memories to fit with their basic attitude toward life. It's the half-full, half-empty glass thing.

Paul Lamb said...

And now it seems that we can't even trust DNA evidence at a crime scene. Even that can be doctored.

Gink said...

Like everyone else I am fascinated by memory and the fact that I have what I know are false memories, no matter how real they seem to me. When I was a small child my parents lived on a non-working farm. There was a barn on the property and my sister and I have very strong memories of sliding down the hay chute from the loft. However, both my parents tell us there was no hay shoot, no way up to the loft and even if there had been they never would have let a 3 year old and 4 year old play there! But both my sister and I remember that hay shoot clearly!

Sandra Parshall said...

Gink, the nice thing about a pleasant memory is that you can enjoy it even if it isn't real.


Intriguing and scary at the same time.

The information you provide may explain why one of my brothers remembers his childhood in a totally different vein than the rest of us. At the very least, it's a kinder way of looking at him...

June Shaw said...

This is frightening! Thanks so much for sharing such interesting info, Sandy.

Cher'ley said...

This is funny. One time a lady had tried to get a Coke and lost her money in the machine. After her, I put my money in and got a Coke and her money. I wanted to find her to give her back her money. I told my husband what she looked like. A medium-sized, blonde haired woman, no glasses. After a few minutes I spotted her. I said, "There she is." My husband said, "What?" The woman I pointed to was short, heavy-set, dark-haired, glasses-wearing woman. LOL

Cher'ley said...

My youngest brother remembers getting the tip of his finger cut nearly off when he was in the first grade. I was in the sixth grade and rode to the doctor with him to get it stitched up, however, I could swear it was my next to youngest brother. I remember the pain on his face and the amusement we both got from the gym teacher passing out.

This was just recently discussed and I haven't had a chance to ask my other brother if he remembers it.

Of course we all have different views of our lives as children, but that's the only big difference I remember of an event.