Transcript for Memory and Forgetting

This is Radio Lab, I'm Chad, I'm Rod. And I'm Robert Crowwich. And today, our program is about memory.

Period. Well, maybe that's because your metaphor is a little outdated, frankly. I think of memories more like a hard drive. Here we are, about to go into B&H. You might find it a tech store? Ah, so much gear. Can you show me your hard drives? Like your brain is basically a biological disk drive.

How big is big these days for a hard drive? And everything you do, everything you see, that I put all the images I've ever seen in my life, could it go onto this hard drive? Somehow, all that experience could store it in your head in some kind of neural code.

Then later, when you want to go back to it, you just find the right file. Good read. Call it right up, but there it is. Top on your computer screen. Your memory. Just as you left.

Never changes.

But again, if you ask scientists about this analogy, they'll tell you.

Well, maybe memory is more creative than that. Creative?

We're reconstructing those memories.

We take bits and pieces of experience.

What feels like a recollection.

Let's begin, simply as we can. What is a memory? Where do you find a memory? Where do you go to find it? There's a scientist, we met Joel to do, works at NYU, who started looking when he was very young in the most obvious place.

This makes a convenient beginning to the story, because perhaps the texture of the brain is very fun to play with. While the young would do had his fingers in the cow's brain, maybe he was also thinking, where in that mess are the cow's memories? These rough membranes over it and just stretch it. Can I touch a memory? Can I pinch it? between my fingers?

In any case, Lidou developed a thing for brains, and many years later in college, he'd get another chance. Taking courses in psychology, but Professor of his asked him to come into the lab. Studying the brain mechanisms. And work on rat brains. And no bullets involved. This time he really would be searching for memories. And I got hooked on it. You with me? Yep. All right. So it was the sixties, right? The dude was in school and it was an interesting time for the field he was about to enter. Scientists had just discovered this drug. They found that if you give this particular drug to, he was probably done in Goldfish first. Yeah, give it to a Goldfish. Squirt a little in the tank. Into the water? Suddenly. The Goldfish can't make a memory. After Goldfish has learned something. They'll smile out and have all kinds of experiences, but later, remember nothing. They won't form a long-term memory. What is the goldfish learn? Ah, actually I have no idea. But apparently they do learn stuff except when they have this drug in their system in which case to learn stuff and forget it immediately. And the implications of this were huge. Oh, yeah, according to a science writer journal there. Absolutely. Because now for the first time scientists could say that a memory

No, because that drug called an SMICEN. The amnesia inducing one. What it does is target proteins.

Well, no proteins, no memory. Well, let me give you an example. Okay, have held this work. And this is something we'll do ended up doing after college. Your methodology, can we start there? Sure. You would take a rat, put it in the box, then play it at a tone. It's the five killer hurts pure tone. It's like, boom, it's up there. Now imagine you're this rat. Your entire world is in this box and suddenly a sound as if from God. And then the sound stops and you're like, what? What is this? Oh! Hey! He shocked me on my feet!

I mean, it's less than getting static electricity. Disguise who works in Lidu's lab. I'm David Bush. He actually demonstrated it for me. All right, so what? Or on me. What I'm gonna do is have you put your fingers on there. Okay. He made me touch the bottom of the cage. I'm putting my fingers on the bottom of the cage. I'm a little scared. Yeah. Yeah. It's really not that bad. It's like static electricity, really. How?

What's the point? Why are we doing this? Oh, well, they're trying to make the rat form a memory. Oh. And here's how we now know that that works. From the rats perspective. The moment it hears the tone and then feels the shock inside its head, a bunch of neurons start to build.

And a connection with what's basically a memory. A memory is a structure that connects one brain cell to another. So the next time that the rat hears that damn tone since inside its brain tone brain cells are physically connected to shock brain cells, it's going to know that after this, Come's this. And so instead of just listening passively, it's gonna freeze. The back is hunched and they're frozen solid. Bracing itself for what is about to happen. Exactly. When we're doing this team C, the rat freeze like that. They know it isn't the midst of remembering. They'll do that the rest of their life.

And so whatever the rat was doing during the injection, it'll never remain.

Ooh, what's that? Wow!

So the basic rule is that if you get to the memory while it's being made, you can bust it up by inserting the structure. So the memory never is actually formed. Right, never committed to memory. But if the memory gets made, and the protein bridge is there in your mind, it's built and built for all time.

Yes, it's about timing. If you get their first, you can erase it, but if you get their after, no. Okay. And that's what everyone thought. Until 2000, one day, Lidu is in his office, and a guy walks in the door.

What do you think would happen if instead of giving the drug while the rat was making the memory? What if, way after the fact we gave it the drug while it was remembering the memory, you remembered something? Could we mess with the memory then?

Yeah, I mean, because the memories are already there, right? You can't erase a memory that is already there. I mean, have you ever seen that movie eternal sunshine in the smallest mind?

Well, that's essentially what it was proposing. Yeah. I mean, it was crazy.

Could we zap a memory that was already there? Could we go in and erase old memories?

Cream said he took a rat, played it at the tone, and he gave them a while to chalk to the feet. So it could form a memory. Tested it, just to make sure and sure enough, when it heard the tone, it froze. Yeah, which means it had the memory good. Then, he waited a long time. 60 days. Yeah. Two months later, he played the rat the tone, and as it's frozen, thinking, oh no, no, no, I know what's about to happen right at that moment, while it was remembering, he gave it the drug.

All of a sudden the rat had been sent back to square one. Now it was like Ooh, what's that? Ow! Memory was gone.

Plus, Joe and others had a concern. Maybe the strike isn't a racing A memory. Maybe it's just giving the rap brain damage.

He wondered, could he pinpoint and extract one single memory of many? So in his latest study, what he did was he taught the rat to be scared of two tones. Not just one. So one's like a... And he teaches the rat to be afraid of both of these tones. Each one results in it. Only this time, when he plays the tones 45 days later, he picks just one of them, maybe for instance this one, to pair with the drug.

So you raised tone one, but not tone two. So do you raise me? You can just erase Ray? That would be the idea. Wow, that really is a eternal sunshine of this pop song.

I think they stole, but maybe they were thinking one of these lines, and they must have read it and been like, oh my god.

How would that work in a therapy situation though?

Relive it. And right as you're talking about it, you swallow a pill? Yeah. More or less. And so in fact, we've done that. They've done that. They have cream-nater networks that McGill University in Montreal, and he has teamed up with a clinical psychologist to try this on people, and it seems. that when you give this drug as a person is remembering or reliving a traumatic event, the memory is eroded somewhat. The next time they think about it, it's not quite as painful.

He says she took the drug while thinking about the trauma. And then a week later, she told the story again. And this time, it wasn't nearly as hard.

Wow. So she went from telling no one about this, including herself, to being so open that she could tell thousands of people.

fundamentally change me. There's an assumption in what you're saying, which is actually kind of wrong. There really isn't anything like a real memory. I mean, think about it. If you can erase a memory while it's being created, that's how we started. And now we learn you can erase a memory while it's being remembered using the same drug. What that really means is that every time you were remembering something, you're actually recreating it. That's the other reason the drug works. And so if you're recreating at each time, then each time you're remembering something, it's a brand new memory.

No. No. That is the crazy implication of this experiment.

And not only is it an act of creation, as Jonah says, cream would say. It's an act of imagination.

That's what scientists say.

This is Yadin. This is Yadin.

Reporter Anne Hepperman tracking down for us.

OK, well, I guess we should go to right now.

Radio lab will continue in a moment.

This is Radio Lab, I'm Chad, I'm Ron. And I'm Robert Krullwick. And today on Radio Lab, we're looking at memory. And, uh, forgetting. Forgetting. Forgetting. And we're looking at how these two processes, remembering and forgetting are intertwined. And writer Andre Codrescu, has an idea about this.

I'm Drika Drescu, with an essay from the book 101 Damnations. Anyways, Robert? Yes. One more. Andre is trying to make a point about his historical amnesia in America and whatever. But what if we were to take what he's saying literally? I think we're to an explorer. Like we know you can subtract a memory, but what if you can add a memory? Like actually add a memory in back into a brain. What do you mean by add memory? In plant the false memory.

Count, okay, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1. My name is Elizabeth Loftus. I'm on the faculty at the University of California, Irvine.

Depending on who you talk to. Elizabeth Loftus is either a hero or a doctor evil. Her research, which goes back more than two decades, has completely changed how we think about memory.

Well, for many

I spoke with her recently about it.

For many years, I and other psychologists were doing experiments in which we distorted the memories of events that people had actually experienced. So we would take somebody who had seen a simulated auto accident or a simulated crime. And we would alter the details in their memory report. We'd make people believe that they saw a car go through a stop sign instead of a yield sign. And we found it was not that hard to alter people's memories of these previously experienced events. But more recently, we've gone even further and shown that you can plant entirely false memories into the minds of people. Memories for things that didn't happen, like what? Well, we planted a memory that when you were about five or six years old, you were lost for an extended period of time in a shopping mall. You were frightened, you were crying. And ultimately, you were rescued. Are you lost by an elderly person? We find you mother. And reunited with the family.

And how did you implant that memory?

We told them that we had talked to their parents and that we'd learn some things that happened to them when they were a child.

They basically interview the subjects about their past. They'd say, hey, do you remember that time when you were on the bike and you fell? No, no, no, they would start with a true story. They'd start with true story and then they'd say, do you remember that time? It was true. Remember that other time? Which was true. And that other time, which was true. And somewhere in the middle of all of those true stories, they would slip in the lock.

The false made up story about being lost and frightened and crying. And in that particular study, we found that about a quarter of our subjects fell sway to the suggestion and they adopted it as their own memory.

Quarter of her subjects, when she checked with them later, now had in their head a memory of being lost and then found in the mall that never happened.

What is happening in this situation is people take their image of an actual shopping center actual family members and they construct an experience out of these bits and pieces. Investigators in this field of made people believe that they had accidents at family weddings or that they were a victim of a vicious animal attack or that they nearly drowned and had to be rescued by a lifeguard, even with these pretty traumatic ideas. You can make people believe that it happened to them.

What I find interesting is why that kind of suggestion worked so well on memory and cream later got we heard from earlier scientists. He puts it this way. Suppose you witness a crime and the police ask you some questions later and they say, did you see a red Camaro leave the scene?

No, didn't see one. But then maybe the policeman asks you again, are you sure you didn't see one? And suddenly you're like, well, I think well, maybe there was, maybe I forgot. You start to question it because as he puts it, when you are remembering something, the memory is unstable. Memory comes back up to this unstable state. It's being rebuilt, recreated. And in that moment, someone without even meaning to consulate something new in.

Yeah, but what's so fascinating to me about that phenomenon, assuming it's true, is that the red Camaro that is now in your head is a vivid technique color. Yeah, Camaro. You can see the light bounce off the hood. It just feels real. You can taste the air.

which is why when someone contradicts your memory says that didn't happen that way. You're like, yeah, it did. Screw you. Well, it's also, it feels like a robbery. Right. They're taking it from you. And in fact, this got Elizabeth lofty sent a line of trouble back in the mid 80s. There were a lot of people. I don't know if you remember this coming forward with repressed memories. Like, I was abused by a shakiness to cult and perform rituals and whatever, all that stuff. We know a lot of those memories were imagined. And she says at the time, she was one of the only people to raise her hand and say, Uh, excuse me. And you got no trouble.

I've never really seen anything like the wrath of hostility when I began to write articles and publish on this subject. It was pretty amazing. The, the vitriol.

What kind of things would they do or say?

Oh, that, you know, my life was threatened. Arm guards would have to be hired at universities where I was being asked to speak. I had the bomb squad at my house on one occasion. One day I was taking an airplane flight and when the woman sitting in the seat next to me learned who I was, she started to swap me with her newspaper. And it was kind of hard to extract myself from her. Because airplanes are crowded places. You know, the fact of the matter is memory is malleable. And we might as well face the truth.

And it's produced by, uh, native meringue.

We will continue in a moment.

Ready? This is Radio Lab. I'm Jada Boomeran.

Yes, radiolab.org. Or go to iTunes. Oh, one more thing home. You can send us an email, too. Please radio lab at WNYC.org. That's the email address. I'm Chad Appamrad. And I'm Robert Willwich. And this was radio lab.