Daniel Kahneman: How Do Experiences Become Memories? Nobel laureate Daniel Kahneman explains how our "experiencing selves" and our "remembering selves" perceive happiness differently.

How Do Experiences Become Memories?

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So if memory is reconstructed as Scott Fraser says, then do we really know what memory is?

DANIEL KAHNEMAN: All of us roughly know what memory is. I mean, memory is sort of the storage of the past. It's the storage of our personal experiences. It's a very big deal.

RAZ: This is Daniel Kahneman.

KAHNEMAN: I'm a psychologist. I'm retired from Princeton.

RAZ: A psychologist who also won a Nobel Prize in economics. And I understand economists hold a grudge against you for that.

KAHNEMAN: Look, I mean a few economists felt that, you know, the prize could've been better used than by giving it to me. But by and large, I don't think that people have been very emotional about it.

RAZ: Now, along with economics, Daniel Kahneman has done a lot of thinking about memory - how an experience and a memory of that experience are two different things, which was the focus of Daniel's TED Talk. You start with a story about a man who attended one of your lectures. He said he'd been listening to a symphony.



KAHNEMAN: And it was absolutely glorious music. And at the very end of the recording, there was a dreadful screeching sound.

And he said a very interesting sentence, he said, and that ruined the whole experience. And I thought, oh my God, that's ridiculous.


KAHNEMAN: What it had ruined were the memory of the experience. He had had the experience, he had had 20 minutes of glorious music. They counted for nothing. Because he was left with a memory, the memory was ruined, and the memory was all that he had gotten to keep.

We tend to confuse memories with the real experience that gave rise to those memories.


KAHNEMAN: What this is telling us, really, is that we might be thinking of ourselves and of other people in terms of two selves. There is an experiencing self, who lives in the present and knows the present. It's capable of reliving the past but basically it has only the present. And then there is a remembering self, and the remembering self is the one that keeps score and maintains the story of our life, and it's the one that the doctor approaches in asking the question, how have you been feeling lately? Or how was your trip to Albania? Or something like that. Now, the remembering self is a storyteller and that really starts with a basic response of our memory. It starts immediately. We don't only tell stories when we set out to tell stories, our memory tells us stories. That is, what we get to keep from our experiences is a story.

RAZ: And Daniel Kahnemen actually put this to the test. Back in the 1990s, he found two patients about to undergo a colonoscopy. Patient A's procedure would last 10 minutes, and Patient B, twice that long, 20 minutes. And back in the 1990s, a colonoscopy was very unpleasant. So Kahneman wanted to know...


KAHNEMAN: Who of them suffered more? And it's a very easy question. I mean, clearly Patient B suffered more. His colonoscopy was longer, and every minute of pain that Patient A had, Patient B had and more. But now there is another question, how much did these patients think they suffered, and here is a surprise. And the surprise is that Patient A had a much worse memory of the colonoscopy than Patient B.

RAZ: Why did one patient think they suffered more than the other?

KAHNEMAN: For Patient A, the procedure ended when the patient was in acute pain. For Patient B, the procedure was interrupted when he was suffering relatively little pain.


KAHNEMAN: The stories of the colonoscopies were different and because a very critical part of a story is how it ends - and neither of these stories is very inspiring or great but one of them is distinct - but one of them is distinctly worse than the other. And the one that is worse is the one where pain was at its peak at the very end. What defines a story? And that is true of the stories that memory delivers for us, and it's also true of the stories that we make up. What defines a story are changes, significant moments, and endings. Endings are very, very important.

RAZ: So the memory of an experience, I mean, whether it's listening to a symphony or a colonoscopy, I mean, that can be totally transformed by the final moments of that experience.

KAHNEMAN: This really has a significant effect on what people store. I just actually had that happen to me. We were in Switzerland, a while ago, and we had three days of vacation. And the last day was absolutely glorious and the next day we had the opportunity to go on for another morning. And my wife and I both decided not to.

RAZ: So you decided to cut short your vacation just to make sure that you wouldn't mess it up.

KAHNEMAN: That we wouldn't ruin the memory. I mean, you know...

RAZ: Even though you might have had a great day.

KAHNEMAN: Absolutely.

RAZ: Wow.

KAHNEMAN: Depending on how you look at it, this could be a mistake. It really depends how much weight you want to give to the kind of memory you keep.

RAZ: Why does that happen? I mean, why do we remember things based on what happened at the end?

KAHNEMAN: On the peak and the end?

RAZ: Yeah.

KAHNEMAN: Actually, I think there is a good evolutionary reason for this. You know, if you were to design an animal and you were economizing on how complicated the brain of that animal would be, you might say, well, I want the animal to store the peak and to store the end, and how long the episode was really doesn't matter. What matters is how bad were the threat and whether the story ended well. That's what the animal needs in order to plan the future. To decide whether to have that encounter again or to avoid it at all costs.

RAZ: But what about simple, everyday moments? What happens to those memories?


KAHNEMAN: And the answer is really straightforward: they are lost forever. I mean, most of the moments of our life and I calculated, you know, the psychological present is said to be about three seconds long. That means that in a life there are about 600 million of them, in a month there about 600,000. Most of them don't leave a trace. Most of them are completely ignored by the remembering self. And yet, somehow you get the sense that they should count, that what happens during these moments of experience is our life. It's the finite resource that we're spending while we're on this Earth. And how to spend it would seem to be relevant. But that is not the story that the remembering self keeps for us.

RAZ: But how do we know what's real and what's not?

KAHNEMAN: I don't think you can tell. I mean all of it, you know, is probably to some extent reconstruction, except some reconstructions are better than others. But you are not going to know necessarily whether what you're reconstructing is the reality or is something else. During the Watergate affair, Dean...


JOHN DEAN: I will commence with a general description...

KAHNEMAN: Oh, I forget his first name.


DEAN: ...of the atmosphere that existed in the White House...

RAZ: John Dean.

KAHNEMAN: John Dean.


DEAN: Prior to June 1972...

KAHNEMAN: Now he had very detailed memories, of what happened and the conversations he had with the president.


DEAN: ...I shall, as requested...

KAHNEMAN: But he also fabricated a fair amount.


DEAN: ...which themselves evidence...

KAHNEMAN: And clearly, he was trying to be honest. The fabrication went on inside his memory, and he produced things that just didn't fit the historical record, and that he was quite convinced of.


DEAN: These of course are my conclusions, but I believe they are well-founded in fact.

KAHNEMAN: So I don't think that we can easily tell when we're reconstructing and when we're remembering.

RAZ: It just seems like memory could be responsible for so much conflict, right? I mean conflict between parents and children - or adversaries - people who just have different sense of what is true.

KAHNEMAN: Oh absolutely, because one thing that is very difficult is to have a very clear memory and to realize that it is absolutely untrue. Normally, some memories really have the appeal of a visual perception. You know, when I see things, I normally don't doubt them. Doubting what you see is a very odd experience. And doubting what you remember is a little less odd than doubting what you see. But it's also a pretty odd experience, because some memories come with a very compelling sense of truth about them and that happens to be the case even for memories that are not true.

RAZ: Did you ever keep a journal?

KAHNEMAN: Well, I did when I was a child during World War II. I kept a journal. It was lost.

RAZ: So do you know if your memories as a child are reliable?

KAHNEMAN: That would be hard to tell, because the few memories I have of my childhood I've all rehearsed many, many times. And so, you know, I had an episode that was very important in my life of - or at least in a story of my life as a young Jew. I was seven years old, and there was a curfew for Jews in Paris, where I lived at the time. And I stayed with a friend, past the curfew for Jews - it was a six o'clock, I think, curfew for Jews - and I missed the curfew and I had to get home. And I was wearing a sweater with the Star of David. I turned my sweater inside-out and I went home.

And I met a German soldier. He was dressed in a black uniform, which is the uniform of the absolutely the worst of the worst, those were the SS, you know, they were truly dedicated Nazis. And we were alone in the street in my memory, and he beckoned me, he called me, you know, to come over to him and I did. And I was really quite frightened. And he picked me up, and I remember that I was terrified that he would look inside my sweater and see the Star of David. He didn't. He hugged me. He put me down. He opened his wallet, showed me a picture of a little boy, and gave me some money. So that's one of my more dramatic memories, of a Jew being hugged by an SS. It was quite a remarkable thing.

Now, I think I know where I was, and actually recently I told myself that it would be interesting to go back to that area of Paris. I mean, I think I know the street. I think I know exactly where I was, but I would like to verify whether my memory of what this whole area looks like is actually accurate. That wouldn't tell me whether the whole thing is absolutely as I remember it, because it's a story I've told many times. And even though I have a visual image of that German soldier, you probably have a visual image, too, as I told the story. So I don't even know whether the visual image is the real image as I experienced it or an image that I have recreated because I remember that story.

RAZ: I mean, that's a complicated memory, right? I mean, that's a really complicated story. I don't know, I mean, are you grateful for having that memory?

KAHNEMAN: I am very grateful for having that memory. I mean, but I have infused it with meaning over the years because for me what is very striking about the memory is something that I've carried with me all my life as a psychologist, which is how complicated people are. So that nobody is wholly evil and nobody is wholly good, and he was that, you know, Nazi soldier who for all I know, you know, had murdered people or was certainly willing to murder people. But he had a son whom he loved and he got, you know, touched by watching a boy. People are very complex. And for a psychologist, you get fascinated by the complexity of human beings and that is what I have lived with, you know, in my career all of my life is the complexity of human beings. So that memory is quite important to me.

RAZ: Daniel Kahneman. He shared the 2002 Nobel Prize in economics with Amos Taverski. His full talk is at TED.npr.org. On the show today, memory games. It's the TED Radio Hour from NPR. I'm Guy Raz. Back in a minute.

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