Charan Ranganath: Human Memory, Imagination, Deja Vu, and False Memories | Lex Fridman Podcast #430

... the act of remembering can change the memory. If you remember some event and then I tell you something about the event, later on when you remember the event, you might remember some original information from the event as well as some information about what I told you. And sometimes, if you're not able to tell the difference, that information that I told you gets mixed into the story that you had originally. So now I give you some more misinformation, or you're exposed to some more information somewhere else, and eventually your memory becomes totally detached from what happened.

The following is a conversation with Charan Ranganath, a psychologist and neuroscientist at UC Davis specializing in human memory. He's the author of Why We Remember: Unlocking Memory's Power to Hold On To What Matters. This is the Lex Fridman Podcast. To support it, please check out our sponsors in the description. And now, dear friends, here's Charan Ranganath. Danny Kahneman describes the experiencing self and the remembering self, and that happiness and satisfaction you gain from the outcomes of your decisions did not come from what you've experienced, but rather from what you remember of the experience. So, uh, can you speak to this interesting difference that you write about in your book of the experiencing self and the remembering self?

Danny really impacted me 'cause I was an undergrad at Berkeley and I got to take a class from him long before he won the Nobel Prize or anything, and it was just a mind-blowing class. But this idea of the remembering self and the experiencing self, I got into it because it's so much about memory, even though he doesn't study memory. So we're right now having this experience, right?

Mm-hmm.

And people are, can watch it presumably on YouTube or listen to it on audio. But if you're talking to somebody else, you could probably describe this whole thing in 10 minutes, but that's going to miss a lot of what actually happened. And so the idea there is, is that the way we remember things is not the replay of the experience. It's something totally different, and it tends to be biased by the beginning and the end. And he talks about the peaks. There's also the, you know, the, the best parts, the worst parts, et cetera. And those are the things that we remember. And so when we make decisions, we usually consult memory, and we feel like our memory is a record of what we've experienced, but it's not. It's this kind of very biased sample, but it's biased in an interesting and I think biologically relevant way.

So in the way we construct a narrative about our past, you say that, uh, it gives us an illusion of stability. Can you explain that?

Basically, I think that a lot of learning in the brain is driven towards being able to make sense... I mean, really memory is all about the present and the future. The past is done, so biologically speaking, it's not important unless there's something from the past that's useful. And so what our brains are really optimized for is to learn about the stuff from the past that's going to be most useful in understanding the present and predicting the future, right? And so cause-effect relationships, for instance. That's a big one. Now, my future is completely unpredictable in the sense that, like, you could r- you know, in the next 10 minutes pull a knife on me and slit my throat, right?