korrents

korrents · Lex Fridman Podcast · #430

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

Charan Ranganath · 3h 10m · youtube.com ↗

20 korrents from this recording

1h2h3h
Charan Ranganath did not write this page.

Every claim below is a statement made in this recording, quoted word for word and linked to the second it was said, so you can hear it rather than take our word for it. The wording comes from the transcript published alongside the recording; the sentence above each quote is our reading of the claim, not their wording.

  1. 0:13:21 · watch on youtube.com↗

    Our reading

    Adolescence, not the first three years of life, is the period that matters most for how a brain turns out.

    Their wordsI mean, I do feel like adolescence is much more important than I think people give credit for. I think that there is this kind of a sense the first three years of life is the most important part, but the teenage years are just so important for the brain.
    Interesting
  2. 8 min later

  3. 0:21:38 · watch on youtube.com↗

    Our reading

    Memory does not simply decline with age — an older brain's job changes to passing on accumulated knowledge rather than forming new episodic memories.

    Their wordsabout this idea that really when you’re older in most societies, your job is no longer to form new episodic memories, it’s to pass on the memories that you already have, this knowledge about the world, what we call semantic memory, to pass on that semantic memory to the younger generations, pass on the culture.
    Interesting
  4. 8 min later

  5. 0:29:24 · watch on youtube.com↗

    Our reading

    The brain does not record experience continuously; it lays down an episodic memory at moments of surprise, uncertainty and prediction error, because that is where the useful information is.

    Their wordsis this idea that we form these internal models at particular points of high prediction error or points of, I believe also points of uncertainty, points of surprise or motivationally significant periods. And those points are when it’s maximally optimal to encode an episodic memory.
    Interesting
  6. 3 min later

  7. 0:32:06 · watch on youtube.com↗

    Our reading

    The point of a good memory is not to remember more but to remember better, because forgetting most of what you experience is what human brains are built to do.

    Their wordsWhat I say in the book is is that you don’t want to remember more, you want to remember better, which means focusing on the things that are important. That’s what our brains are designed to do.
    Interesting
  8. 4 min later

  9. 0:36:07 · watch on youtube.com↗

    Our reading

    Expertise is not passively absorbing patterns — it is learning what to look for, which makes becoming an expert a training of attention.

    Their wordsThis fits with some of the studies of chess experts and so forth that it’s not so much that you learn the patterns passively. You learn what to look for. You learn what’s important and what’s not.
    Interesting
  10. 1 min later

  11. 0:36:53 · watch on youtube.com↗

    Our reading

    Memory athletes were not born with extraordinary memories; they practise a handful of strategies until deploying one is automatic.

    Their wordsBy all accounts, from people who become memory athletes, they weren’t born with some extraordinary memory, but they practice strategies over and over and over again. The strategy that they use for memorizing a particular thing, it can become automatic, and you can just deploy it in an instant.
    Interesting
  12. 3 min later

  13. 0:40:03 · watch on youtube.com↗

    Our reading

    Forgetting names is not a defect of memory: a name is an arbitrary label with nothing to attach it to, and arbitrary material is exactly what brains are worst at.

    Their wordsFor the most part, it’s like these names are just utterly arbitrary, so you have no thing to latch on to. It’s not really a thing that our brain does very well to learn meaningless, arbitrary stuff. So what you need to do is build connections somehow, visualize a connection, and sometimes it’s obvious or sometimes it’s not.
    Interesting
  14. 6 min later

  15. 0:46:17 · watch on youtube.com↗

    Our reading

    Spacing study out beats massing it: half an hour today and half an hour a week from now is retained longer than two half-hours in one day.

    Their wordsif I just try to do half-an-hour and then later in the day I do half-an-hour, I won’t retain that information as long as if I do half-an-hour today and half-an-hour one week from now. So doing that extra spacing should help me retain the information better.
    Interesting
  16. 2 min later

  17. 0:48:04 · watch on youtube.com↗

    Our reading

    Spaced recall works by stripping a memory of the time and place it happened, which is why the memories you revisit most feel like facts you read rather than things you lived.

    Their wordsSo if you remember this information in different times in different places, it’s more accessible at different times in different places because it’s not overfitted in an AI way of thinking about things. It’s not overfitted to one particular context. But that’s also why the memories that we call upon the most also feel like they’re just things that we read about almost.
    Interesting
  18. 3 min later

  19. 0:50:51 · watch on youtube.com↗

    Our reading

    You only retain what you were pushed to your limit on: if learning feels like coasting, you are not learning.

    Their wordsSo that’s why I think this is a thing that I come back to over and over again, is that you will retain information better if you’re constantly pushing yourself to your limit. If you are feeling like you’re coasting, then you’re actually not learning
    Interesting
  20. 6 min later

  21. 0:56:43 · watch on youtube.com↗

    Our reading

    Remembering is an imaginative construction: we do not replay the past, we reassemble a plausible version of it out of fragments.

    Their wordsSo what he concluded was that he called remembering an imaginative construction, meaning that we don’t replay the past, we imagine how the past could have been by taking bits and pieces that come up in our heads.
    Interesting
  22. 48 min later

  23. 1:45:05 · watch on youtube.com↗

    Our reading

    There is no such thing as a true or a false memory: every memory is a mix of fragments of what happened with the theories and inferences we used to fill the gaps.

    Their wordsWell, I like to say there’s no such thing as true or false memories. It’s like Johnny Rotten from the Sex Pistols, he had a saying that’s like, “I don’t believe in false memories any more than I believe in false songs.” And so the basic idea is that we have these memories that reflect bits and pieces of what happened, as well as our inferences and theories.
    Interesting
  24. 9 min later

  25. 1:54:25 · watch on youtube.com↗

    Our reading

    A group with a dominant talker remembers less and remembers his version; giving every member a turn is what makes a shared memory accurate.

    Their wordsOne situation is you have people who are very dominant, who just take over the conversation. And basically what happens is the group remembers less from the experience and they remember more of what the dominant narrator says.
    Interesting
  26. 2 min later

  27. 1:56:30 · watch on youtube.com↗

    Our reading

    The thing to fear about a new technology is not the technology but the maladaptive ways people adapt to it — with AI, what people will do, not what AI will do.

    Their wordsI think a lot of the problems that come up with technology aren’t the technology itself, as much as the fact that people adapt to the technology in maladaptive ways. I mean, one of my fears about AI is not what AI will do, but what people will do.
    Interesting
  28. 10 min later

  29. 2:06:07 · watch on youtube.com↗

    Our reading

    Torture and enhanced interrogation produce what the interrogator wants to hear rather than what happened, because stress shuts down the machinery that checks a memory's accuracy.

    Their wordsAnd from what I understand, the research actually shows that they just produce what people want to hear, not necessarily the information that is being looked for.
    Interesting
  30. 12 min later

  31. 2:17:51 · watch on youtube.com↗

    Our reading

    In a monotonous stretch of life the days crawl and the weeks vanish, because the sense of how much time passed is built out of what you can remember happening.

    Their wordsAlmost everyone in the class said that the days were moving by slower. Then I would say, “Okay, so do you feel like the weeks are passing by slower, faster, or the same?” The majority of them said that the weeks were passing by faster. According to the laws of physics, I don’t think that makes any sense, but according to memory, it did because what happened was people were doing the same thing over and over in the same context.
    Interesting
  32. 5 min later

  33. 2:23:04 · watch on youtube.com↗

    Our reading

    Nostalgia is a selective reading of the past — useful when it makes you happy now, toxic when it narrows what you can see of the present.

    Their wordsIt’s just this idea that people have about the past can be very useful if it brings you happiness in the present, but if it narrows your worldview in the present, you’re not aware of those biases that you have, it can be toxic either at a personal level or at a collective level.
    Interesting
  34. 17 min later

  35. 2:40:00 · watch on youtube.com↗

    Our reading

    Having both episodic and semantic memory is what lets a mind change on a dime without erasing what it already learned, and it is why humans can learn from so little data.

    Their wordsSo it gives us this enormous amount of flexibility to stop on a dime and change, without having to erase everything we’ve already learned. And that solution is incredibly powerful, because it gives you the ability to learn from so much less information, really, and it gives you that flexibility. So one of the things I think that makes humans great is having both episodic and semantic memory.
    Interesting
  36. 8 min later

  37. 2:47:39 · watch on youtube.com↗

    Our reading

    We have not replicated human intelligence until a machine makes the same characteristic mistakes people do — making different mistakes is not the same as being intelligent.

    Their wordsI don’t think we’ve replicated human intelligence, unless I know that the simulator is making exactly the same kinds of mistakes that people do, because people make characteristic mistakes. They have characteristic biases, they have characteristic heuristics that we use, and those have yet to see evidence that ChatGPT will do that.
    Interesting
  38. 7 min later

  39. 2:54:33 · watch on youtube.com↗

    Our reading

    Task-switching destroys memory by chopping an experience into artificial event boundaries, so you spend the whole session catching up instead of building a model.

    Their wordsIt just kind of vanished, because what happens, I’m creating all these artificial event boundaries. I’m losing all this executive function every time I switch, I’m getting a few seconds slower and I’m catching up mentally to what’s happening.
    Interesting