Charan Ranganath (on memory)

Welcome, welcome, welcome to Armchair Expert, Experts. on Experts. I'm Dan Rather and I'm joined by Mrs. Mouse. Hi.

We're all obsessed with memory, I think.

We are. Obsessed, slash concerned. I think generally when people are talking about their memory, they're worried.

Well, because we know, and he says in here, you know, basically not. if you have dementia. You essentially-.

You're losing most.

You keep 20%.

Yeah. We interviewed him and then I went and brought the girls up to set, and then we went to Gold Burger and we ate outside, and then we got home that night and I was thinking about this episode. and then I was thinking like, oh yeah, I can picture when we were in front of Gold Burger and there was three tables and the middle table was three people eating, and I can see them. And how fucking weird is that, that your brain can do that?

There's probably something that was novel about it. that made you remember it, though.

What a mystery. That had happened, but yet I can look at it right now. It's just so weird.

It's very cool.

Anyways, his new book is out now. It's called Why We Remember, Unlocking Memory's Power to Hold On to What Matters. So that's what's great about this. It's not just an explanation of how the memory works, but you know, some prescriptive ideas on how to remember what you want to and be thoughtful and mindful about it. So it was very cool.

He's an objects man.

Oh, my goodness. Oh, so nice.

I play in a neuroscience cover band called Pavlov's Dog.

I love it.

A neuroscience cover band.

And then this is my actual band where I played original music. It was a shoegaze band.

That genre is called shoegaze? Yeah. What does that mean? You look down at your shoes while you're performing?

Well, you have like a whole bunch of effects pedals, like f-boxes and wahs. And so for people who do that, because there's just like all sorts of sound effects and things. And so people will often just look like, where am I going to do this?

Do you need to use the restroom or anything before we start? You do? Okay, perfect.

Oh yeah, let's do that. We don't have a door, so we step out.

Yes, we're going to do a quick step out.

All right, you can come in.

Yeah. That's not my job.

I think it's maybe your job to tell her to.

Probably, but I have a hard time delegating. Okay. I'm going to ask you people to do. Yeah, I'm going to be wrong when you ask me. I think that would be the best way.

No, that's not fair.

She cares more about animals than I do.

I know, but it's your dog. You can be a boss. You can say, hey, do you think you could take Whiskey to the vet? He was crying all day.

My sister works for the family.

She's wonderful.

She's incredible, but because she's my little sister, I really can't ask her to do anything, you know? Yeah. No. We're on year 10 of this.

It's like my daughter, I wanted to pay her to edit my book and just do copy editing. She's just like, hell. no. Yeah. I'm like, I can deduct it from my taxes.

And how skilled were these diagnosers?

I don't know. I think it was the 70s, because, like, what would they have done? Give me speed, maybe.

I don't even know if Ritalin was a thing yet.

So they basically told my parents that I have bad hand-eye coordination and that I had ADHD.

Is that even a symptom of ADHD?

I don't know. I think, actually, I think it is.

It kind of makes sense that it would be because it's a focus.

The brain's working too fast to slow it down to operate the hands?

Well, it's definitely affecting me now because I fell off a skateboard a few weeks ago, broke my arm.

Oh, no. And did you have surgery?

I had surgery, yeah.

You busted the humerus? Yeah. And did you have to get a rod? Clean break.

Clean, break, yeah.

Fuck. Were you on a ramp? I wish. It was the most unsexy. Were you 13 feet above the coping?

It was the most, like, incompetent thing. I could basically say bad shoes, bad pavement, long work day.

Were you using the skateboard at that time for transportation? Yeah. Interesting.

Just to get a little bit of adrenaline after work. It was supposed to be a small amount, a safe amount.

Yeah. Wow.

That has got to be a very painful break.

Oh, I went into shock after it.

I bet. Was that the second biggest bone in your body? Behind, I think, the femur?

Yeah, maybe, like this thing? I have pretty long arms and long legs, so I don't know which one it is. Yeah.

And so how many days on a surgery?

It's about two weeks. I had the stitches removed yesterday.

And how does it feel?

It's sore, but I'm off of painkillers. I didn't stay on painkillers for that long. And I've got mobility thanks to the plate.

That's a big scar.

It would be badass were it not for the steri-strips, you know?

Yeah, yeah, yeah.

I was going to say, I need your advice on getting a good tattoo, because I want to get something that would maybe either complement the badass scar or cover it.

I'm going to go another direction. That in itself is its own tattoo. So if you want a tattoo, get it on the other arm and keep that on display.

I kind of agree. I think it'll look cool.

Yeah, what's my company? I want to start with, Charlie? Scars and Veins. Scars and Veins, yeah.

Speaking of ADHD, if I get back to what I was telling you in the story. So after I finished my book, my daughter started saying, Dad, you totally have ADHD. I'm like, oh, you're going to say this about everybody. And I all of a sudden remembered this thing that just had been buried in my mind, that my mom put me on a special diet with no artificial colors and flavors, and they bought me an Atari, and that was what they could do. So then I started seeing a coach and talking more to my daughter about it.

How does that differ from just being an extrovert and getting energy from social interaction?

It differs in the sense that I could be very easily a blob. But with people, I feel accountability. And with people, I get ideas. Sometimes it's even just if I'm writing in a cafe, having people around somehow makes things flow better. I'm not really linear in my thinking about things.

My children are in elementary school, and of course, many of the kids now have diagnoses. So they give the kids with ADHD fidget toys, spinners. That seems to help a lot. I wonder if you need a certain level of distraction.

I think everybody does. The key is giving people controlled distraction. I don't want to say anything about people saying they have ADHD now, because I don't know enough about it. But I will say that we live in a time where people's habits create a real difficulty in focusing. Because when I got my iPhone for the first time, I remember all of a sudden feeling like any time there's nothing happening, I have to check email, right?

Sure, sure, sure.

Pause in the conversation, I got to check email. And for someone like me, this is really hard. But everybody does this. And they talk about this in the book. At that moment, when you think about checking email, you've already lost the ball.

Yeah, that at best case, you will be hanging on by a thread to understand with full focus. Exactly.

Then what happens is people leave and go, Oh, yeah, I knew all that. But they weren't really paying attention.

Yeah, what was actually said. Well, you say in the book, too, that act of emailing the phone, even grabbing a camera to take a picture, it takes you out of the moment in this way. that impacts how you create a memory.

Absolutely. First of all, we don't see the entire world. Our brain is always economizing. You might feel like you're seeing everything here. But really, your eyes have just moved around a little bit and you're using memory to fill in.

That process you just described, doesn't that nullify the entire point of a memory? When we think about how a memory serves us evolutionarily or how it helps us exist, which is, it helps us understand the present and potentially predict the future. And so if the memory you're drawing, like, oh, right, I was in a room like this talking to another person, but it was like I was on 15 different text messages. There's really nothing to glean from that memory. Wouldn't help you understand the present and or predict what's coming next.

Well, this is where there's some really interesting filtration that happens in the brain. So there's a lot of work in molecular neuroscience about plasticity. We think that there's actual changes in the connections between neurons, the basic computational unit of the brain. And that's what allows us to learn, because I can reactivate some sequence of neural activity that is similar to what's happening here. I can have a conscious re-experience of that.

They'd all be under the umbrella of survival. Like novelty, is exciting because it could mean a new food source. It could mean a dangerous predator. We don't know what it is and it would be very important for us to assess what that is quick.

That's the beautiful thing, because if I'm seeing something that's similar enough to what I already know, I already have the memory for it before it even happened. So why would I tweak all of these neural connections just to get this one little bit? It's more or less the same.

Oh, that's interesting. It's like you're not going to release any of that. that's familiar, because you don't need to.

Unless it's familiar, but at the same time I get a reward out of it. or there's a knife being pulled. Even if it's familiar, it's like, oh, it's that familiar guy with the knife.

But is this why marriages over time get less exciting? Oh, that is... I mean, there's something there. You're not creating the same level of dopamine in a long time relationship because it's familiar. There's no novelty.

I feel like this is a fact with anything in life. So I want to say, first of all, just to my wife, that our marriage is exciting. Is it as exciting as it was in the first two weeks?

I mean, this is well known. You're trading here and now chemicals for dopamine chemicals. You are losing a big bit of your chemical excitement, but you're gaining different chemicals. The here and now chemicals.

Attachment, actually. Serotonin, all these other ones that you hear about. Oxytocin. So what I would say, though, is you do need to kind of find the novelty. And I talk about curiosity.

Is there a physiological component to that? Do we decline in the ways, that we decline every way of having less dopamine, of having less? go, explore, go, find? We must be battling some physiological imperative in this.

I think we do. I don't like talking about it as decline. And the reason I don't is there are factors that happen as we get older. Of course, our ability to remember details, our proactive ability to control information, it does go down on average over time. But I also feel like humans live way beyond reproductive years.

Yeah, it's a very confusing species to study, because in some cases, 65% of our life, reproducing is not relevant.

Yeah. In my field, the narrative has often been you have this period of time as a kid where your episodic memory, your memory for events, is not very good. And it's kind of random. And then you become a young adult and everything's great. And then you pass 30 and you start to decline.

Orcas are so fascinating. It's crazy. We could do three hours on it. I think they are the only ones that have a larger neocortex body mass index than humans. Is that right?

Sorry, I'm going on.

No, no, no. Can we start with. what are the mechanics of a memory? How did they actually exist in our brain? Is it a recipe of chemicals?

We know a lot, but there's a lot of arguments. So the standard view is what's called synaptic plasticity. So imagine you have a neuron. There's a little gap between them, called a synapse. And so imagine you have a big web of these neurons that are connected to each other.

Yeah, I don't know if you read. Behave.

Yeah, I love Sapolsky.

What I loved most about his book was this is such an erroneous division. There is no division between nature and nurture. It is one thing happening at all times.

Yeah, it's all connected. By definition, learning is based on your experience. But genes regulate that learning. My colleague friend, Sam Gershman, has shown that you can get learning in single-celled organisms. They don't have neurons.

Is it the combination that produces a new thing?

Yeah, that's right. But it's also overlapping.

Okay.

So there's an ecosystem of memories with overlapping cell assemblies that are supporting these memories. So there is this kind of infiniteness to it. But at the same time, you're constantly recombining and reshuffling elements of other cell assemblies.

And is that all with the goal of efficiency?

It's super efficient. If you think about it, chat GPT has sort of a photographic memory. Think of the carbon footprint. I don't even think they disclose this information. And it's like estimates of the human brain is 12 to 20 watts.

This process of prioritizing. in that moment. So your brain sees something and it's got a million different options to draw on, right? And then now it's making some high probability prediction. We're unconscious of that, right?

This is, again, one of those things that you could debate. But the general idea would be is that there's inhibitory neurons that are keeping the piece, basically. Because if you don't have enough inhibitory activity, you just get seizures.

I get seizures.

Oh, my God. Okay, so we should talk about this.

Yeah, I'm curious.

I'd be very interested in knowing about your memory experiences from this. We should talk Deja Vu, too.

Yeah, we were just talking about Deja Vu the other day.

I feel like you've talked about this before.

Oh, God, scary.

I find Deja Vu scary.

Yeah, yeah. She's afraid she's going to get trapped.

Let's come back to that. Okay, yeah, Tim. So what happens is there's only so many neurons in a network that are going to be active at a given time because you have this competition that's being mediated by the inhibitory neurons. I hope I'm not losing many of your listeners, but basically the idea is-.

Sometimes you've got to go, who cares?

Okay, so basically it's like you have these neurons, and they're kind of in this cage match of, I want to be activated, I want to be activated. And those are the principal cells that would be thought to carry the information of a memory. And then there's these interneurons saying, well, this one's a little bit more active than this, so I'm going to shut down this weaker one. And so that's what creates this thing, where one memory can pop up, at least in a computer simulation, one memory can pop up and the others get squashed.

Something evaluates the relevancy of the one that popped up.

You do have some control over searching for the right memory. And so this is where you jump from this level of the neurons to brain regions. And so an area that I've really been fascinated with is called the prefrontal cortex. Basically, it's about one third of our neocortex.

And the newest part of our brain.

Yeah. If you look at, for instance, dogs and cats, they have a very small prefrontal cortex. Primates, big. Humans, really big. And so it allows us to say, hey, here's my goal, but it's going to happen about five minutes from now.

You can create a model of the future in your head.

And it's based on a goal. So somebody who has no prefrontal cortex can be very abstract. They can have an understanding of the world, but they don't use. Exactly. They don't use that information.

My explanation of addiction also is that when the amygdala is firing, it has a priority. It can hijack everything else. that's happening. If the amygdala fires in a manner, it will shut down your executive function in the prefrontal cortex. You're going to be reacting much more out of instinct and other things.

No, I don't think it's flawed, but maybe I'll offer some careful context to this. I want to be careful not to be the neuroscience guy to say, hey, this is addiction. It's your amygdala taking over. I think sometimes you could just put labels on these things without really getting into the nuances. But there's actually an interesting interplay between the prefrontal cortex, which is, again, using goals, the amygdala and the hippocampus, which is important for saying this event happened in this particular context, this place and time.

I'm going to go deeper than that. The person that's witnessing what we would say is a trigger, which is a context thing, it's not just that they're observing it. The body starts releasing dopamine. You start actually getting a bit high from the trigger. It's not just, oh, this is my memory.

I would hope not.

Yeah, they probably couldn't do that.

But they do studies of people, for instance, looking at drug cues. So people who are suffering from addictions, who look at drug cues, a picture of a crack pipe. And that's enough to activate the dopaminergic circuitry of the brain. Now, I cannot say for sure.

Dopaminergic. I read Dopamination and the other one. And that word I find to be the hardest word to pronounce. Oh, well, you know. Dopaminergetic.

Dopaminergic.

Dopaminergic. Dopaminergic.

Arrgh. Arrgh. Just think like a pirate.

I wish they could do it with. It's not unethical. The dude's already smoking crack anyways.

Well, I mean, a lot of people would say it is. I think, for alcohol, a little less unethical. If you did a brain scan of someone who is maybe not full addict, but someone who struggled with alcohol.

Have we looked at people's fMRIs when they're intoxicated, like drunk?

Somebody must have done that. So let me get back to context. Yeah, yeah. Sorry. No, no, no.

Stay tuned for more armchair expert. If you dare.

Well, it's even worse, too, because unless you've really mastered the material, being in this high arousal state, especially if you've got high cortisol release, too, it can actually hurt your retrieval of information because you're in this high arousal. So if you were taking Adderall, that can produce a problem, too, because now you're too wired. Actually, that kind of shuts down the prefrontal cortex. So it's kind of damned if you do, damned if you don't. It is context dependent.

Back to the question of the mechanics of a memory. Is it electrical or chemical?

Yes.

That was my hunch.

So part of it is ions, right? And so these ions move and that's producing these voltage changes. But the chemical part is at the synapse. The electrical part is within the cell. And what we record when I record an EEG or do intracranial recordings of people with epilepsy, we're actually recording electrical activity that's reflecting these large scale movements of gobs and gobs of neurons, exchanging neurotransmitters.

What do most people have wrong about memory?

I would say that we're supposed to remember everything and that memory is about a replay of the past. Neither of those are true. Anyone who's been studying most of the details of their experience will be forgotten.

Okay. So A, our memory is not nearly as good as we think it should be. And then, what was the second part?

Oh, that it should be a literal replay.

Oh, right. Like you're watching a recording of it. That's right. What is our capacity as humans, memory-wise, relative to A, other species, and then B, machines?

I love this question. What I would say, first of all, is I try to avoid good and bad memory. Because, again, the implication is somehow, if I'm hoarding a bunch of my memories, that's good, right? But it's not necessarily good. You want to be more selective.

I don't think anyone would suggest there's not enough stuff in there.

I think you've got plates in the bathroom or something like that.

A proverbial 80 pounds of shit in a 10-pound bag in this attic.

But nonetheless, you've got all this open space. Why not hoard, right? Right, right. And, of course, that's the wrong answer. We know that the frontal cortex is very well-developed in humans.

That's semantic versus episodic. Those are our two options in memory. OK. So semantic is like dates, times, places, geography, all those things, the concrete. Yeah.

So let's say I went to that same place, and now there's a different taco stand, and I get food poisoning from it. Maybe not food poisoning, because there's a different kind of learning. Let's just say I had a bad taco. So now I'm going to have to use episodic memory to say, hey, I don't want to go back to that place again, because they've changed this taco stand. But chat GPT is going to take forever to learn this, because it already learned that this is a good place to go to.

Yeah, I was recently reading A Brief History of Intelligence, which is a great book. And it was talking about the breakthroughs, with AI competing in both chess and Go. And what they had to do is completely change how they were deploying that computer. Because originally they thought, well, shit, this computer has the power to actually model out every single move. And tell specifically what is the highest probability of success.

They use deep reinforcement learning for a lot of the stuff. My friend Demis Hassabis at DeepMind has done a lot of cool stuff. Part of the reason why AlphaGo beat the best Go player is because it was doing something a little different than the Go players were doing. Otherwise it would have a lot of trouble. So it is doing something a little different.

Yeah.

Sorry, I have a really quick question, because you were talking about hoarding. There was a revisionist history episode once about hoarders and how strong their memory is. Do you know about this? Like the reason their hoarders is actually connected to memory. That they have, like, a very big capacity for memory.

There's some links to this. So there's a thing called highly superior autobiographical memory that was studied by researchers at UC Irvine and now in other places.

And so, Mary Lou Henner, they over index on OCD as well.

That's right. They can just remember some detail from like 10 years ago.

Yeah. What was the weather like Tuesday, March 5th? Yeah. And then their closet is insanely organized. Yeah.

But that's the opposite of hoarding.

OCD sometimes manifests in hoarding too. You can also see in certain realms of the autism spectrum, there's a thing called memory savants.

This is the original Rain Man in Utah.

That's one example. Yeah. And there's people like Stephen Wiltshire who can like go in a helicopter over a city and then paint this incredibly detailed, almost photorealistic painting of it. And so there's kind of this overlap with OCD related symptoms there that have to do with these kind of obsessions and sometimes anxiety and control.

What's happening with their memories that isn't happening in ours?

We don't know about how different people are. Ours, I don't even know what ours means.

Yeah, you're right.

It's just such a fascinating topic.

But I can't paint a city after looking at, you know, I don't have that ability.

Just in general, you have an area of expertise, let's say. You're looking at different things and somebody's not an expert. And so you can subdivide the world in so many beautiful ways. And so, as a result, your memory for the stuff that you're an expert in will be amazing. Chess experts can remember entire matches.

Another fun one is they put headphones on these Formula One drivers. And they play 20 seconds of the engine noise. And they'll go, that's Imola. turns six and seven. Wow.

What's even more insane is they see that pattern happening in real time.

They also make them drive the course blindfolded. And they drive the course perfectly.

That's who we should study. That's what we've got to get into. You should. They can not only see what's happening now, but they're seeing into the future. They're like five steps ahead.

Is it also helpful to them that, because the experience is quite heightened. With adrenaline and every other great neurotransmitter. Does our memory record better in those situations?

Yeah, it records a little bit. In neuroscience, people will often say better. I would say slightly differently. If you imagine, like a TV, right? You turn up the brightness on the TV.

Okay, this is incredible. This is seven years in the making. I've had this theory forever. I've launched it on a couple of people that we've had in that were neuroscientists. Uh-oh.

I will say no, because I probably would think I do, but I don't.

Okay, so the camera is normally taking a picture 24 frames per second. And when you want to create slow motion in a movie, you actually record at 100 frames per second. But then you play it back at 24 frames per second, and that creates this illusion of slow motion. So my explanation for why everyone who thinks the car accident they were in was like three minutes long, is that in that super heightened state, you are so aroused, you take in so much more data. More smells, more sounds, more everything.

Huh, that's interesting.

Now this negates the whole watching back a video, premise that you stated already.

No, yeah, yeah.

But I'm so curious what this phenomena of thinking time was moving very slow in an accident is explained by. And I feel like that's the comp.

What you're talking about is a phenomenon called time dilation, where essentially it's like time feels bigger than it actually is when you're just in an aroused state. Literally your heart's beating fast, right? And so it's a lot like what you're talking about, which is that essentially you're getting more frames per second. And so, as a result, I can imagine that gives you a different sense of time.

I just feel like we play it back at the same frame rate, no matter what, because that's how we play back memories.

But we probably are not playing it in the sense of playing a recording. Right. We're still getting bits and pieces. Ah, okay. But there's too much stuff there.

I get it, I get it, I get it.

This is total speculation. Yeah, I love it. Probably some time researcher is going to call it. Dax, this is completely wrong. But I think what may be happening is that you've got a lot of this information, and now you get little bits and pieces of that information when you're trying to remember it.

Yeah, you've got to go through all these pieces. And then I saw the seatbelt, and then I saw the airbag. There's just so much stuff.

And so you are imagining it in slow motion. Right. And that is what memory is. It's imagining how the past could have been.

Okay, great, because that's one of my questions. So explain the relationship between imagination and memory. I feel like this will be disheartening for some people.

I think it should be heartening for people, because it's so cool, right? So remember, I was saying this idea of why encode something into memory if you already have it?

Why encode something in a memory?

Evolutionarily, why would you use space for it if it's already there?

That's right. Think of how many times you've probably gone through airport security, how many times you've gone to get a coffee at Starbucks, and you probably walk out and have no memory of anything other than the fact that you went there. There's this general economy that we have in the brain of just grabbing the most important or novel stuff. So as a result, what happens is you get those bits and pieces from memory, and that's a little bit of data that you have. You get some context.

Yeah, yeah. The floor plans are the same generally.

But every house has a different paint color, maybe carpeting versus flooring, wallpaper. So they all have this different surface, but they have a similar structure. And that's how we think events work. So you have this structure of the schema, which is knowledge about events. But then you have this episodic memory, which gives you some color for the paint and the carpeting and all this little decoration that you have on it.

Then, of course, it really begs the question. And I think a lot of people are often questioning this about themselves, which is how much of it is real? Or one thing I, like, you, gave this example of. there was this study where they had people read the description of a house and they asked one group to read it from the perspective of a home buyer. And then they quizzed them about different details and they had a specific set of details that was consistent.

That's right.

It's deeply troubling, right?

It shows this is like polarization at its core. Like we're seeing stuff through a very specific perspective. If only we could switch, we would pick up on details we aren't picking up on.

Yeah, people don't have that as a modus operandi and they should.

I know. It is troubling.

But back to, and you talk about it in the book, our memories are really responsible for our sense of identity. And, as you say, our identity is on shifting sand, quicksand, something like that, which is fascinating. And it's a little bit scary because you don't know which you should trust. I mean, I guess there's some freedom in that, which is at any time. you could probably use your imagination to recall these memories in a different way and find new inspiration.

They are subjective. And it's what I really want people to take away, because there's a lot of work on errors in memory. And there's no question in any scientist's mind who thinks reasonably about the stuff, that memory is literal and photographed back. It's just not. But that doesn't mean it's all mush.

It's very fallible.

And most of the important stuff we do get. I like to say memory is like a painting. It's not like a photograph. So you have that painting over there, both of you. And it's like this.

The conclusion. Yeah, yeah.

The judgment.

The theme.

That stuff is the theory.

How does the mood we are in affect the memory we retrieve in that state?

So when we are in a particular mood, that's part of our mindset. And that's part of the context. It's part of the lens through which we're searching for memory. You have this particular kind of filter that you're using. when you're searching for information and memory.

Listen to sadder music.

Yeah. Then you pull up negative memories, you feel worse. And then you pull up more. And so it turns out to be this kind of filter for your memories when you are in a particular mood.

This also gives a little bit of a scientific backing for the power of positive thinking, I'd imagine, too. It makes it a little less, you know. Whoa, whoa. Whoa, whoa. That's the word I'm looking for.

Well, actually, the funny thing is, on average, people who are not depressed have a positive bias in memory. They tend to remember more positive events from the past. And they tend to reconstruct the event more positively than it really happened. Oh, really? And as we get older, people tend to get more of an optimism bias.

That's a blessing. That speaks exactly to your question.

It is. It really is.

Yeah, yeah. Okay. How are memories different from the feelings we have about them?

The feelings that we have, these emotions, are related to survival system, or the parts of our brain that help us respond to stress or threats in the environment, uncertainty, novelty. And so those will give us a pattern of activation in our brain. Also, peripheral nervous system changes that interact with our brain. People go, oh, well, trauma's in the body. But the brain's a body part.

One of these other erroneous, compartmentalized ways of looking at things.

Those feelings are part of the memory. But the thing is, is that our memory for the context and the details can be split apart from those feelings that give us the vividness of memory. So if you look at people who don't have an amygdala, they don't get that emotional arousal with memories. They don't have an effect of emotional arousal on memory in the same way that somebody does. But they can often remember a lot of the details of an event.

So it feels more vivid, but it's not, in fact, more vivid. Exactly.

So, when you get activation of both the peripheral nervous system but also kind of the survival systems that are kind of making you feel aroused, that becomes part of this immediacy that you get. But that is dissociable. And the reason why I say this is because you can change the way that you frame an event. And that knowledge is separate from that feeling that you get. Sometimes, the feeling people get will give people a sense that this is exactly how it happened.

I suffer from this. We all do. I really trust my memory and conclusion. But it is interesting. I guess the way I could find purchase in a lot of these things that you're talking about in the book is, let's say, two months after I broke up with Bree, my girlfriend of nine years.

That's exactly right. Let's say, 20 years from now, we get together for a beer. You would probably look at me and you'd go like, OK, well, he's aged so much. Not a beer, sorry. Coffee or something like that.

Let's get together for some lines. OK.

Sorry. OK. I just am so horrified.

It's been 20 years. Don't even worry.

Please kill me.

People always.

Well, some people, it would bother. Yeah, yeah.

I used to work in the alcohol treatment program at the VA.

Well, he has a NA beer. So you guys could... There. it is right there.

We could bang back some Ted Seegers. Yeah, yeah. Let's do it.

I will do it. OK.

I'll wear your band shirt and you drink my beer.

So let's say we get together for non-alcoholic beers. Then another year later goes by and you see me. You'd probably go like, oh, he's way older than I remember. Now, if you updated your memory perfectly, I wouldn't be that much older, because it would only be a year since the last time you saw me. So if you updated your memory ideally, then you would actually have less of a sense of, hey, something's new here.

But really quickly, that seems like a function of prioritizing. which impression is more important. Because if I were to now permanently make my image of you at 62, it feels more relevant that I remember my initial for my survival. I could see why the brain prioritizes the initial and cements the initial summation of you. Because we're evaluating whether you're good or bad for us or safe or you're a threat.

The strategy is to split the difference. There's a thing in machine learning called overfitting, where you have some thing that you're trying to learn and you learn too much about it. It actually is bad, because you can't generalize in a good way. So there's a general strategy that you want to have where you want to learn just enough. I mean, imagine if I just got this perfect memory of you right now.

Right.

The nose looks familiar.

Exactly. You know, it's like, oh, that tattoo, I've seen that somewhere before. So you don't want to overfit like that. And so I think that the brain is updating, but it's not updating completely. And then there's also all sorts of interesting, weird things where sometimes you just form a new memory of remembering.

Okay. So that's great. That brings me to now, this is not in your book, but this is something that has plagued me, like the car accident time shift. I have numerous occasions, which generally I'm at my mom's house. I'm flipping through a photo album.

Well, so, and I get this, by the way, from people who go, I remember when I was like six months old. It's like the data says that you do not remember when you're six months old, but you might remember seeing pictures of yourself and hearing stories about when you were six months old. And then the imagination kicks in. You just lose the ability to tell the difference in things that you thought about or seeing a picture and things that actually happened, because they're all just mental experiences when you just activate a memory. And so in your head, thinking about something and remembering something are not all that different.

You pull up now the edited version you last made?

That's right. And it becomes more general and more flexible, more accessible. But at the same time, it doesn't give you that sense of traveling back. It's not like you didn't even realize you had this memory, and then, all of a sudden, you go back to your childhood school, and, boom, it pops into your head.

Again, this isn't in your book or on my questions, but now you've said this, and it made me think of this. What is your overall belief in hypnosis and being able to actually go back in a way that you normally couldn't consciously?

I think that hypnosis is problematic because hypnosis is a very deep state of relaxation, from what I understand. And the problem with hypnosis is basically you're turning off the prefrontal resources, the executive functions, that you need to monitor the accuracy of your memory. So we can be accurate, but it takes time, and it takes a little bit of executive function. So we tend to remember things badly when we're stressed out or tired, not getting enough sleep, kind of like I am now. Except for this.

And those then can also become edited memories that you would recall as if they were the same as any other.

Theoretically, you can form, I mean, well, it's happened, that you can form a new memory.

About something 30 years ago.

About something that never happened. A false memory. Right, right, right.

But in theory, yeah, it happened at eight years old.

But it's just an assembled set of bits of, like, I saw this movie. I recalled this family interaction. You just put it all together into some crazy thing. And people who are more susceptible to hypnosis are more likely to do this.

When you're in a hypnotic state, does it prevent you from doing the thing you just described, which is you can't go back to that place in time. So you adjust that memory to fit into your current context. Under a state of hypnosis, would you perhaps just plop back into the old memory without that ability to update it and make it fit your current context?

That's a really good question.

We don't know.

I have to say I don't know. This is something I like to say a lot, is I don't know, or we don't know. Yeah, yeah, yeah. Because it's like you. don't hear scientists say that enough.

Stay tuned for more armchair expert, if you dare.

Sometimes I am like, did I dream that?

Yeah, sometimes. Occasionally, I'm like, I don't know if I dreamt, this or this happened. But again, once every two months, that happens to me. And you're creating a story every single night that's super detailed. And really you're not confused for the most part.

But there's something bizarre that it's kind of hard to make it real. You know that it's fake because you flew, or I had one the other day where there was a moving photograph. You can hopefully know that that's.

Discern the difference.

Yeah. This is something I think about a lot. So there's all sorts of interesting work being done on dreams right now and memory. And one of the things that people are finding is that dreams aren't just associated with REM sleep. They're associated with other phases of sleep.

And dreaming is a big part of how we create memories, no?

File memory.

The file cabinet analogy. we've heard.

Well, I don't like that one.

I like that, you don't like it.

I guess I'm sort of a neuroscientist, because in neuroscience, there's a view of memory as being very literal. And these kind of like traces and so forth. And you strengthen the traces. But the problem is that works in an animal that has very few memories in its life, like a lab animal. But humans have so many memories.

You're siloed, right? You're siloed. So it's like connecting silos at night. Exactly.

So if I walked into your garage and I saw that you had like a bunch of Costco packages of Cheetos, then the next time I come and I see like a bunch of Costco things of Oreos, at some point during sleep, I can build this larger concept, which is Dax stores junk food in his garage. Right. And so that is a kind of magic that comes out of sleep. And what you see after sleep is often people are more fluent in producing the information. Like, if you're learning a new language, that people are better at producing that information or trying to learn a new piece of music, and you're better at producing that later.

That's a good question. I feel like it depends. When I was doing theater school, I could memorize a whole part in a play and that didn't feel crazy. Now that would kind of feel crazy. Like.

But you can improve on it at a staggering pace. So I had done movies for six years in a row. Then I got on a TV show. In a movie, you shoot 120 pages in four months. On a TV show, you shoot 60 pages in six days.

Well, yeah. You hit upon a few things. One is, you developed a skill. But the other is the importance of meaning. What I tell people, if you want to improve your memory, in other words, you want to remember something that you need and be able to pull it out when you need it, plant cues.

Is that the mental castle idea? When people are trying to remember a long list of, let's say, groceries or something, you can build a...

One word story.

No, no. It's like you would go to this attic in your head and I would put bread at the lamp and bananas at my purse. So then I'm walking around the attic in my head and I can remember it. Like from memory games.

Yeah, it's called the memory palace. Memory palace. Yeah, yeah, yeah.

Castle palace.

Yeah, yeah, exactly. I like castle. better. We should go with that.

This is her further running from her Indian roots. Palace? Yeah, because there was a lot of palaces when we were just in India. Not a lot of castles.

I like it. But, you know, there's also Harold, and Kamara went to White Castle. Oh, you're right.

I guess you're right. That kind of counteracts my point.

I have two things that plague me in the way that you're plagued. They might be the same, but one is repressed memories. Do you believe in them?

Yeah. So the standard view, which I subscribe to, is that repression is this idea that comes from Freudian psychology. These urges that are so unacceptable that you purge them from the conscious mind. And it's just an automatic defense mechanism. Freud once proposed that memories can be repressed by that mechanism of something traumatic.

We kind of worship Paul Bloom and he said he doesn't believe in him. And so we kind of were like, okay, then we don't either.

But this, I like this.

This is a little more flexible.

He's not a memory guy. Right? So this is important.

A trick I heard on set from a camera operator, Scipio Africana, a camera operator has to know people's names more than most. He has to know the stand-ins' names. He has to know all the guest actors' names because he's going to be constantly asking them to stand in different positions. And he said his trick was to stand at craft service in the morning in Loiter. there.

Well, there's a bunch of things. So one thing is motivation and motivational circuitry that like the dopaminergic parts of the brain, for instance, in promoting memory. So that makes sense. The idea of linking it to a goal to the extent that there's a social reward. there is something that probably would make the event more memorable.

There's nothing. inherent.

That's right. It could be Courtney Cox's association. She was Monica and friends. So that name, there's all this competition there. But the creamer gives you a distinctive thing to lock into.

Just the commitment to do it is halfway there, probably.

This is something that I say a lot, which is if you know that 80% of the details in your life or more are going to just vanish, what is the 20% that you want to hang on to? And I don't think we actually have the bandwidth in most of our daily life to think about what we want to hold on to. I lose names before I even have a chance to think that I need to memorize this name. Totally. I never thought about it this way, but it's sort of like the memory palace.

That's what I wanted to ask about. Why music is a full time travel, I feel. We've talked about that before. How, if you hear a song, you can immediately transport back to an old memory. Why is that?

There's a number of factors. Number one is music tends to be on as a soundtrack to our experiences. So it's part of the context that we talk about. that uniquely tells us about a time and place. So I went through a metal phase in late junior high to early high school.

I have you call it as 10 to 30.

10 to 30? Okay, yeah.

That's probably the more accurate. Reminiscent bump.

I'm not good with remembering details. But yeah, so that period of time that we tend to call back upon very often.

Well, and in that reminiscent bump, that's where most of your favorite movies, your favorite books, your favorite music, they all live in that period. And it's so true for myself. Yeah. I think of all of my favorites. Very few of them exist outside of that window.

Because that's when the identity is being formed.

That's when you're really getting a sense of who I am. Another part of it is music tends to be emotionally arousing, evocative, and it's social. We listen to music with other people. And it has a structure to it, too, where that naturally links up different things. But I really feel like the emotion, the social nature of it, and the time-limited part of it.

Oh, he uses that to cue up an era.

Yeah. Wow.

I thought you were going to talk about these Alzheimer's people. Oh, that, too. Yeah, who can just play everything they ever learned musically.

Yeah.

Victims of trauma. This is something we talk endlessly on this show about. And I think this is something conceptually I wrestle with daily. As someone who's in therapy and regularly talking about the past, there is some voice in my head that says, it is time to let that be the past and to not let the first nine years of my life dictate the remaining 90.. There's almost a motive to forget.

Well, remembering traumatic experiences is painful. I hear from people, I get emails from people, there's always people in my audience who say, how can I get rid of traumatic memories? And with the sensitivity to the fact that I get it. But it's like, you don't want to erase the memory. You want to change your relationship with the memory.

That was another one of my questions, but you're kind of incorporating into it, which is how memories that are formed with another person are different and how forming memories together, it's its own thing as well.

I used a statistic that I got from an analysis in the book. I think it was something like 30% of human language is spent basically communicating memories with others. And I would argue that's probably why we evolved language, because I don't have to make mistakes to learn from them. I can learn from your mistakes. And that is this enormous capability that we have language.

Let me put this thought, that's in my mind, into your mind.

And that is creating a narrative that wasn't necessarily there before. And that's now a new memory. That's a new part of your life story. And so these social interactions that we have reshape our memories constantly. And then you think about things that are shared experiences, like we all live through the COVID lockdowns.

Right. Well, it did make me think, often, when I tell my brother about a memory that we both should have, we rarely agree. And then I have my childhood best friend, Aaron Weakley. This happens all the time on this show. I think these fucking five ninjas jumped out, and that can't be possibly what happened when we left this bar.

I think that's true. And not just that, but you're communicating during these shared experiences. And you're communicating with this beautiful understanding of each other. This is actually a fascinating thing about. the brain is, in this context, we're creating this shared, I'm trying to get into your head and understand your goals and your understanding of the world, and you're trying to understand mine.

They've told that story together before. And so even the word ninja, like you guys, did that in a telling at some point.

Sure. Probably the morning after it happened.

Exactly. And so you guys are creating the story together, so it's going to match up.

We co-author all these memories.

Yeah.

So you do have prescriptions in this book. The goal of it being to make mindful and intentional choices to maximize the positive effect of memory on well-being and adaptive function. So I think people will want to know what kind of things can they do to make better choices, given that, as you say, most of everything we witness we're not going to remember. So if we're only going to remember 20%, how do we focus and become intentional upon that?

I think we need to allow ourselves time. Executive functions take effort and it takes time. And I think that's a big part of making these mindful choices, just giving ourselves the time to say, what is my goal here? What do I want to remember? And then there's another part of it, which is what are my goals in general?

Again, that makes me think a condiment in the experiential self versus the narrative self. It sounds like you're prioritizing the narrative self.

That's the self that calls the shots and that's the only self that lasts. This moment is already gone. It's memory.

Right. This has to be addressed, because it's probably the thing that's most present when you leave your house, which is, you go to a concert and everyone is filming the entire thing as if they're a videographer and as if they're going to watch this thing, which no one ever will watch this video. How are you obscuring your memory by doing that? How are you tainting it?

I love this because I'm noticing this. I was at a Descendants concert and it's like this older punk band, but there are all these young people there with their phones up. And I was like, people would be stage diving into these phones.

Swatting them out of hands.

Exactly. The interesting thing is, this relates to people's idea that if I document what happens, I will remember it.

Because of their spurious association with the memory, working like a video camera.

Exactly. And I think there's two things wrong with that. One is you're no longer actually, in the moment. You are thinking about recording. You're not actually experiencing this anymore.