Memory Explained: Why We Forget & How to Make It Sharper | Nikolay Kukushkin | FO571 Raj Shamani

Figuring Out with Raj Shamani

In this episode of Figuring Out, host Raj Shamani sits down with molecular memory scientist Nikolay Kukushkin to explore the biological and evolutionary foundations of how we remember, forget, and stay

Key takeaways

• Nikolay Kukushkin defines memory fundamentally as 'a change that outlasts its cause,' a biochemical process shared by all cells rather than just neurons in the brain.
• The primacy and recency effect demonstrates that human memory prioritizes beginnings and endings of sequences while naturally filtering out middle information, proving memory is constructive rather than photographic.

Main topics

• Memory formation and decay mechanisms
• Evolutionary psychology and dopamine-driven motivation

Notable quotes

Memory is a change that outlasts its cause.

Conclusion

The episode equips listeners with a scientifically grounded perspective on how memory and motivation shape daily

Transcript preview

Speaker 1 (0:00) Why do I remember certain things from 15 years ago, but I don't remember something from last week? Speaker 2 (0:06) We like to think that our memory is like a camera. It just takes a photo and stores it on the hard drive. That's really not how memory works. So I'm going to show you my credit card number. What do you remember? Speaker 1 (0:17) Last four digits. You're like most people, you probably remember the beginning, but almost nobody remembers the middle. This Speaker 2 (0:23) is called the primacy and recency effect. You remember beginnings because they're first, and you remember the endings because they are the most recent thing that you've read. And almost nobody cares about the middles. It already shows you that our memory, it remembers things that are relevant to you for specific reasons why your brain might pay attention to them. Speaker 1 (0:46) Nikolai Kukushkin. You're one of the top memory scientists. You study brains and minds. How can I learn to forget bad things easily? Speaker 2 (0:54) Most things in our brain fade over time. And most things that we hold on to, we recreate. So I think the number one advice is step out of the recreation and allow forgetting. Don't talk about it. If you're talking about it, you are recreating that memory. And the best that you can do is focus your attention somewhere else. That will naturally let that memory fade away. Tell me what's worse, no dopamine or a lot of dopamine? No dopamine at all is much worse. Craving things is what makes you excited. Lower dopamine person will tend to have less motivation. but also be less neurotic than a person with more dopamine. Speaker 1 (1:31) Evolution has designed me in a way that I'll always be unsatisfied. Speaker 2 (1:36) Evolution really doesn't care about how you feel about yourself. It cares about your survival. The ones who always seek more, they survive better than those who are satisfied with whatever they have, no matter what it is. The moment we get there... There'll be something else. That's just how we're wired. We need to accept that as a fact and just ride that ladder. Speaker 1 (1:58) Why can't I remember being a baby? And I ask so many people this question and they don't remember how they were as babies. Why? Speaker 1 (2:08) I have a small favor to ask you. I need you to subscribe to our channel. The more subscribers we have, the better and bigger guests we can bring and provide you more value through these conversations. And the full audio experience of this show is also available on Spotify, where you can follow us and listen to the new episodes as well. You are losing money without even realizing it. And one of the places where it happens the most is when you're shopping online. Your brain doesn't really know what anything is worth. It just picks the first number it sees and judges everything from there. Like when you see something marked for 2000 rupees and now selling for 500, that 500 in comparison to the 2000 feels like a steal. But that 2000 can be completely made up. A lot of times, some sellers push the price up right before the sale, then cut it so it looks like a big discount, when in reality, it's not. One way to catch this is to check what the price has been over time. There's a free extension called FlipShopAid that shows you that. You add it to your browser or get the app and shop like normal on your favorite e-commerce platforms. Then you can open any product and check its price history to see how much it has cost in the past, what it was priced at during previous sale and its lowest ever price. So you know right away if the discount is real. And if it's not the lowest yet, you can even set an alert and FlipShopA will notify you as soon as the price drops. So you end up buying things at the actual lowest price. That one habit alone saves you more money than you realize. To download FlipShopA, check the link in the description below. Speaker 1 (3:57) You're one of the top memory scientists. You study brains and minds. You study evolution. You have studied so many different species, brain and mind and how memories get formed. So you understand at this point, what are we thinking? How are we thinking? And how do we remember things much better than probably most of the people, right? Speaker 1 (4:21) Welcome on Figuring Out, Nikolai Kokushkin. Thank you. It's an honor to have you. If somebody is watching you for the first time and they have no clue what you do, they don't understand what memory scientist is. How would you explain them? What do you do? And why should they watch this podcast for next couple of hours? Speaker 2 (4:41) Well, I like to call myself a molecular philosopher, which sounds like a joke. But I say this because those are the two extremes of... Speaker 2 (4:53) brain, life on earth, reality that I'm interested in. I'm interested in the smallest material components of what makes us ourselves. And I'm interested in the biggest, most abstract, most philosophical things like memory, consciousness, motivation. What I'm most interested in is how one transitions into another. And that is what I study in the lab. I want to understand how the smallest most basic components of living matter molecules cells create Speaker 2 (5:30) those features of our mind that we consider almost magical, like memory and consciousness. Speaker 1 (5:37) Nice. And if somebody is watching this. Speaker 1 (5:41) podcast and they're going to finish it. What are they going to learn? Speaker 2 (5:45) Well, I think what they might learn is how we think. Speaker 2 (5:51) What motivates us to do the things that we do? Speaker 2 (5:55) what decides what memories we retain and what memories we discard. Speaker 2 (6:03) And I hope that it gives them a more peaceful way to live with themselves by recognizing which parts of our Speaker 1 (6:15) human nature we Speaker 2 (6:17) can't change and what we need to do to have a peaceful relationship with them. Speaker 1 (6:25) Tell me, can I force my brain to change? Speaker 2 (6:30) Well, anytime we're learning something, we're forcing our brain to change. That's what plasticity is. You're forcing new information into that brain. I think what you're asking is, can you force your brain to remember things better? Or Speaker 1 (6:44) can I force my brain to become a different person? Well, again, there Speaker 2 (6:50) is no such thing as repetition. Speaker 2 (6:54) If you're repeating something, you've already modified it. Speaker 1 (6:57) What do you mean by that? Any new experience. Speaker 2 (7:02) is written over a new brain. Anytime you've experienced something, you've changed something in your brain. People are worried about this or that changes my brain. They think of that as something bad, or in this case, it's something that you want. But there is no avoiding that. You are constantly changing. Every experience that you're encountering changes your brain. And not just your brain, your entire body changes. That's what my work shows, that actually the kind of mechanisms that our brain cells use to register events that are happening to them. Those same mechanisms work in every cell of the body. Kidney cells are registering kidney things. Gut cells are registering gut things. Brain cells are registering brain things. So there is no way that you can avoid changing who you are and what your body is. The question is, how do you route it where you want it to go? You can't stop this process. You can only trim it. Direct it, adjust it, work with it like with a garden. Speaker 1 (8:05) But, wait... You just said two things right now and they both are very contradictory in my brain. Speaker 1 (8:15) First is you said, every time, even if I'm remembering the same thing, it's new. It's not the same thing. It's not repetition. There's nothing like repetition. Is that what you're saying? Speaker 2 (8:27) You are repeating it. But it's not the exact same thing as what happened before. This is the phrase by, I believe, Russian physiologist Vygotsky. Repetition without repetition. When you're learning a skill, every time you're repeating it, you think that you're repeating it. By the time you've repeated it, your body has already... changed, your muscles have changed, your brain has changed, and you're adding on to that change, you're solidifying that change, you're directing that change, you're restricting possible movements. When you're learning a skill, for example, the first thing you need to do is block out the movements that don't lead you to that productive action that you are trying to achieve. First, you block that out, you restrict the paths that lead to that action, and then you optimize what are the movements that might lead to it. But every time you're practicing that skill, your brain adds a little layer of learning. Speaker 1 (9:24) There's just no avoiding that. If I meet you today and we hug each other, we shake hands. And then we do this one week later, and then three weeks later, and then one month later. Every time that handshake is different? Speaker 2 (9:41) Of course. Well, the next time you will remember me, we'll be better friends. And so that will probably cause a different emotion than what happens the first time we meet. And then the third time, well, maybe you'll be bored of me. And that will be another emotion yet. And then maybe by the fourth time, maybe we won't see each other for a while. And then it'll be like meeting an old friend. Every experience is different, even though it doesn't seem like this to us. It's very hard to believe that you are a different person because we inhabit this body. We look from these same eyes into the mirror. We see this object with the face, with the hair, and we think that it's static. We think that it's the same thing as it was yesterday. But that's just not true. We're different every day and every minute and every second. Speaker 1 (10:23) When did you find this? That there's nothing like repetition? Because... As someone who loves practicing a certain craft, but actually becoming better, my whole brain, everything in my practice just goes like, okay, if I repeat something for n number of times, I'm going to get better. So I'm repeating the way I talk, the way I'm breathing, the way I do a certain exercise, the way I'm actually writing, everything I'm repeating. And that's the concept that repetition makes you better. And you are saying there's nothing like repetition because... You're a different person. So when did you find this out? It makes sense though, whatever you're saying. Speaker 2 (11:05) Don't get me wrong. I'm not saying that there's no point repeating anything. No. Repeating something is the surest way to get better at something, to learn something. That's the pattern that tells our brain that something is important. Really, our brains memorize important things and repeated things. And if you want to memorize something that your brain doesn't naturally think is important... The way to convince it that it's important is to repeat. All I'm saying is that in order for this repetition to work... The first event, the first repeat, has to modify something in your brain, in your body, that has to carry over to the second repeat. And that second repeat has to land on that. Somehow your neurons, your body, your cells need to know that it's not just one more. It's not just an isolated event, but it's, again, it's something that's layered on top of a previous repeat. And that's been my longstanding interest in how does a neuron know what is again? What is retained that is not the memory itself, but something else that is retained within that cell because we see it in single cells in a petri dish. What is it that is retained in that cell that then plays out when the second event lands to cause something that the first event didn't? How do we get from one plus one plus one plus one? And that doesn't equal four, but it equals more than four. That's the real question about this again versus not again, repetition versus not repetition. Explain Speaker 1 (12:42) me how and why. Speaker 2 (12:44) Well, for example, in one of our studies, we showed that there are two molecules inside of a neuron that cancel each other out, that interplay with one another, and you activate those molecules to a different extent. depending on the strength of the stimulus. And depending on how much you activate them, their activities remain in the cell for a long time or a short time, and one of them wins over or another one wins over. It's a fine dance between these two molecules. And what it means in practice is that if you stimulate that neuron in an escalating pattern, if the repeats become stronger every time, Then those molecules play out in such a way that the activating one will eventually win over and the memory will form. If you do the opposite, if the repeats wane, if the first one is the strongest and then it goes weaker, weaker, weaker, weaker, then the deactivating one ends up winning and no memory is formed. And that makes total sense because anything in nature that escalates, well, it's more important than anything that wanes. Speaker 1 (13:54) And Speaker 2 (13:55) you have to prioritize. You can't remember everything. You have to choose what to remember. And that's what really memory is about. It's not just storing, piling information into your brain. It's prioritizing. It's recognizing patterns. It's selecting patterns that are relevant. And escalation is a more relevant pattern than dissipation or waning. So that's an example. You have this dance of these two molecules, and that is what retains the trace of repetition and determines what kind of pattern. you will remember or not remember. Speaker 1 (14:28) Interesting. So how can I actually train my brain and every cell to remember? the good things, the positive habits, the things which are difficult to do and not the bad things. Because my body automatically remembers the bad thing, even though if I've done one time, it just remembers it somehow. But the good thing, it doesn't. Well, Speaker 2 (14:51) first of all, I bet that in your case and in my case, there's plenty of bad things that we simply don't remember about. And that's why it seems that they never happened. But what I always find is that bad memories actually... fade a lot faster than good memories. That's what keeps me sane when I'm traveling somewhere and I have all these stressful experiences and that might be stressful in the moment, but I know that eventually that will fade and what I will remember is the good things. That gives me comfort. So how do you make that happen artificially? Well, I think that there is no trick to remember good things or bad things. The trick is to to perceive the right things to to filter through your brain what you want to remember how you want to remember it and in the frame that you want to remember it i don't think we talk enough about mental hygiene We understand that there are certain healthy habits that we have to apply to our body. You don't need to wash your hands. You don't eat too much junk food. You have to eat plenty of fiber, drink water. We're all familiar with these ideas that mainstream, it's indisputable. Speaker 1 (16:04) But Speaker 2 (16:04) there's a lot less discussion of doing the same thing with your mind. We're consuming a lot of mental junk food. It seems that it just disappears and doesn't do anything and you know one day it's here and another day it's gone. But it's not. Everything that we're consuming mentally or physically leaves a trace. So in order to ensure that long term your memories are healthy and happy and point you to the right direction you have to Tend to your brain like a garden. I'm going to keep repeating that line because that's really how I think. We like to think that everything in our memory just happens in one moment. That you can dump some memory into it and it gets stored in there and that's what it is. But memory is a constructive process. It evolves, it changes depending on who you are and how you think. So memory is constructive. It's what you... project onto it. There are famous studies into false memories, for example, maybe you've heard about the 9-11 study. This was the one case where you could track a memory across large populations of people because everybody had experienced, everybody who was alive at that point experienced 9-11. And the old form was called a flashbulb memory, something that you can vividly recall and you're 100 % certain in what it looks like where you were. I have that image. So researchers... Speaker 2 (17:36) Talk to people a day after the event and a week, a month and about a year afterwards. And they interviewed them about that same memory and they tracked how much it changed and how much confidence people have in that memory. And what turned out is that the confidence stays exactly the same for this flashbulb memory. You ask a person and they say, I'm sure, yeah, this is exactly what happened. It's right in front of my eyes. But the. details that they recall from that memory, a third of them disappears by a month and even more by a year. I'm not exactly sure of the exact numbers, but that's the scale of it. So what does that mean? It means that there's a disconnect between what we perceive to be the accuracy of a memory and what it actually is. Anytime you are recalling a memory, you are rewriting that memory and it becomes a little bit your imagination. And every time you keep doing that, this imagination is introduced into the memory more and more and more. And you don't feel that. You don't know that something has changed about your memory. So, think about that. And think about everything else that you remember about your past. Your entire autobiography. We have no idea how much of this actually is true. It's a confabulation in a large part. It's a story that we keep telling ourselves. Speaker 1 (18:58) So you're telling that half of the things or more than half of the things that I remember about myself or the past version of myself or a certain experience that I've gone through, it's all my imagination. It never happened. It Speaker 2 (19:11) might be. If you are like most people, then it probably is. And I think it's fascinating that we as a society now have ways of checking. You know, we have writing, we have photography. We have the internet. But go back a few thousand years ago, and that just wasn't a reality. There wasn't a way to check whether or not your memory is true or not. And so history moved at a much faster pace. Without writing... everything changes within a generation. All the shared memories basically are replaced with imagination. So it's very difficult to go back in time, even today to societies, to cultures that don't have writing and think about the past. Speaker 1 (20:02) Like, are there certain things that people make up more versus certain things that people don't make up more? Like there are probably certain experiences where there's more accuracy in remembering. And there are certain events where majority of people are just imagining things up. Speaker 2 (20:18) Well, so the same 9-11 study also tracked everyday memories, just your regular memory of what happened today. And what they found was that actually the rate at which this flashbulb memory, the 9-11 salient memory, I imagine it just as it was, the rate at which it decayed was... exactly the same as the rate at which everyday memories decayed. It's actually really remarkable how closely they tracked each other. What was different is the impression that people have about the accuracy of the memory. So I think it is likely that most of our memory dissipates at a more or less even pace. And what is different than our imagination is how much accuracy how much confidence we attribute to Speaker 1 (21:09) this memory or that memory. Speaker 2 (21:11) That being said, for example, there is well-known literature on the fact that you forget things faster. If the task is complete. If you decide for yourself that I'm done with this, I no longer need to remember this, even if you really want to remember it. But if your brain decides that the task is over, the memory is gone. I experience this all the time with my students. I think that I've trained myself to remember student names fairly well. I usually have three sections of 25 students, so 75 people per semester. pretty sizable memory task to remember. But I know that in two, three classes, all of their faces will become salient. I will attribute all the names. Embarrassingly enough, it is a little bit slower for students from other cultures, which I think everybody experiences, but it will happen. But then, when I'm done with the semester, poof, it's gone. And I want to remember all my students. I want to remember their names when I see them in the street, but it's almost like a wall that I'm hitting. What's especially interesting to me that's unrelated, that when I see a student later in the street and I think, oh, I lost the name. I don't remember it. I will think about it and I'll think about it and I'll think about it and then it will pop back in. What I'm most interested in, and I really don't know the answer to this, is what is happening in my neurons? When I'm doing this. Speaker 2 (22:45) That later, sometimes an hour after that, will cause them to pop and produce that memory. That's what I'm really deeply interested Speaker 1 (22:53) in. Speaker 2 (22:53) And Speaker 1 (22:54) you Speaker 2 (22:54) don't have an answer for that? I don't have an answer. My guess is that there are some biochemistry, some genes are getting turned on, some proteins are getting produced. What's fascinating to me is that it takes time. It doesn't happen instantly. It doesn't happen in that moment when I'm straining. It's not like something breaks through a wall in that moment. It's some slow process that requires time to fully unfold. And then it just delivers that memory to me as if it was always there. That is just magical to me. And I wish that I understood exactly what was going on. Speaker 1 (23:26) Is there a trick to remember everyone's name when you meet them? A lot of people... use Speaker 2 (23:32) a technique called memory palace. All the people who competitively memorize something, there are real competitors out there, people who do this for a living. Pretty much all of them use this technique called memory palace. What is that? It was actually invented by ancient Greeks, ancient Greek philosophers who put a lot of emphasis onto memorizing. It's interesting. We think of the internet and AI as things that we outsource our mind to and that makes us dumber. They thought of writing. the same way. If you're writing things down, you're not a proper Greek philosopher, you gotta be memorizing things. So they put a lot of value onto it. So what it is, is basically creating a visual scaffold for your memory. You have to cultivate it, you have to work on it for a while, you have to imagine this elaborate space, like a palace or castle or just a big room or something with closets and the car and cupboards and corners and objects and then when you're trying to remember something you are mentally placing that into a particular shelf or cupboard or onto an object or somehow visually placing that in that memory palace. And that's just associating this new information with something that you already have in your brain that helps you tie it to your existing mental model. Because that's really how we add new information to the brain. We like to think that memory is just this hard drive to which we can dump anything and it wouldn't matter. That's how we deal with computers. A computer doesn't care what kind of file you place on the hard drive. But we need to think about our own memory not so much as a hard drive, as much as modifying the thinking paths, modifying the thinking machine. That's what our memory is. And so it is a lot more efficient if you're modifying something that's already there. rather than just trying to add something that's completely irrelevant to anything else in your life. So if you can find some association, it doesn't need to be anything smart, just some visual or auditory association between a name, something else that it reminds you of, put that into a corner of that memory palace, and then remember to get back to it whenever you see that person again. That will improve your memory. Speaker 1 (25:56) That I'm just thinking about the things that I do. Every time I meet a new person, especially let's say in my team, and there are like hundreds of people, and it's very difficult to remember everyone's name because you don't meet them on an everyday basis. Speaker 1 (26:12) Whoever I meet, if I know their hometown, then I immediately associate that person from that particular town and I remember the name. Speaker 2 (26:21) That's exactly right. You're constructing a tiny memory palace by simply doing that. You know, it doesn't have to be a physical space. I have a big memory palace for biology. You know, I already have a lot of base for that. So it's easy for me to read a paper and just attach it to what's already there. I can't do that with music. A musician would hear a melody and would parse it in ways that would make sense to them and attach it to their model, to their memory palace. By thinking through those details that you associate with a name, you are growing that name deeper. into your brain. And that makes sense that it would be easier to recall. Speaker 1 (26:59) Interesting. It makes sense. But there are some people who remember bad memories and they can't move away or like just move on from those bad memories. Why some people remember bad memories more than good memories? Is there a reason? Speaker 2 (27:17) Well, our ability to memorize is separate from our ability to forget. And both of them... can be at different levels. And the temptation is to assume that the important one is the remembering and the less important one is the forgetting, that we want to remember as much as possible and we don't want to forget anything. But your example illustrates that forgetting is just as important, is just as much a part of this process of learning. An even more vivid example is people with photographic memory, with extreme memory. It's very rare. But there are cases described in literature of people who have this astonishing memory that is impossible to even imagine for us normal people. There's one famous one in Soviet science, Stanislav Szereshevsky, or Mr. S, as he's known in English. Mr. S had the kind of memory that you could read him a foreign language. Divine Comedy in Italian. He didn't speak Italian, but you would read him Divine Comedy in Italian, unprompted. You don't tell him to do anything. Years later, he would recite entire pages of that. Or mathematical equations, just numbers, pages of numbers. He would be able to recall that from memory. And a lot of us might think, great, that's what I want. That's amazing. I will never forget anything. But it wasn't a gift. It was a disability. because his life was basically unlivable. Everything that happened to him ignited this explosion of associations. He couldn't focus on anything because everything caused anything. Anything that he tasted, tasted like everything that he'd ever tasted. It all came into these different, every kind of food that he's ever put in his mouth. He couldn't understand. Anything metaphorical. Because a metaphor is an abstraction. You need to remove yourself from specifics. You need to see a big picture. You need to see a generalization. He couldn't do that. He remembered everything specific, but he couldn't abstract himself because that requires forgetting. He had trouble remembering people because he remembered how their face looked from this side, how their face looked from this side. But he couldn't compile that into this generalized image of this is that person. He remembered each side of their face separately and it was very hard for him to compress that into a knowledge of an individual person. So that kind of life where you remember everything, it is far from pleasant. We need to forget as much as we need to remember. Speaker 2 (30:20) to maintain sanity so that we forget the bad memories, like you said, but also so that we could think, so that we could process reality in real time, so that we could see patterns in it rather than just specifics. Speaker 1 (30:32) How can I learn to forget bad things easily? Well... Speaker 2 (30:38) Most things in our brain fade over time. And most things that we hold on to, we recreate. So I think the number one advice is step out of the recreation and allow the forgetting to take its course. You know, even addiction. Addiction is a form of memory. Whether it's addiction to a drug or addiction to social media. It's a memory that we decided is bad for us. Really, there is no line that separates addiction from non-addiction except a doctor says that's really a problem for you and you should not do it. So how do we get rid of it? Well, social media is probably the easier example. But if you step away from it... Yeah, it's going to be hard for a few days, but the dopamine system that draws you into it, it gets recalibrated and on the scale of days, a couple of weeks. And well, maybe you won't return exactly to the baseline where you were without knowing what social media were, but you will get most of the way there and your brain will recalibrate and you will be able to perceive the same social media freshly and see them in a different light. So I think. That applies to most memories. You need to find a way. Speaker 2 (32:06) In which you yourself don't bring that back. Refocus on something else. Don't talk about it. If you're talking about it, you are recreating that memory in your own mind. You think that you're talking it through. And in some cases, that's important. If the memory is unresolved, there's something about it that still occupies your mind. If that's the case, if it tries to resolve itself, find the... solution, and you can't quite find it, then it will be there until you find the solution, then you do want to talk through it. But if it's purely something that was a bad experience that you don't want to hold on to, then talking about it won't help. And the best that you can do is focus your attention somewhere else, occupy your brain with a different task, find something that's totally different that will make you forget about it, go and travel for a couple of weeks. And that will naturally let that memory fade away. So I think the thing to remember is that everything is always in flux. It's not just sitting there in a hard drive. It's more like a feed in social media. Things that you don't interact with, they will eventually drop to the bottom of that feed and will get forgotten. And it's the things that keep getting comments added and keep getting likes that will stay on top of it. And they can stay there forever if you keep doing that. But Speaker 1 (33:24) don't you think a lot of people say, and a lot of experts, they say that... Talk about your bad experiences. Talk about what you're thinking. If you won't talk about it, if you won't relive it, you won't be able to heal it. You should talk everything that you're going through. Yeah. Well, if you do that more often, according to your theory, then it's bad because you're technically reliving it. And every time you relive it, you recreate and you add a little bit of your imagination and story to it. So you're making it worse. Speaker 2 (33:53) Because Speaker 1 (33:54) every time you're reliving the same emotion. Speaker 2 (33:56) I think that we need to distinguish between reliving an emotion and talking through the unresolved. Because I think that, at least for me, a lot of my negative emotions, they come from this repeated engagement with something that I can't change. Something that is on my mind because there's nothing that I can do about it. And if I talk about it... It only escalates that emotion. And that's what gets written into my brain. And that's what keeps me coming back to it. And because there is nothing in the end of that loop, I don't think that talking more about it helps. I watch people talk about politics, which I prefer to avoid. And a lot of times I see that people dig themselves into a hole. They know that they can't change anything, but they still... try to do that with their mind. And I think there's value in stepping