Is Time Real? How Your Brain Perceives the Past with Dr. Lila Davachi

Ever wonder why time seems to fly or crawl? From ancient philosophers to modern neuroscientists, the nature of time has captivated human curiosity. This week on Science of Perception Box, we investigate the relationships among time, memory, and perception. Dr. Davachi shares the mechanisms of how the brain encodes and retrieves memories, including why emotions and feelings play a role in our perception of time. Lila Davachi is a prominent neuroscientist known for her research in the field of memory. She earned her PhD from Yale University in 1999 and currently holds a faculty position at Columbia University, where she leads the Davachi Memory Lab. Her work primarily focuses on understanding the processes of memory encoding, consolidation, and retrieval through behavioral and cognitive neuroscientific methods. Dr. Davachi has made significant contributions to the understanding of how memories are formed and maintained in the brain. She has published extensively in academic journals, with her research being highly cited within the scientific community. In addition to her research, she is actively involved in teaching and mentoring students in psychology and neuroscience. Dr. Heather Berlin is a neuroscientist, clinical psychologist and Professor of Psychiatry and Neuroscience at the Icahn School of Medicine at Mount Sinai in New York City. Dr. Christof Koch is Chief Scientist for the Tiny Blue Dot Foundation as well as the current Meritorious Investigator and Former President of the Allen Institute for Brain Science. Join us for new episodes every Thursday. Follow the show on YouTube, Spotify, Apple Podcasts, Amazon Music or wherever podcasts are found. Love the show? Write us a review on your podcast app or tell a friend about the show. Visit unlikelycollaborators.com for more information. Episode Chapters: (00:00) - Exploring Memory and Perception (04:19) - The Role of Emotions in Memory (13:32) - Therapeutic Approaches to Memory (19:25) - Time Perception and Memory (24:55) - Impact of the Pandemic on Brain Health (25:16) - Memory and Context During the Pandemic (27:34) - The Paradox of Time Perception (28:28) - Balancing Stability and Change for Mental Health (29:36) - Flow States and Time Perception (30:27) - Personal Experiences with Time Distortion (34:37) - The Construct of Time and Memory (37:34) - Perception Box Questions (43:35) - Closing Thoughts

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

  Time itself doesn't really exist in memory. And I would argue that time doesn't really exist after a few seconds, that it's really about where we're putting our attention, our internal mental context, how we're basically orchestrating our mind, what we're orchestrating our minds to think about.

• 0:18Speaker 01

  Hi, I'm Elizabeth Koch. We all live inside our own personal, private perception box, built by our genes and the physical, social, and cultural environment in which we were born and raised. In this podcast, we explore how although the walls of this mental box are always present, they can expand in states like awe, wonder, and curiosity, or contract in response to anxiety, fear, and anger. I'd like to introduce our esteemed hosts to incredible and distinguished minds. Dr. Heather Berlin, professor of psychiatry and neuroscience

• 1:02Speaker 01

  at the Icahn School of Medicine at Mount Sinai in New York City, and Dr. Christoph Koch, chief scientist for the Tiny Blue Dot Foundation and the current meritorious investigator and former president of the Allen Institute for Brain Science. Welcome to the Science of Perception Box.

• 1:24Heather Berlin?

  Hi, everybody. Welcome to Science of Perception Box. I'm your co-host, Dr. Heather Berlin.

• 1:30Speaker 03

  And I'm your co-host, Dr. Christoph Koch.

• 1:32Heather Berlin?

  Every week, we feature an aspect of the Science of Perception Box, highlighting the latest research together with our expert guests. This week, we're exploring the relationship between memory, time, and perception. I'm thrilled to welcome Dr. Leila Devachi, a leading neuroscientist at Columbia University whose groundbreaking work sheds light on the mysteries of the brain and its relationship with time. Dr. Devachi investigates how we encode and retrieve memories. Her work reveals that our perception of time is more fluid than we might think. In her research, she uncovers how the richness of our experiences, how varied and eventful they are, can stretch or compress our sense of time.

• 2:17Heather Berlin?

  Through fascinating MRI experiments, she shows that the brain's hippocampus plays a pivotal role in memory creation, while our internal experience can transform the way we perceive the external world. First, we want to share our own connection to memory. So Kristoff, what do you see is the relationship between perception and memory?

• 2:38Speaker 03

  Well, what do you expect from a guy who wears all yellow?

• 2:43Heather Berlin?

  Is this how you want to be remembered?

• 2:44Speaker 03

  I entertain my sunny disposition because I think, partially because what I choose to remember and whether those are positive or negative effects. So I think there's a strong relationship between the way you perceive the world and what you focus on and then what you remember. And that makes up your experience reality, your perception works.

• 3:04Heather Berlin?

  Well, there's two different issues there. I think one is, do you think that very strong, pronounced stimuli will help you remember something better? Or is it that you just want the memory to be associated with a very positive emotion?

• 3:17Speaker 03

  The latter primarily. I choose to, I think consciously choose to primarily remember good things about the world.

• 3:24Heather Berlin?

  You choose to remember good things about the world.

• 3:26Speaker 03

  That's the way how I do it. And I think we can all do that. We can choose to remember troubled things or insults or slides, or we can just choose to remember the positive things that we encounter.

• 3:36Heather Berlin?

  So basically, if we both encounter the same scene or other people encounter the same scene, what people remember from that scene can vary based on what their sort of perception is.

• 3:47Speaker 03

  What they focus on, yes.

• 3:48Heather Berlin?

  What they focus on. And so a person who's depressed might just pick up on all the sort of negative aspects. That's more salient to them versus somebody who has a happy disposition might remember.

• 3:57Speaker 03

  And if you do this consistently as a trade, I think it builds up your view of reality, your reality, because it's the only one you have.

• 4:08Heather Berlin?

  Well, I mean, we have an expert here who can help us with answering some of these questions. So Leila, welcome to the podcast.

• 4:16Speaker 00

  Thank you. It's great to be here. Well, it turns out that emotions do influence memory and negative and positive emotions do so in different ways, which is relevant to what you were just saying. Really negative experiences produce a very vivid memory, but that memory is fragmented and it doesn't include the context, what happened before, what happened after. But you can have a really sort of invasive, almost ruminative, negative memory. But positive experiences, on the other hand, tend to produce more flexible, integrated memories so that there's almost a bigger memory. There's more to remember

• 4:58Speaker 00

  and it's more flexible. And research has shown that when you're in an experience and you're positively motivated, let's say, searching for a reward, that you do activate the hippocampus more and that creates a more flexible memory representation. But if you're in that same environment, but you're avoiding a threat, you're trying to escape, you don't activate the hippocampus. In fact, you activate cortical structures and later on, you do remember that event, but you don't remember much about it. It's fragmented. So the central parts of a negative experience are remembered probably too well, but all of the important and interesting other parts of that memory are not there for negative experiences.

• 5:39Heather Berlin?

  That's really interesting. So it's the first time I've heard of this, that when it's a highly negative experience, it doesn't activate the hippocampus?

• 5:47Speaker 00

  That's been shown in human fMRI and in some rodent work, yes.

• 5:52Heather Berlin?

  But a positive experience would activate the hippocampus?

• 5:56Speaker 03

  So patient who doesn't have a hippocampus anymore because it's been surgically removed, they would not remember?

• 6:03Speaker 03

  Totally negative aversive events.

• 6:04Heather Berlin?

  They remember it from it, it, she's, you know, activates the cortex. So there's, there's memory areas in the cortex as well.

• 6:10Speaker 00

  So patient, this is really interesting. Patients with complete hippocampal damage who were amnesic still retain some aversive memories that they show in their behavior. So one of my favorite examples of this had to do with a patient HM who's very famous, who had no memory. If I walked, if I was him and I walked out the door, I would never even remember meeting you. But if you had shook my hand and you had a little sharp pin on the inside of your palm, I would recoil. And if I left the room, I would come back and not remember you, even with your yellow outfit, but I might not want to shake your hand anymore. That was an experiment that was shown. So they avoid engaging with the person who shocked them. So that tells you that there's something that remained about that negative experience.

• 6:55Speaker 03

  But it's unconscious.

• 6:57Speaker 00

  Without a hippocampus. Yeah. It's, it appears unconscious because they can, they can't really tell you much about the past.

• 7:02Heather Berlin?

  But it can't be that negative experiences. Sometimes they're, they're sort of hyper remembered, you know, like when, when people have PTSD and they can't stop thinking about these negative experiences.

• 7:13Speaker 00

  Yeah, no, no, no, completely. So the central core of the experience in that moment, when something really negative is happening, your pupil dilates, you're taking, actually time slows down, you're taking in a lot more information in that moment, at least that's the hypothesis. And that central information is well remembered, but nothing in the surround, not the contextual stuff, actually contrary to what people believe. They will claim after a negative experience that their memory is really, really good. And we call this flashbulb memories. But actually, when tested, their memory for what happened that day and the general context is no better than remembering what you had for lunch. It's not really special, but the central core information is really well remembered.

• 7:55Heather Berlin?

  Oh, that's interesting. And I, I do want to get into, in a little bit, I want to get into time perception during these experiences. That's something I'm actually really interested in and had done some research on time perception as well. So I want to dig in there. But first I just want to ask a general question of just like, what do you think the purpose of memory is?

• 8:12Speaker 00

  I'm so glad that you're asking that question because 10 years ago, no one was asking that question. People were asking, how does memory work with the assumption that memory is there to remember? And I don't think that's what memory is for. I think now, after dedicating 25 years of my life to studying memory, that memory is there to help us understand the world, to build knowledge. So, in other words, our memory systems are built to care about what's prioritized, what's important to learn from every day. And that's why probably the thing you can rely on the most about your memory is forgetting. Like, once you

• 8:53Speaker 00

  go to sleep, the memory system just doesn't consolidate and sort of literally trashes most of the day because it's not relevant to your survival. In other words, you've already learned so much about the world. So what tends to get consolidated during sleep, and this is when the memory system really gears up in action, is what is it going to keep around? What kinds of memories are going to undergo synaptic plasticity? And that's when you're increasing the communication between neurons so that you can remember that information later.

• 9:23Speaker 03

  This is doing specifically during slow wave sleep.

• 9:25Speaker 00

  This happens during slow wave sleep, and we actually have evidence that that might be tagged during awake resting states as well. That's what we've been looking at recently. So there's an interplay, I think, between the awake brain at rest and sleep. But so memory is, your memory system's trying to figure out, did you learn anything new today that is important to keep around? And it updates the cortex. It tells, so during sleep, it's teaching cortical neurons how to represent any kind of new, important information. So really, memory isn't for remembering, we think. It's really for gathering knowledge and updating our knowledge of the world.

• 10:04Heather Berlin?

  So would it make sense, though, and I think this leads into the time perception, but that the older you get, and the more buildup you've had of knowledge, so that maybe... The less you need to remember, in a way, right? Because I know, you know, my children, they're like seven and 10 now. They remember exquisite details of things that I just.

• 10:26Speaker 03

  They soak up everything.

• 10:27Heather Berlin?

  Everything, and they remember everything. And, you know, I forget most of things. But maybe that's adaptive. Maybe it's just because my brain, it doesn't need that information as much anymore.

• 10:38Speaker 00

  Absolutely. I think that instead of continuing to talk about aging as a deficit model, like memory in the lab, like little details aren't as well remembered. It's important socially to remember people's names, but people are generally bad at remembering people's names, no matter how old you are. But it's true, this could.

• 11:01Speaker 00

  This could explain what's typically thought of as a deficit, that as you age, your memories get worse. But what you are better at are knowing how the world works. And you can call that wisdom, you can call that making predictions. And there is research now showing that when older adults are facing the same memory question, or when they're encoding what's thought of as a novel item context experience in the lab, they're activating more of their cortex than their hippocampus. And younger adults or children are activating more of their hippocampus. And that's another way of saying they're gathering those details to be replayed during sleep. But older people, maybe, you know, if your brain were talking, might be saying, oh, yeah, I know what's gonna happen.

• 11:46Speaker 00

  No need to encode.

• 11:48Speaker 03

  How much is this process under voluntary control? So to what extent can I choose to remember, for instance, negative events? You know, some perceived insult that I may not want to recall, and primarily focus on positive memories? Or is this an illusion?

• 12:04Speaker 00

  Each of us have our own natural orientation, but that doesn't mean it can't be changed. Let's say, like, Kristoff, you're up here and you think of, you see the world through this, like, rosy glasses and you're picking in that moment. If you're able to attend to the positive aspects or reappraise in the moment, if someone is being. Rude to you in New York City, but you're thinking, oh, I probably had a bad day. It's not about me. Like, that kind of thinking may now, after many years, be where you are. And I may be down here. I may be really sensitive to perceived slights in my environment. And that means when I leave an experience, those memories are gonna pop up into my mind. And then I can choose to ruminate on them or not. I do believe that everyone can shift a little bit.

• 12:49Speaker 00

  Can I ever get to you? Maybe, if I work on it. But I don't think we're stuck. But I do think that there are gonna be individual differences. And knowing where you are is important and figuring out how to move that. But I also believe that it's much easier if you can change the memory before it's become a memory. In the moment, if your interpretation is there and the rosiness is already there, then that memory is more likely to be positive. It's much harder to change a memory once it's become consolidated. Once it's there as a memory, then you're more suppressing it. And that is only minimally effective. Suppression only works in the moment, but it doesn't seem to work in the long term.

• 13:32Heather Berlin?

  I'm thinking in terms of therapy, right? Therapy can be used, like I say, cognitive behavioral therapy, cognitive reframing, to move you up a bit, you know, move the needle up. But there is a limit in terms of, say, our genetic predisposition or the way our brains are wired. So there's certain, our boundaries might be set, but within a range. And that therapy can get you a little higher, you know? So we do have the ability to change over time. We're not sort of stuck in that. But isn't it true, though, each time you re-remember something, you can, you rewrite it, you know? And that part of maybe also what therapy can do is help you rewrite it in a more positive way, in a more beneficial way?

• 14:12Speaker 00

  Yeah, that's the big hope. Definitely, every time you reactivate a memory, it becomes labile and open to change.

• 14:22Speaker 00

  But so far, how much you can change that? It's really hard to make a memory more positive. Not that it's impossible, but you can make it slightly more neutral.

• 14:31Speaker 03

  So you're telling us I have this distinct memory of my first kiss when I was 15? And are you telling me that every time I recall that, I re-encode it?

• 14:42Speaker 00

  That is what we think. So when you activate a memory in the brain, when the neural ensemble or the engram is activated, it enters into a state of being moderately activated. And then that process can lead to either elements dropping out or elements coming in. Like if you're thinking about your 15-year-old self and your first kiss, and then you quickly moved the kiss you had last Saturday in your mind, and they're co-activated. Not that you would necessarily confuse them. That would be the extreme. You might confuse them, but they can become integrated in the brain.

• 15:18Speaker 03

  But that really means a memory is radically different from a computer memory, right?

• 15:22Speaker 00

  Absolutely.

• 15:24Speaker 03

  And it also means that my memories are amenable to being reinterpreted by myself or what I tell myself about who I was 40 years ago.

• 15:33Speaker 00

  And that's why therapy should work. So in the moment, activating the memory and then rethinking it, maybe perspective-taking, even just being calm. If your body is not aroused in a negative way when you're recalling a negative memory, that can help to disentangle. I call it the body memory, the fear memory, the heart rate increase, you know, the sweatiness. If you can feel calm, that's why propranolol works. Because if you have a beta blocker, which is a drug that's often used to... I'm not a medical doctor. Beta blockers are used for like stage fright. It's often given to patients with cardiac issues.

• 16:10Heather Berlin?

  It kind of calms down the nervous system, so you're, you know...

• 16:13Speaker 00

  Keeps your heart rate steady.

• 16:15Speaker 03

  When you're re-remembering your memory while you take that.

• 16:18Speaker 00

  While you're taking a beta blocker, what you're doing is... If you're retrieving a negative memory, that would normally cause a lot of heart rate increase. And now your heart's not increasing. The brain has an opportunity to disentangle or separate those two events. That's like the hope for for a lot of the use of propanolol. It hasn't been super successful yet, I will say, but there's still hope in trying to use.

• 16:40Heather Berlin?

  With phobias, like if you give people propanolol and then introduce them to like, let's say, a spider or something, you can actually unlearn a fear. In that even one trial, there's some studies that were done in the Netherlands on that.

• 16:53Speaker 03

  Now that you mention it, there is a spider behind you.

• 16:56Heather Berlin?

  Fortunately, that's not my fear. But if you mentioned a small plane, I might jump away. But you know, there is this idea with therapy as well. You bring up a sort of very negative emotion or memory in a neutral context with a safe person in a safe space, you can sort of re-encode it in a way that dissociates the negative feeling from the memory itself.

• 17:16Speaker 03

  But why does this all not work for PTSD?

• 17:20Speaker 00

  Well, it could just be that memories are so strong. I have my own experience with using propanolol to get rid of a fear of flying. So when I was on the job market for my very first job and I had, I was lucky enough to have multiple interviews. I would get on a plane to go to the interview. And my my interpretation is that I was preparing and anxious for the interview, preparing my job talk. What was I going to say to the professors I was meeting? And so my physiology was upregulated on the plane, you know? And then there I was on a plane that was like shaking. Maybe there was turbulence. So I think that my brain associated the plane context and the turbulence with my internal anxiety.

• 18:04Speaker 00

  So after the job market was done and I landed my job, yay, I found out that before all this, I never was afraid on planes. And now even getting on a plane to go to the beach, I was anxious. All of the turbulence bothered me. I became really afraid of flying. And I first tried like, you know, alcohol consumption. It didn't really work for me. I was still afraid.

• 18:26Heather Berlin?

  Alcohol consumption.

• 18:28Speaker 00

  It didn't work in the launch. And then I tried. Other medications that, you know, would knock me out and make me feel tired, but didn't get rid of my, um, my anxiety and fear of flying. So then I thought, I need to use science. And so I, my dad, who was a cardiologist, gave me a prescription for a propranolol. And I took beta blockers on one, two, three, or maybe six flights every time. Um, and frankly, you know, I was a little headachey. I didn't notice anything in the moment. I still had that fear, but after six or seven times taking it, I now I'm much more calm on flights. I feel like I've unlearned that is, my body has unlearned that, that association. So it is possible.

• 19:09Speaker 03

  Has your brain unlearned or has it learned this new association? This new positive association, flying doesn't have to be associated with the racing heart.

• 19:16Speaker 00

  That is a great question. And I don't, I think, you know, I would like to say the answer is usually in the middle. It's probably a little bit of both.

• 19:25Heather Berlin?

  But so I did want to bring in time, um, because this is something that fascinates me. So, you know, what is the relationship between time and memory and experience? And, you know, why is it that sort of time seems to expand? Actually, just, I, I recently testified as an expert witness in a court case.

• 19:48Heather Berlin?

  And it was about this woman. She died, um, unfortunately in a motorcycle accident. But she was conscious and aware during that time. And how even though it was just a few seconds, when you're in that moment of sheer terror and you, you know, impending, uh, you know, death, that it can feel way longer in those moments. Right? So subjectively, you know, how do you explain that? Where, what's the relationship between memory and experience and time?

• 20:19Speaker 00

  So what I know about that is that, and we've all maybe had an experience where there's something really arousing that demands our attention in the moment, that it can feel like the world is slowing down a little. So those experiences are happening at a slightly slower rate so that you can take in more information.

• 20:39Speaker 03

  Bullet time in the Matrix movie.

• 20:41Speaker 00

  Oh, bullet.

• 20:41Speaker 03

  When he's shooting his bullet goes incredibly slowly towards the

• 20:45Heather Berlin?

  You're aware that that's fiction, but we'll go on.

• 20:48Speaker 03

  Oh, thanks for finding that out.

• 20:52Heather Berlin?

  Just wanted to make sure.

• 20:53Speaker 03

  But it's a cinematic depiction of the experience that you mentioned.

• 20:56Heather Berlin?

  Yes, yes.

• 20:57Speaker 00

  So there is a lot of data suggesting that subjective measurements of time, your experience of time slows down in those really highly arousing moments. What we study in the lab is understanding whether that, how that translates into memories and how we remember time. And so that is what most of our research focuses on is memory for time. And in that case, what we're seeing is that time itself doesn't really exist in memory. And I would argue that time doesn't really exist after a few seconds, that it's really about where we're putting our attention, our internal mental context, what we're,

• 21:41Speaker 00

  how we're basically orchestrating our mind, what we're orchestrating our minds to think about.

• 21:45Heather Berlin?

  Wait, this is such an extreme. So you're saying time does not exist in our memory. So something that occurred in, let's say, real clock time, that was only a couple of seconds, could feel like an hour in your memory? Or something that lasted five hours could feel like a few minutes in your memory?

• 22:03Speaker 00

  Yeah, so we don't really ask how long it feels in objective time, because I think people don't even know how to do that. I mean, in general, if I ask you to retrieve a memory from your traveling here this morning,

• 22:18Speaker 00

  subjectively, what you get is not a continuous unfolding of the trip. You get these like slight movements, just little snapshots of where you were. And those snapshots are probably happening at the times you made a turn in the car. Right, so there are these moments that these experiences that we think tile are our experiences, these boundaries between events. So whenever the context changes a little, the brain is taking in those moments. But how much time is in between whether it was a really long trip on Broadway or just two blocks takes up the same space in our brains?

• 22:55Heather Berlin?

  From just a neural perspective, when there's change, this variation, there's dopamine that is released for novelty and that that might tag these moments as being important to remember.

• 23:05Speaker 00

  This is, yeah, absolutely. There's dopamine. There's also norepinephrine, which is related to our attentional systems. And the norepinephrine is allowing, we think, is telling us to take in where are you, what's your context? Like when your viewpoint changes in perception, the brain really quickly wants to know where it is. It really needs to have a sense of the context that it's in. And some people refer to that as the event model. What context am I in? What behaviors are required of me in this context? So that's what the brain is really good about. Within a few hundred milliseconds, knowing exactly if it needs to change, what active representations are available to you. Dopamine is also released,

• 23:48Speaker 00

  and dopamine has been correlated with your ability to now form a new memory of that experience. So it has a more long-term effect on the formation of the memory. And this is an area that is really kind of hot right now. And there's a lot of work that's being done to look at norepinephrine and dopamine at event boundaries.

• 24:07Speaker 03

  So tell me, what happened during lockdown, COVID, right, with time perception? When you talk about that, because most of us had this feeling, on the one end, it was way in the past, most of us don't even remember it anymore. On the other hand, this year collapsed to one or two points. So what happened then?

• 24:26Speaker 00

  So we all went through this similar experience, and it was very difficult for everyone, including me, but it was also very motivating for our research. Before the pandemic, we had already been studying event boundaries and event representations. And what's the relationship between kind of the ebb and flow of our daily lives and what's a memory? We had been studying that. The pandemic.

• 24:50Speaker 03

  You mean the beginning and the end of a memory?

• 24:52Speaker 00

  Yeah, what is a one episodic memory? Where does it start? Where does it end? And those are at these moments of change we've discovered. But at the pandemic, there was no beginning and middle and end. We were always in the same context, the same and definitely. So we were in the same apartment in the same house. Maybe you were lucky enough to have a backyard. You were in your backyard. We all were having groceries delivered to us. And so what I think has happened is that there's been a global reduction in overall brain health over the pandemic. So not having those moments of novelty where norepinephrine is released, your pupils dilate, the brain is taking in information. It's like a muscle, like really like the brain is like a muscle.

• 25:35Speaker 00

  If you're not using it in the proper way, you're going to see deterioration. And so if we're in that same context for months, let's say March 2020, until if you were lucky enough, September, you had some normalcy. But here in New York, really, it wasn't until a year later where there was people, you were able to go out. You had those experiences. At the end of the day, you could, you knew what had happened that day. You still had like a, like a little memory, a short term memory. But now trying to recall all those memories, they're all represented in the same context. And so they're completely interfering with each other. So our normal consolidation mechanisms, when you go to sleep, like I said, it are built to kind of rehearse.

• 26:20Speaker 00

  The brain rehearses the important events, but it also rehearses the context. When did it happen? Where did it happen? And those keys help you to unlock the memory later on. So again, if I ask you like, what did you have for lunch yesterday? Your brain is first going to go to where, where were you? What context was I in? And that's going to help you to think about, oh, where was the, where was the plate situated? Where did it come in? Was I at a restaurant? But if you had 100 meals in the same room.

• 26:49Speaker 00

  Knowing what room you're in would not be a key that would work for a specific memory. It would work to tell you generally where did we eat, but it wouldn't really give you any information about specifics. So we're all left with very few memories from the pandemic.

• 27:03Heather Berlin?

  That's so interesting. So it's really, memory is tagged to like sort of changes and you tag it to things in the environment and in your context, but if everything is remaining the same all the time, you don't really have anything to kind of latch on.

• 27:16Speaker 00

  Yeah, what do you latch on to?

• 27:17Speaker 03

  So it's not a facial record of what happened, but more of the salient events that are new and novel and interesting. And so that seems to explain then the paradox that seemingly time was very slow during the pandemic.

• 27:28Heather Berlin?

  Very slow.

• 27:29Speaker 03

  And in hindsight, I can't even say what actually what, nothing much happened.

• 27:33Speaker 00

  Right. The other side of that coin is when there's a lot happening in your day. Let's say you live a really busy life and you're constantly going from meeting to meeting, or you're on a vacation and you know, you're moving quickly through experiences. If you stop in that moment and someone asks you, how is your day going? How does time feel? You would report it going too fast, like time is going too fast. I, I kind of, almost like you don't like it, it's too much, like I feel frazzled. But that evening, in retrospect, you could actually have, you have all these memories you can pick up and recall in detail. And so your memory for time expands. Later on, if you, you know, in the moment you say, I have no time, time is short, time is short.

• 28:18Speaker 00

  Later on, as you're retrieving the memories, you're using those memories to infer time. That's the paradox. And then you say, oh, it was a really long day. I had a lot going on.

• 28:28Heather Berlin?

  So much.

• 28:28Speaker 03

  So what's the best for mental health?

• 28:31Speaker 00

  So this is what I was thinking about on the way. The, so the best is not one or the other. The best is again, something in the middle. And I actually think it's even more precision focused than that. I think what might be good for you might be different than what's good for me. And unfortunately, our world, especially the Western world is built up on, from the time kids are three years old, they're being told. When they need to do things and how long they need to be doing things. And so we're trying to push people into this box of 40 minute class, five minute break, 40 minute class, five minute break. And then in college and then in our jobs.

• 29:13Speaker 00

  And I think that at some point, what we should do for ourselves as adults, and then hopefully in the educational system, is figure out what

• 29:25Speaker 00

  what time scale works for us. In other words, we need to figure out how to interleave moments of stability. So we're forming these integrative memories and moments of change. So we need to have both in the day.

• 29:38Heather Berlin?

  Right. And not all one or all the other. And what about these flow states too? When you get into kind of a flow state and you-

• 29:44Speaker 03

  You mean when you are now, when you're focused on-

• 29:46Heather Berlin?

  Something really intensely and it feels like time flies by and, you know, where does that fit in?

• 29:54Speaker 00

  I can't say that I have been in a flow state ever in my life. I'm feeling, why don't you describe it more?

• 29:59Heather Berlin?

  We need to talk more about this. It's a feeling where you lose your sense of time and self and place.

• 30:04Speaker 03

  You're fully engaged with the world. Like when climb or on long distance running, you have to be hyper focused in one sense, but it's not about the ego. You experience time as Heather said, suddenly you sort of become two and realize, oh, here I am climbing or running or writing code. A lot of people have it when they've write code. Totally absorbs you, but you're very content, very happy.

• 30:27Heather Berlin?

  So I have an example of where my perception of time was completely distorted in my memory. And it happened when I was giving birth. I'll tell you my experience and maybe it's similar. No, not in the flow, but where time change-

• 30:42Speaker 00

  If only.

• 30:43Heather Berlin?

  If only. It was the last like moments, what it felt like the last moments when you had to like push and push and push. But eventually I had to have an emergency C-section because she couldn't come out. But this pushing part of it, like you would have to wait till the contractions come and then they would have you push and push. And to me, it felt like I tried doing that for like maybe 20 minutes or so, until they said, you know, it's just not going to work and we're going to have to go for the C-section. It turned out it was like three hours or something like that, which I still can't grasp my mind around.

• 31:14Speaker 03

  Oh, you experienced it as 20 minutes.

• 31:16Heather Berlin?

  Yeah, I thought I tried pushing a few times and then they were like, no, we gotta go to the C-section part. I had been in labor already for hours and hours and hours. So this was like at the tail end of it. Cause I was like, you gave up so quickly and took me to the C-section like, couldn't we try it harder? And they were like, you were there for three hours. I did not feel that at all. I don't remember any of that. I just remember about 20 minutes of pushing. But what was your experience? Was it different? Similar?

• 31:40Speaker 00

  My experience with my first child was I was in labor for almost 72 hours, mostly at home. And it wasn't constant. So I would be in active labor Monday to Thursday.

• 31:54Heather Berlin?

  Oh, my God.

• 31:55Speaker 00

  All night I was in active labor, about four or five minutes apart. And they tell you to go to the hospital around three or four. So I was waiting to cross that threshold, active labor all night. And then as soon as the sun would come up, it would slow down. It was still there, but it would slow down. So this went on for three days. And it felt forever. I had three turns of the sun. Really slow, never left the apartment, would slowly have tried all kinds of things. And it just felt like it was never gonna end. It felt very long and extended. And I like to contrast that with like the one minute between actually giving birth to my daughter and being able to see her face and holding her.

• 32:40Speaker 00

  And in that, that literally, I didn't, you know, felt like one or two minutes. I was looking up at the clock and I heard everyone in the, in the room. And you hear the gel and the weight being called out. And my husband went and picked her up and she came and looked at me. And so now I have this very rich memory of the sequence of events that occurred in that two-minute period. But my memory of the labor is just, I don't know, me floating around in a room. It was very small and very short, even though it was a much longer period of time. So I think that exemplifies some of the ideas that we're talking about.

• 33:11Heather Berlin?

  Yeah, I think really it does exemplify this, this, what I find fascinating. It really explains a lot for me as well as that. The more sort of monotonous the time is, it can be really long in real time, but your memory of it is much is contracted. The more either numerous changing events that occur within a period of time, or you know, emotionally salient events that occur can be short in the real time, but in retrospect, in your memory can be expanded.

• 33:41Speaker 00

  Exactly. That's the paradox. So in some ways, I think we like to prioritize the experience. If you're prioritizing your experience, then having that stability is nice. So think of, you know, a long day on the beach, or a Sunday where you decide you're just gonna stay home because you need to recoup. You need time in the moment to rest. But that's not gonna be a day that you remember later on, and that's okay. Like, sometimes we need to have those moments. But you don't wanna have too many of those because that is what depression feels like. Nothing changes. Your mental state is constantly in the same space. And even though you're walking around the world and things are changing,

• 34:24Speaker 00

  I think that depression is another way of thinking about it, is that you're being drawn to this local minima of your brain always working in a similar way.

• 34:32Speaker 03

  Depressed people have worse memory than non-depressed?

• 34:35Speaker 00

  They do. Yeah.

• 34:37Speaker 03

  What many philosophers and computational people emphasize these days, that time itself is a construct of your mind.

• 34:44Speaker 00

  Yeah.

• 34:45Speaker 03

  It doesn't really exist. There's not a natural mapping between external time and time in our head. It's a construct.

• 34:51Speaker 00

  Yeah. Imagine then the ultimate freedom where instead of waking up the way we wake up, most people wake up and think, oh, I gotta, gotta get to work, gotta have a meeting. What's your day look like? Your calendars. We have the spatial representation of our day. Imagine waking up and thinking, well, what do I wanna do today? What do I wanna accomplish? Imagine it's just one goal, but it takes four hours. But you allow yourself the space to get deep into that context, your mental context, to really let yourself sort out problems. No, but I feel like some of us have that freedom. We should.

• 35:26Speaker 03

  Once you're retired, if you ever retire.

• 35:28Speaker 00

  No, but I feel like that's the problem. I think that's a big problem with our field as scientists, like. Universities and institutes hire who they deem to be like the most, you know, productive, creative people, and then they put them on this crazy schedule that doesn't allow their brains to be deep and creative.

• 35:45Speaker 03

  Do retired people, do they have different memories? Do they, because they don't have this busy, oh my God, my first Zoom call is in 10 minutes?

• 35:54Speaker 00

  That's a good question. I don't know the answer to that, but I do tend to notice people who take up a new skill. They learn the piano or they learn painting. They allow themselves to get to, skill learning is really hard. It takes many hours and, you know, and, and I think they allow themselves to pick up skills that are quite impressive. And we think of as mostly children are good at picking up those skills. But I don't know the answer to how they feel about time and memory.

• 36:21Heather Berlin?

  I think there's something to be said with not over scheduling and, you know, allowing yourself to take the time you need to think deeply or get deep into something.

• 36:31Speaker 03

  Can we please finish this discussion, our Zoom call?

• 36:35Heather Berlin?

  Speaking of which, and the last thing, you know, I think time does exist in the physical world. Like there is, you know, we could, time is a dimension in physics, but our perception of time is a creation of our minds. And, and I've even looked at some of the research that I've.

• 36:46Speaker 03

  Block time, I would disagree with that. There's this block time universe that says everything is simultaneous, the block time.

• 36:53Heather Berlin?

  Okay, maybe there's no such thing as time, but our perception of time, our, our feeling of time is a creation of the brain. And one of, some of the research that I've done looks at when people have brain damage, a certain parts of the brain, the dorsolateral prefrontal cortex in particular, it really affects their perception of time. People have also orbital prefrontal cortex lesions. It affects their perception of time. So we know that it's, our perception is created in our brain and it can vary depending on the neurochemistry or, you know, the neuroanatomy. And we should just take it all with sort of a grain of salt, right? It's all, it's all a construct.

• 37:33Heather Berlin?

  So we end every episode asking a perception box question. And we don't know, I don't know what question Kristoff has chosen. He doesn't know what I have chosen. So we're gonna throw it out there and we all can answer the question or not, depending on how you feel. So do you have a question?

• 37:55Speaker 03

  Yes, I do.

• 37:57Heather Berlin?

  Okay, go for it.

• 37:58Speaker 03

  So what is the one memory that you keep on returning to? Is there sort of a dominant memory that you keep on returning to? And why would that be so?

• 38:11Heather Berlin?

  I have to think of this.

• 38:14Speaker 00

  Is there a dominant memory?

• 38:16Speaker 03

  Or something that sort of Spontinsky, Unbidden, keeps on coming back once a day?

• 38:20Heather Berlin?

  My mind is like a playground, right? And you get to choose where you go in it, right? When you're just sort of daydreaming. So I have less intrusive. I don't have so many intrusive thoughts or memories, but I, sometimes I'm like, it would be fun to remember this right now. Or I want to go live in this place for a moment. I had to go under general anesthesia just one time in my life for back surgery and I was very nervous about it. And I was told to just like, as you're getting wheeled into the OR, like before you go under, like try to kind of think of something, a memory, that brings you to sort of your happy place. Most people, it's like, I'm on a beach or whatever. But for me, it was the, so I did, you know, my PhD was at Oxford, at this, at Maudlin College, this beautiful college that was like magic to me. C.S. Lewis went there.

• 39:05Heather Berlin?

  But it had these, this like the cloisters. And whenever I'd walk in these cloisters, it just brought me such peace and comfort and just like I was connected to like history and whatever. And a beautiful like wisteria growing. And that is my happy place. So whenever I feel nervous or anxious, I will just go back. And in my mind, it's like so vivid. I can see every detail. I can see myself walking through these cloisters and the bells chiming in the background. It brings me such peace and joy. So that's a memory I go back to a lot on purpose.

• 39:37Speaker 00

  Yeah.

• 39:37Heather Berlin?

  Yeah.

• 39:38Speaker 00

  Yeah.

• 39:40Speaker 00

  I don't have an answer for you. I mean, I'm cued by what you said, and I can think I love nature and I would choose to be in nature because I feel more calm. But I'm constantly planning. And so I like I'm a list maker. So my brain is oriented towards the future.

• 39:58Speaker 03

  You're not.

• 39:59Speaker 00

  I can't recommend that for everyone.

• 40:00Heather Berlin?

  You're a memory researcher who's focused on the future.

• 40:03Speaker 00

  Right. So I am efficient. I'm reading a book by Miranda July, and there's a distinction between people who are Parkers versus drivers. Like, are you a Parker or a driver? And I love that distinction because I'm definitely a Parker. I'm a Parker even about driving. So, so unfortunately, I can't, I don't have, I mean, I do, my brain does tend to, I will admit, it does tend to reactivate situations that I wish would have gone differently. Like, I play a lot of counterfactual thinking from the past, but I'm often planning. What about you? Can you answer your own question?

• 40:41Speaker 03

  Yeah. Well, so I had two incredible meaningful experience. One, this near death experience that I think about every day. It happened almost, you know, four, nine years ago. I returned to it time after time because it was so meaningful. And then I had this sort of what people call a mystical experience again, and you come back to this, bidden or unbidden constantly. Both, by the way, have no time.

• 41:04Heather Berlin?

  So my question is, is there any action that you, or something you want to do, that, or an action you want to take that you just don't feel ready yet to do or to take?

• 41:15Speaker 03

  Yes, and it's what you alluded to, to go to this state where I wake up and the entire day, there's nothing planned. I'm not doing anything. I'm not giving a Zoom talk or, you know, writing a paper or book or whatever. But I'm also afraid of getting to that state. So what about you?

• 41:35Speaker 00

  Yeah. Well, I would think that you should be able to do that anytime. I think that that is a great goal for all of us. Again, but the planful mind.

• 41:43Speaker 03

  It sounds great.

• 41:43Speaker 00

  The planful mind.

• 41:45Speaker 03

  But then you actually have to do it for you. And that's more challenging. Oh, my God, I'm not going to do anything today. How does it make me feel? And look.

• 41:54Speaker 00

  Yeah. I think for me, I think a lot about wanting to be.

• 42:00Speaker 00

  In a state where I'm closer to nature and particularly animals, I have this dream to swim next to a whale. Like, so this is like this, you know, this, and I don't think that will ever happen in my lifetime. So I think that I think of myself as diving into the water. I have this image of complete freedom. I could swim with dolphins, it's true. I could probably make, but that would be in a, like a closed, I think in a big ocean.

• 42:26Speaker 03

  What about sleeping next to a big dog?

• 42:29Speaker 00

  I, I saw the equivalent. It's more about the water for me.

• 42:33Speaker 03

  Oh.

• 42:33Speaker 00

  So I do have this vision in my mind that's like, I love water and I feel completely free when I dive into the water. And so I would love, that's what I think about. I would love to be in that space one day where I jump off a boat and I'm swimming with a whale.

• 42:46Heather Berlin?

  I love that.

• 42:49Heather Berlin?

  I would like to be able to be more comfortable with letting go of control. And it's, you know, it's something I want to work towards where, because I always feel like I'm more comfortable when I'm in control of things. And I don't like surprises. I don't like not knowing and I, I just, it's, it's hard. It's, it's easy for me to let go in certain contexts, like if I'm painting or in a flow state or whatever, then I can let go. But like letting go in like the external world and scares me. So I want to work toward that.

• 43:22Speaker 00

  You're a parker too.

• 43:23Heather Berlin?

  Yeah, and I'm really good at palate parking.

• 43:25Speaker 00

  Yeah, exactly. So good that people clap.

• 43:28Heather Berlin?

  Yes. So yeah, I want to be able to figure out how to let go of control a little bit more. Well, I want to thank you, Leila, for a wonderful conversation and for joining us today. And if you'd like to learn more about your own perception box, spend some time this week answering the same perception box questions that we asked our guest. And check out other questions on our website at unlikelycollaborators.com. You can also subscribe to our YouTube channel and watch the show or listen wherever you get your podcasts. This has been Science of Perception Box, created by Unlikely collaborators in partnership with Podpeople. I'm Dr. Heather Berlin.

• 44:12Speaker 03

  And I'm Dr. Christoph Koch. Thank you very much.