What are your dreams really telling you? Renowned sleep researcher Dr. Robert Stickgold joins Dr. Stieg to unravel the mysteries of dreaming. From the bizarre to the brilliant, dreams are a window into how the brain processes memory, emotion, and problem-solving. Learn why your brain needs to dream, how dreams shape your waking life, and what science says about interpreting them. Whether you’re a vivid dreamer or rarely remember a thing, this episode will change the way you think about what your brain is doing when you go to sleep at night.
Phil Stieg: From ancient oracles to modern therapy couches, dreams have fascinated and guided us, revealing the workings of our deepest thoughts and emotions. Far from meaningless nighttime noise, dreams have important functions. They help us solve problems, heal from trauma, and integrate our memories. Today’s guest, Dr. Robert Stickgold, is a Professor of psychiatry at Beth Israel Deaconess Medical Center and Harvard Medical School and has pioneered groundbreaking research on sleep and dreaming. He is the co-author of the book “When Brains Dream.” Today, we’ll learn from him the importance of dreams and how dreams shape our waking minds. Bob, thank you for being with us.
Robert Stickgold: Phil, it’s a delight.
Phil Stieg: So I’m reading your book, I had the fundamental question, why should we study dreaming?
Robert Stickgold: Wow, I don’t think anyone has asked me that question before. You’re challenging my fundamental life purpose. We should study dreams because, first of all, they’re fascinating, and we always want to know more about ourselves. And second, because dreams are an insight into how the brain processes the information that it takes in during our daily life and to understand why it’s doing it, how it’s doing it, and how that processing becomes visible to us in our dreams, tells us something both about ourselves and how the brain works.
Phil Stieg: Can you talk a little bit about the importance of sleep in our lives?
Robert Stickgold: Yes, so sleep is often thought of as literally just a time when your brain shuts off and isn’t doing anything. Nothing could be further from the truth. The entire time you’re asleep, your brain is working. Parts of the night, the brain is more active than it is during normal wake.
What is it doing? Well, amongst other things, and it’s doing things for the immune system, doing things for the endocrine system. Just to digress for a second, if you If you sleep-deprived someone the night after you give them an influenza vaccine, they only end up producing half as much antibody to the flu. If you have someone on four hours of sleep for a week, they start to look prediabetic. I don’t want to say that sleep is only for the brain and only for memory. That’s just my focus.
But the brain is processing memories all night long, and it does it in a half dozen different ways. It takes some memories and just strengthens them. It takes other memories, holds on to the core of the memory, and forgets all the details. It takes more complicated memories and discovers patterns in in the data and rules in our life. You can really say that when people wake up in the morning, they understand the world better than they did when they went to bed the night before. That’s probably the main evolutionary reason that we dream. That ability to understand the world better, my God, that’s the greatest survival advantage you can gain.
Phil Stieg: Why do we dream?
Robert Stickgold: We dream to get better understanding of our possible futures that allow us, when we’re awake, to better plan our lives.
Phil Stieg: Obviously, dreaming occurs during sleep. So walk us through the sleep cycle and the relevance that each phase of the sleep cycle has with regard to dreaming.
Robert Stickgold: So it turns out that sleep is not a uniform state. You don’t fall asleep, stay asleep, and then wake up. Your brain is actually going through a highly orchestrated series of brain states, almost like movements in a symphony where you go into deeper and deeper stages of what’s called non-REM sleep, where rem is rapid eye movement sleep. It’s not named after the band as some people thought it was. So rem sleep is the time that comes about every 90 minutes through the night, getting stronger and stronger with each 90 minutes cycle. It’s the period where you have these rapid eye movements. If you watch someone sleeping, especially a baby, because babies will do it when they first fall asleep, you can tell that their eyes are zipping back and forth in their sockets. Physiology and chemistry are changing. Serotonin release is being shut off. Noradrenaline release is being shut off. A lot of the neuromodulator that really control the program that’s running in our brain, those are shifting dramatically. If you look at dreaming across these stages, you see a progression. And earlier in the night and in the lighter stages of non-rapid eye movement sleep, the dreams tend to be more realistic. They tend to relate more clearly to recent events in your life. When you get to rem, they become completely bizarre, hyper emotional, hyper visual, and it’s hard to figure out exactly what they mean.
It tends not to be a recent event, but either much older events or not actually events. In non-rapid eye movement sleep, you might have a dream about flying saucers. When you wake up and you say, Oh, just had a dream about that pizza I had last night. It was a pepperoni pizza, and I really liked it. I think that’s what that flying saucer was. If you have the same type of dream in rapid eye movement sleep, what you’ll find when you ask the person, Well, where does that come from? They’d say, Oh, I love pizza. It’s a more generic statement than specific event, as if the brain is going and looking at networks of associated memories rather than a specific memories from, say, the day before.
Phil Stieg: I really want to recommend your book to everybody because I think that it does almost an encyclopedic review of the history of the analysis of dreaming. But you do it in simple prose so that a novice like me can actually understand it. However, it also centers around your theory called Next Up. Could you explain what that acronym means and briefly summarize your theory on dreaming?
Robert Stickgold: Sure. Next up stands for Network Exploration to Understand Possibilities. It basically says that what the dreaming brain is doing is going through these files of old weakly-related memories, this is the network exploration, and then it’s acting them out, if you will, in our minds to let us determine or let the brain determine whether these might be useful. It doesn’t make declarative decisions. It doesn’t say, Bob, what you’re doing in your argument with your wife is like throwing fruit around in a grocery store. It’s more gentle. It’s more like a therapist, and it says, What about that? Is it worth thinking about that? So it’s about possibilities, not answers.
Phil Stieg: You and I are talking, so I’m totally focused on that conversation. But there’s other things going on around us in the world while we’re having a conversation that your brain is actually absorbing. How does that play out in dreams?
Robert Stickgold: Dreaming is a time when the brain is exquisitely tuned for finding those surrounding stories, finding the things related to what my focus is. I’m focused on this argument with my wife. (Now, I wish I had taken a different example.) But it’s also looking at what’s in the surrounding, what’s in the environment, what’s the context in which this conflict has risen? That not only helps me as an individual the next day deal with this ongoing conflict, but it also helps build the structure within my memory system that better encompasses the reality of the conflict.
Phil Stieg: The thing I was completely unaware of and most fascinated by is how dreams can possibly affect our lives and you can solve a problem. The expression you said, “I’m going to sleep on it.” The benzene ring in organic chemistry or Paul McCartney with the song Yesterday, were the result of dreams, correct?
Robert Stickgold: Yes, they were. So There are many, many anecdotal events where we’ve got three Nobel Prizes where the Nobel Laureates say, Oh, I dreamt of this. That’s how I figured out this solution. Or songwriters or writers of books. But these are the exception. These are really the exception. Maybe that proved the rule.
But in all of our brains, all of our brains are being that creative. We don’t always remember the dreams, and according to our theory, you don’t need to remember them because when the brain plays out some scenario and determines that it’s actually a useful older memory that it’s discovered, it makes the connection between that older memory and your current concern right there in the moment.
You don’t have to remember the dream later to make that connection. That remembering the dream really is a freebie. It has to happen in consciousness because consciousness turns out to be the only place where we can imagine, where we can project and imagine future scenarios. So it’s allowing you to have a little picture into your future and that’s incredibly valuable as a survival tactic originally, and then for all the creativity and problem solving that we do in our lives today.
Phil Stieg: I’ve had friends that want to tell me about their dreams, and I find them boring, but they find them incredibly interesting. Is the brain doing something to a dream to make the individual that has it feel that it is some earth-shattering or important event?
Robert Stickgold: It’s funny. You should say that I tell people I have two rules for them about dreaming. Number one, don’t tell other people your dreams. Trust me, they don’t want to hear them. The second one happens to be, don’t make any major life decisions based on a dream.
But going back to the first one, dreams for thousands of years have obsessed – and that’s really the right word – have obsessed people. The question is, why would that be? And what we believe is that in evolution, the brain now is looking at older weak associations, trying to decide whether they’re useful. And the brain wants to loosen up the standards that it uses. I mean, if it’s going to be serious and competent and all that, it’s going to say this is a ridiculous connection. It’s going to be that because we didn’t think of it when we were awake. So the brain is saying, Okay, back off. I want the brain to be more like my mother. If I told my mother I discovered something at work, she would say, Oh, Bobby, that’s so wonderful. That’s incredible, even though she had no idea what it meant. I don’t want it to be like my father who would say, Well, that’s kind of obvious and stupid, even though he didn’t understand it either.
We want a brain that’s more lenient. We think what the brain has done, especially during rem sleep, is stop the release of serotonin. Stopping that release loosens these constraints on what we consider valuable. The only other case where I see people acting so foolishly was back in the ’60s, where they would tell me their LSD discoveries. You know they said, “I was on acid, and I suddenly realized that when you flush the toilet, everything goes down”. Then there’s this pause, and they say, No, but it meant more. It explained everything. There’s something about the physiology of the brain when you’re taking this serotonin antagonist that makes the mind and the brain assign more significance to things. When we think they’re significant, we want to share them with people… Don’t.
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According to Dr. Stickgold, sleep and dreaming is an important process by which humans sort out which memories are important to keep and which we can afford forget.
But what about other animals, who, while they’re asleep, also have important things to remember – like coming up to breathe?…
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Since the 1960’s scientists had theorized that dolphins must have evolved a way to keep swimming while they catch a few ZZZs. How else could they return to the surface to breathe while dozing? But in 1999 researchers in Humboldt, California, determined that dolphins actually allow one hemisphere of their brain to go to sleep while the other stays awake to keep swimming and breathing. The clue was in the dolphin’s eyes. Mammals’ eyes are connected to the opposite hemisphere of their brains, so when the dolphin’s right hemisphere went to sleep, its left eye would close.
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But the Right eye would stay open because it was connected to the fully awake Left hemisphere.
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EFX – Northern fur seal colony on beach
Northern fur seals have taken this adaptation to another level. Since they live both on land and in water, fur seals have different strategies for sleep depending on where they are.
When sleeping on the beach, they can allow both hemispheres of their brains to lapse into a deep, long brain wave sleep.
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But fur seals can spend weeks at a time feeding in the ocean. When they’re out in the water, their brains switch to a completely different sleep strategy. They go to sleep floating on their sides – one hemisphere staying awake to hold their nose up above the surface to breathe, while the other hemisphere gets some well-deserved rest.
Interestingly, they always sleep on the side with their closed eye – the sleeping one – facing the sky, and the open eye – the awake one – looking down into the water.
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No doubt they do this to better spot Orcas, sharks or other potential predators from the deep. We assume that it didn’t take long for fur seals to learn the value of sleeping with one eye open!
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Phil Stieg: More recently, with the advent of functional MRI, we’ve been able to define something called the default mode network. Can you explain to us what that network is and its relevance to both dreaming and to daydreaming.
Robert Stickgold: Yes. The default mode network has a very funny origin because when people started doing functional magnetic resonance imaging, fMRI, which lets us see the parts of the brain that are active at any given moment, they started having people do all sorts of things in it. Do these math problems, do this visual task, do this auditory task. And happily, they would see visual cortex light up. They would see auditory cortex, cortex meaning portions of the brain light up, just when you expect them to. But they noticed that at the same time, there were some areas of the brain that became less active, which makes some sense, but it was the same areas becoming inactive no matter what you asked the person to do, whether it was a math problem or a visual problem or an auditory problem, the same areas became silent. It wasn’t until almost a decade after this all started that someone said, Oh, my God, those areas of the brain are the ones that do what the brain does when it’s not doing anything.
It was, in fact, the default network. It was the network that was active when you weren’t particularly trying to do anything else. You’re walking down the street without Air Buds in. You’re riding in a car, you’re sitting at the table eating a meal, you’re lying in bed before you fall asleep.
These networks are the ones that are used to predict or to view the future. There are networks involved in recalling memory but also projecting memories into the future. They’re the ones involved in theory theory of mind. If you’re trying to figure out what someone meant when they said, Good luck with that, and you couldn’t decide whether they were saying, Good luck with that or good luck with that. So your brain is mulling over these things and trying to interpret them.
And so that’s the default network. And it comes on gangbusters when you go into rem sleep. So it’s that same circuit that we use when we’re daydreaming, that we use when we’re night dreaming. In sleep, we have the added benefits that A, we’re cut off from external stimuli, so we’re not being distracted, and B, the brain has the ability to change these neuromodulatory systems in ways that make it easier, more effective to do this searching of all the memories.
Phil Stieg: I was most interested in your conversation about the iPhone and social media’s effect on that network, and the implications about how that will affect our dreaming.
Robert Stickgold: I was talking just at dinner last night with friends about this wonderful book entitled “Rest as Resistance.” And the hypothesis is that our capitalist culture has inculcated in us a belief that if we’re not being economically profitable at any given moment, that we’re being lazy, that we’re being bad, that we’re bad people, that it’s not okay to take time off and rest. When you plan your on a vacation, you plan every minute of it so you don’t waste any time. I mean, the whole concept of wasting time on a vacation is an oxymoron because that’s what you’re supposed to be doing.
And so now we live in a culture where people wear Airpods all the time. They are never alone with their own thoughts. As with any situation where you avoid thinking about things. When you allow yourself to think about them, what tend to come up are the most important and the most problematic. That reinforces this desire to avoid being alone with yourself. But that’s an incredibly important time. That’s the time our brain gets to contemplate.
Phil Stieg: It’s called “living life.”
Robert Stickgold: Yes. Yes. Thank you. It turns out that this is particularly apparent in the time just before you fall asleep. Because if you think about what goes through your mind as you’re lying there in bed, it’s what didn’t I get done? What do I have to do tomorrow? What happened today that I don’t understand? All these things that the default network is incredibly efficient at trying to answer. Those are the thoughts that we have as we fall asleep, and those carry on into our dreams of the night.
Phil Stieg: So your comments lead me to the next question then, and that’s the relationship of the default mode mechanism or network to insomnia. What’s actually going on with insomnia and how does that affect your dreaming?
Robert Stickgold: I can answer the first half, and I don’t know that I can answer the second. What happens before you fall asleep as you’re lying in bed. In what I believe is this carefully evolved psychological state designed to help us preview for our brain what the topics are that it needs to work on during sleep, both in dreams and outside of dreams. When this is working properly, you remain in a very calm state. This evolved pre-sleep state also evolved to tamp down emotions, and sometimes it fails. So when you’re lying there in bed before you fall asleep and you say, “Oh…I was supposed to send that email out today. I’m going to have to send it out tomorrow morning.” That’s fine. But when it’s something you say, “Oh, my God, I forgot to send out that email!”, and it breaks through into this emotional state. You get a big pulse of adrenaline release, and it takes the body 15 minutes to break down that adrenaline.
When that happens, You’re going to lie there in bed for the next 15 minutes, unable to fall asleep. If during that time you say, “Oh my God, I’m not falling asleep! I’m not falling asleep! I’m going to be a disaster tomorrow”. Then it releases another bonus of adrenaline. That’s now thought to be the main cause of insomnia. It’s this breakthrough anxiety around pre-sleep thoughts. How that affects our dreams per se, I don’t know. Whether that leads to nightmares, I don’t think we have evidence of.
Phil Stieg: Let’s shift gears a little bit and talk about the difference between nightmares, sleep terrors, and just the plain old bad dream. Bad dreams. Yeah. What’s the difference and the significance?
Robert Stickgold: So night terrors come mostly in your deepest stages of non-REM, non-rapid eye movement sleep. They occur primarily in children. And when they wake from them, there’s no story associated with them. They’re called night terrors because they’re not dreams. They don’t wake up and say, Oh, there was a monster chasing me. They wake up and they’re just in terror, and there’s nothing cognitive, psychological, conscious associated with it. We don’t know why they happened. They don’t seem to have any deleterious effect on the individual. They don’t predict other types of disorders, and you usually outgrow them relatively quickly. Those are non-REM, in fact, deep non-REM sleep and unassociated with dreams. But they’re terrifying. They’re terrifying. Bad dreams are just what they sound like. You have a dream that’s very upsetting. And when you wake up from them, you say, “Oh, God, that was a terror. I wish I hadn’t had that.“
Phil Stieg: All right. So teach me, Obi Wan, how to improve my dreams and my dream quality and my dream life.
Robert Stickgold: I don’t think you can. I don’t think you want to. I think that we’ve been evolving this dream mechanism for tens of millions of years. And I can’t help but believe that evolution has done a better job than we can. Having said that, I’m going to take it back because it turns out that especially at sleep onset, we can direct our dreams in valuable creative ways. Salvador Dali did this. The whole movement came from him getting images from dreams. Thomas Edison had a chair he would sit in. He would sit in a chair, an armchair, with his arm on the arm of the chair, holding some keys in his hand over a tin pan on the floor. And he would go to that chair when he was having a problem with some invention he was working on. He couldn’t figure out how to do some part of it. And he would sit in his chair and he would take a nap. And when he fell asleep, the muscle tone in his hand would relax, the keys would drop, they would hit the pan, they would wake him up, and he would insist that 90% of the time he had this solution to his problem. Salvador Dali was very funny. He wrote a little essay on this where he said, This creative process occurs in the quarter second it takes the steel balls, which is what he held in his hand, to fall from my hands to the plate on the floor. That it happens that fast.
Phil Stieg: Can you tell us, is sleep talking the same as dreaming, and then you’re verbalizing it while asleep, or are they separate entities?
Robert Stickgold: No, they’re very separate entities. First of all, sleep walking and sleep talking tend to occur during the deepest stages of non-rapid eye movement sleep. It’s a completely different mechanism. If you wake people up after they’ve been sleep talking, they have no memory of it. That seems to be a different process. Whether it is vaguely functional somehow, which seems unlikely because so few of us do it and those who do it so rarely, or just some mechanism slipping a bit and allowing those behaviors to occur.
For example, if you sleepwalk, you’re very oriented in space. You can get up, you can open the refrigerator, you can get something out, you can eat it, you can go back to bed and fall back to sleep with no memory of it. In contrast, if you have what’s known as rem sleep behavior disorder, which is where that paralysis of rem sleep breaks down, then you act out your dreams. You get up and you run full speed into a plate glass window, or you fight off this attack who happens to be your spouse. A lot of the early hospitalization reports that resulted from rem sleep behavior disorder were misdiagnosed as spousal abuse. A woman would come and she would say, He beat me and beat me during the night. But he was asleep! He didn’t know what he was doing. He would never do that. The ER docs would shake their heads and say, and write it down as spouse of abuse, because that was the only explanation they had.
Phil Stieg: Okay. As a clinician, then, I have to ask the final question is, where do you see the therapeutic value in the future from greater analysis of dreams and a greater understanding of what dreams mean? Where will it be applicable in medical care?
Robert Stickgold: So dreams can tell us things that we know and don’t know we know. Someone came to me and said, “Bob, I had a prescient dream. I had a dream that predicted the future. I dreamt that my father died. And the next morning, I got a phone call from my mother, and he, in fact, had a heart attack and died during the night. Bob, it’s not like he was dying or something.
In fact, I had talked to him yesterday, the day before, and he told me that he had just played one of the best games of tennis of his life, and that afterwards, for an hour, his shoulder was incredibly sore”.
It is a fact that shoulder pain is a sign of a heart attack. I would argue that she knew that but had forgotten it. But as her brain goes searching, as it does during the night, For remote associates to what happened in the day, the brain identifies, Oh, shoulder pain, heart attack, father dies.
So the brain can, in fact, predict the future by using information that we already had but didn’t really understand. And it might be that it can predict illness in oneself. People will tell you, I was having all these bad dreams about my stomach, and then it turned out I had stomach cancer. I believe that. The trick is knowing what the dream is really about. Was she having dreams because she had stomach cancer? Was she having dreams because she was unhappy about gaining weight? Was she having those dreams because she was intensely stressed? That’s really hard to tease apart. But again, it’s network exploration to understand possibilities and not to give us answers. And as long as we keep that in mind, I think it can be used. It might be useful for diagnostics in a lot of areas.
Phil Stieg: Dr. Robert Stickgold, thank you so much for being with us.
Robert Stickgold: And thank you for having me.
