Robert Stickgold on the Mystery of Dreams and the Science of Sleep | Closer To Truth Chats

dreaming is a venture capitalist it's investing our time and its resources in all sorts of possibilities most of which might not pay off [Music] bob it's great to see you i checked the last time we spoke was uh in boston uh it was october of 2011 so we're heading up on our decade and i'm really fascinated to see what has happened in sleep and dream of search since i enjoyed our conversation then and i have to tell you i loved your book uh when brains dream exploring the science and mystery of sleep unfortunately i have missed a lot of sleep because i i was reading it the last few days but how long have you been working on the book well tony jojo and i uh we've been working on it it probably started out two and a half years ago and of course nowadays of the publishing industry they want they want copy edited version almost a year before they go to press so the book was really done almost a full year ago but we spent we spent a full year and a half writing it as well good so what i'd like to do is i you know have this book embedded in me and it's hard to be able to organize it but let's let's try to do it in a in a systematic way and we're going to focus on dreams for sure but let's start with the meloo in which dreams take place and then first of all talk about sleep so uh let's start with kind of the basic stuff about the stages of sleep and particularly what have we learned about them in recent years sure so while it might feel like when you're asleep you're just asleep you're actually going through a series of different stages it's about a 90-minute cycle you start with waking and then you go into deeper and deeper sleep for about a half hour 45 minutes and then your sleep starts to lighten and you come up to lighter sleep and after about 90 minutes you go into what we call rem sleep or rapid eye movement sleep and that's the state where our dreams are most intense most bizarre most visual most emotional and we stay in rem sleep and then we cycle down again we have this 90 minute cycle all night long where we're going in and out of rem sleep into deeper non-rem sleep up into rem street and as the night progresses we spend less of each cycle in that deep non-rem sleep and more of it in rem so while we've got this 90 minute cycle it's really marching towards more and more rem sleep um they differ in a number of ways they differ physiologically in terms of the brain activity if you're recording the eeg from the scalp measuring the brain activity you see these waves of oscillating activity and occurring in the brain which are very slow when you're in non-rem sleep and then get faster and faster until you're in rem sleep where you actually can't even see them anymore so the brain becomes much more desynchronized looks more like when we're awake when we're in rem sleep um other things change as well there's a lot of neuromodulators in the brain there's no adrenaline there's serotonin there's acetylcholine and dopamine which really sort of run the program that's being implemented in your brain at any given moment it's the same hardware all the time but these neuromodulators sort of say are we being focused are we letting our attention wander what's going on and those change from from sleep stage to sleep stage so that when you go into rem sleep the release of serotonin and the release of norepinephrine or adrenaline is completely shut off so you go into a very different neurochemical milieu where only the acetylcholine seems to be high and so that seems to help us process memories more effectively so roughly in a given night's sleep what percentage of time are we in rem so we spend about 20 of the night in rem sleep children spend more infants spend hugely more up to two-thirds of their night and run but basically once we get adolescents we're spending twenty percent of our night in rem twenty percent in the deeper stages of non-rem sleep and a full sixty percent in sort of like non-rem sleep okay of the non-rem sleep um uh which is 80 20 deep 60 uh you've divided into what you call n1n2 and n3 different stages and and they're more than just um specified that there are different physiological functions uh how deep can we understand those differences the difference or first of all the three stages the division between those three stages is somewhat arbitrary realm sleep is a is a qualitatively different state of sleep and we sort of draw lines um between the different stages of non-rem depending on how much of the time in any given minute we spend with really slow oscillations in the brain we don't know a lot about the function of these different stages we know that children growing up released most of their growth hormone during n3 the deepest stage of non-rem sleep and and we know that for memory processing during the night um a lot of our processing of facts that we learned during the day um that that information tends to be strengthened and solidified during m3 sleep while other types of learning like procedural learning of how to do things or motor tasks or visual tasks tend to be more correlated with the amount of time we spend with n2 n1 only comes on as we're just falling asleep and it's only two or three minutes long and when we talk about dream function we can come back and talk about what n1 is doing okay all right let's go into now we know the stages of sleep let's go into the physiological um purposes of sleep when people first started uh thinking about sleep they just thought it was just rest but as we've learned more there are some very distinct physiological uh activities going on so let's articulate those and then we'll go on to dreams okay so physiological functions of sleep what do you think housekeeping housekeeping so some of them some of them are housekeeping it turns out that we do a lot of processing of immunological systems of hormonal systems so we know for example and this is particularly relevant in the covid era that if we sleep the private subject after they've received say an influenza vaccination and then look at how much antibody they're producing two weeks later it's reduced 50 percent if they don't sleep the night after they receive the back solution so you really need that sleep afterwards and you need it before too they get the same sorts of results if they just restrict people to four hours of sleep at night for four or five nights before the immunization again you get almost a 50 reduction in how much antibody you produce and that's really the difference in many cases between being functionally immunized and not yeah i've had the experience in life where if i feel like i'm getting sick or getting cold uh and i go to sleep and sleep a long time in many cases not all i can avoid that and you know i've always wondered is is that a old wives tale or psychosomatic but it might be psychosomatic not in the placebo sense but in the real sense of your mind really affecting how antibodies are are formed yes and it's we don't know what that mechanism is we don't know how sleep is enhancing that but it clearly does and of course as everybody knows if they stop and think about it when you get a cold there is at this overwhelming drive um to sleep and in fact one of the best-known soundogens chemical substances that can tend to push you into sleep is to break down products of bacterial cell walls so if you get a bacterial infection your brain notices that and it tries to get you to speak more so not only is it helpful but your brain knows that and tries to push you into that state you've also talked about uh growth hormone being um amplified during sleep in fact you have some statistically just children very large growth can occur measurable in just one or two nights is that right you can grow close to a quarter of an inch overnight that's unbelievable that can you know when they first came up with this measurement and it was a nurse who did it because the doctors all thought they knew better but she actually saw kidzone um when they stopped to think about it if you take each spinal segment each spinal bone there's a growth plate at the top and the bottom of that segment that spinal segment and if each of those growth plates that's one cell division gets one cells thicker and you do that for the whole length of your spine it's somewhere between an eighth and a quarter of the end of an inch and so yes when when when parents say to their kids you're bigger than you were yesterday that can literally be true wow that's that's amazing and sometimes 80 percent of that growth hormone that's driving that cell division that growth is released during um those stages those times when you're in that deepest m3 and so it's differentiated even between the the different um segments of non-rem sleep not just between rem sleep and non-rinsing that's right that's right it's that deep m3 sleep that seems to be pushing the release of growth hormone how about the physiological process of memory consolidation uh well that's you know that's my that's my life story that's my life's work now um it turns out that the entire time we're asleep our brain is processing the memories from our day what i'd like to tell people is evolution has calculated that for every two hours we spent a week taking in new information it has to go offline for an hour so it can just step back and look at that information and figure out if you will what it means it's very easy to record something it's very hard to figure out whether it's worth keeping how it should be kept where it should be stored and in essence what it means and that's what the brain is doing all night long it's taking memories and stabilizing them it's making them stronger so that you can for example do some tasks you learned the night before faster more efficiently in the morning than you could in the evening before you went to bed it'll take an emotional memory and strip out all the background images in the scene and just hold the memory for the emotional core of that event if you're taking in a lot of related information it will take that information and look for patterns it'll extract just from it you can hold on to the gist and forget the detail or if there's some sort of pattern in the data it can discover that or the rules that control it all of this has happened while we sleep and much of this it doesn't seem to be able to do while we're awake that sounds like a great story but you know as a former neuroscientist myself i've got to ask you give me an experimental design that can back up what you just said okay let's take a simple task typing with your left hand up on the keys the sequence four one three two four okay it's sort of an ugly sequence that goes back and forth we'll have a subject type that as quickly and accurate as they can for 30 seconds rest for 30 seconds do it again for a total of 12 repetitions most people especially if you said like college student they'll start off somewhere around 18 in the first 30 seconds they'll check it successfully 18 times then after just three or four trials they'll be up around 23 or 24 and at the end of the 12 they will plateau maybe at 26. we do that in the morning we say thanks see you later we send them home they come back that evening 12 hours later we sit them down they have we have them do just two 30-second trials and where are they they're at 24 right where they ended when they finished training that morning if we flip the time scale if we train them in the evening they still start at 16 they still train up to about 24 at the end they come back the next morning and right off the bat they're 15 to 20 faster wow okay now maybe that's not sleep maybe that has to do with just the night but we can repeat this in a nap paradigm we can train them at 10 in the morning test them at 3 in the afternoon and give half of them a 90 minute nap and the ones that get the 90 minute nap will again be 15 to 20 faster at 3 pm the ones who don't nap will be exactly where they were at the end of training and if we look at the sleep especially with the overnight study will find that the amount of time they spend in n2 sleep late in the night is highly predictive of the overnight improvement in fact it explains 50 of the variance and how much improvement people show okay uh just to finalize the physiological benefits of sleep you've also talked about the kind of the cleansing of the brain from beta amyloid proteins which could be cause of uh alzheimer's uh other kinds of things by the cerebral cortical fluid kind of bathing that is that is that a a kind of a generalization or do you know that no we now know that and there's been more and more studies replicating that and we're really confident now while you're sleeping the cells in the brain actually shrink a little bit and when they do that they open up a lot more space around them and that allows the cerebral spinal fluid which really bathes all the cells uh in the brain and the spinal cord it gives it a lot more room and you get more motion of that fluid and the studies have been done and show that you get actual washing out of these beta-amyloid complexes that are indeed hypothesized to be a major contributor to the development of alzheimer's disease and might that mean because i spent so much time reading your book and learning so much that i have a higher percentage of maybe getting alzheimer's because i'm asleep the last couple nights not a couple of nights no if you need my book compellingly every night for the next five years that might do it okay i'm not doing it anymore but but it's been shown that your amyloid content will be lower in the morning than it was the night before if and only if you've slept and there's now a study out that came out in science i think almost two years ago now that shows that that increased flow happens during slow wave sleep and it actually happens in a pulsatile way that's timed to the actual slow oscillations so these small oscillations are going at about 0.5 to 1 per second so they let they take about one or two seconds to happen and you can actually in fmri see the pulses lining up with that actual electrical activity in the brain so the brain is pumping it out another important function we're discovering for sleep is that it seems to be involved in the regulation of insulin when people are sleep deprived for a couple of nights or put on four hours of sleep at night for four or five nights they start to look pre-diabetic their regulation of insulin goes off and it leads to an increase in weight uh it leads to more eating because the insulin regulation is off and ed van carter at the university of chicago has hypothesized that in fact much of the epidemic of obesity that we have not just in the u.s but around the world is not just caused by the food we're eating but the lack of sleep that we're slowly building up we know that when animals are sleep deprived they will die probably sooner than they would be by food depletion and there are you know world records of humans staying awake for 11 days or whatever but that guinness book of records i read in your book has been cancelled because that's really dangerous um so how how do you what are the the drivers that if we uh significantly sleep this pro deprived we can actually die we don't know the answer to that question and it's a fascinating one because it's been probably close to 40 to 50 years since it was first really cleanly shown with rats that if they are sleep deprived they will die all of them within one to two weeks and they've spent 40 to 50 years trying to figure out why they die and we don't know they tend to get infections it might be some kind of sepsis but that doesn't seem to be able to explain at all so it really is one of those remaining mysteries of sleep bob i'm really looking forward to talking about dreams i loved your book when brains dream exploring the science and mystery of sleep which largely focused on on dreams so let's begin with uh kind of a history of dreams and just from my perspective as a as an amateur uh at one extreme dreams have been the word of god uh joseph with interpreting pharaoh's dreams and daniel's prophecies about world empires and babylonian dreams the other the other extreme you have some scientists and i must say i've been sort of in that group thinking that dreams are an epi phenomena they seem like they're doing something but they're they're really the results of other kind of processes in in the uh in the brain going on the house cleaning effects that you have these firings going on the trigger thoughts and we we impute meaning to them where there's absolutely none then of course you have freud who gives all these uh psychological and uh and uh psychosexual meanings the dream kind of hormone falling so you have these vast extremes so give me a sense of of your approach to the history of understanding dreams well you know the the interpretation of dreams goes back to the earliest recorded stories uh in the world the the epic of gilgamesh from 4000 bc which is just filled with these dreams that usually his mother freud would like that his mother interprets but they're always messages from the gods and so for thousands of years that was the main interpretation of dreams that there were messages from the gods because they clearly feel like messages and they've got to be coming from somewhere and where could they come from but from the gods and so that was that was the idea until probably getting into the 1800s and in the 1800s in the 50 years before freud researchers actually started studying dreams the french the british some american researchers did really superb research on dreaming and what they seem to say is that dreams well not so much function but mechanism of construction is that they took things from our memories and and they found things related to those memories and they built stories out of them and they didn't talk much about function so back when it was the gods the function was that's how gods talk to us the function of the dream was to transmit that message for much of the 1800s they didn't have much to say about function until the very end literally until 1900 when freud came out with his interpretation of dreams and then freud did two things he talked about where dreams came from which was from our repressed desires and then he talked about the function of genes and what very few people know is that freud thought that the reason we dreamed was to keep us from waking up that the function of a dream was to take this repressed desire my intense desire to sleep with my mother which i never knew i had but freud assures me i had and when you're asleep our ability to sort of suppress these desires is weakened says freud and they start to leak into our conscious mind and so our our conscious mind frantically tries to cover up that desire by by changing the dream by that changing the desire from my wanting to sleep with my mother to my wanting to go exploring in a cave or something like that so that it wouldn't be so upsetting to me that it woke me up but the main function of dream construction was to suppress that that illicit desire enough to keep me from falling asleep and that view became dominant in western culture and it was dominant right up into the 1970s when alan hobson who was in neurophysiologist studying sleep at harvard um came up along with bob mccarley with his activation synthesis model and that's the model that said that dreams are initiated by the random firing of these giant neurons in the brain stem and this activity goes up and it hits our visual cortex and the brain has no idea what it means and as he put it the brain then tries to make any sense it can out of this nonsense and that becomes the dream and so they've developed this concept which really has spread through a good part of the culture that dreams are just random noise that they don't have any real meaning and it's interesting that hobson actually never believes that he believes that about what initiated the dream that's the activation part but the synthesis part of jimin he actually is very psychodynamic he actually believes that your brain looks at your memories and and finds things of importance and builds your dreams from those but he never talks about that half and so we end up with this new cultural belief that dreams are random um no intentional content and hence meaningless and that that really stuck in the craw of almost all dream researchers i remember when i first read hobson's paper i said to myself either this guy has never remembered one of his dreams or else he doesn't know what the word random means because we all know that our dreams aren't random i mean they aren't just like the this fuzzy static that we used to get on our tv screens if it was just random noise in our visual system they're well-formed images they're built into coherent stories the stories feel meaningful they feel related to our lives and so they obviously are more than just random nonsense and so there's been this growing beliefs that somehow these dreams allow the brain to do some kind of reevaluation of the recent past or some planning for the future or some consideration of future possibilities and this is what's been referred to as the cognitive model of dreaming which is also an affective emotional model because another thing that's clear about our dreams is a we dream about things in our lives that are emotionally salient to us when we're awake and b that the dreamers themselves have often have very high emotions within their structure let's talk about the content of dreams now um so get give me a sort of a broad view of some of the content categories that the vast majority of our dreams would fit in uh you know whether it's five six ten just the kinds of of specific um the kinds of general content in which any specific dream i i have can be can be put into okay so we'll start by talking about the form of dreams dreams except those very very brief ones that we have at sleep onset dreams are narratives they're stories it's not a powerpoint presentation it's not a static picture it's not a series of unrelated photographs it is a story that evolves over time that we participate in so they're narrative we're in the middle of the story we're embodied in the story it's hallucinatory we see it we hear it we feel it sometimes we smell or taste it although not very often and we move we move into our genes so all of those are sort of what alan hobson would call the formal properties of jews and they're hyper-emotional that's another characteristic and then when you start to look at the actual content they're usually populated with people uh we are very rarely alone in a dream and if we are alone in the dream we're usually aware of the fact that other people are missing it usually happens in a um [Music] in an environment in a in a scene that feels familiar but actually isn't when we wake up and look back at it we usually can't say oh that that's that's my bedroom where i lived when i grew up in the dream we might think it's that bedroom but when we wake up we say no it didn't look anything like that um we're delusional through all this that's another formal characteristic we actually believe that this is happening in real life that we're not dreaming despite all the cues that we get that it couldn't possibly be true but there's people in it there's interactions there's emotional emotions the interactions and the emotions tend to be more negative and positive but not by a large margin we don't do a lot of rational thinking we don't seem to have a lot of personal control over what's happening in the dream but it tends to be stories that feel relevant to our ongoing life they can involve people who we're having problems with or having good times with it can involve activities that we're engaged in while we're waking interestingly we don't dream about typing or zooming or skyping or watching youtube we don't dream about reading books we don't dream about writing these things that most of us spend most of our time doing during the day don't have any role at all in our dreams they tend to be stories about things that feel important to us let me tell you one of my most vivid dreams that i that i had i'm going to give you the background and you're going to be my my sigmund freud so i was running a company this was 20 years ago about 50 miles from where i lived so every day i had to drive 50 miles on the expressway the freeway so now so that was that's the setting and here here's the dream i have a friend is suddenly sick from the company and asked that i take him home on his motorcycle now i've never driven a motorcycle at all um and he tells me that i'm gonna have to drive because he can't drive the motorcycle and it's about an hour uh on the freeway to his home i tell him in the dream i said i don't even have a helmet and he said no you don't need a helmet uh because there's a second passenger who's gonna also be sitting with me on the motorcycle so now i'm sort of in a uh i'm saying can at least i use the surface streets because maybe then if i have an accident i i won't get we won't get his heart he said no no no no you have to use the freeway and then i i remember this so then i said what is the slowest speed that i can drive on the freeway what's the slowest let's he said 50 miles an hour and and then i said i'm not going to do it i'm just not going to do this then suddenly all at once about 15 or 20 people all from my company surround me and tell me i have to do it there's no they're going to insist that i drive him on this motorcycle without a helmet and i feel myself pressured and and almost willing to give in but then finally i feel myself resisting and say here's what i'm going to do i'm going to call uber and buy everybody in this crowd a free ride home now i i'm smart enough to know that i shouldn't drive that motorcycle but i'm not smart enough to know that i'm dreaming and this is all nonsense well i have to start by giving you the answer i give everybody who comes up to me and says here's a dream tell me what it means i always say robert you are one sick cookie that's my standard response that's no revelation yes and and then when the their face starts to crumble i laugh and i say i have no idea what it means to you and i'm not sure it even has a meaning so if i was to play freud which i hate doing i would say okay someone is asking you to take control and to move fast and to get something done that you know a you don't know how to do and b is dangerous feel like most of your life yeah yeah i'm going to tell you one more this is a shorter one uh so i'm in a taxi and vladimir putin is the taxi driver and i'm sitting in the back seat and i really want to talk to him and he seems like he wants to talk to me and so as we begin a conversation every time he talks to me he looks back to me and i'm now in this panic of which one is more important the opportunity to talk to vladimir putin and really understand what he says or the fact that his eyes are not on the road and i finally decide to say please don't look at me look at the road but again i have no idea that i'm in the dream and again i really have no idea i mean so i'm going to give a quick guess and then i'm going to ask you a couple of questions okay because that's the real way to do it so the quick guess again is you're put in a situation where you have an opportunity to get information um maybe related to a show you want to do maybe not i'm sure you're not thinking of it that way but here's a man you would love to get information from and there's a risk associated with it and how do you balance the risk of crashing against the the positive aspects of getting this information so that's my you know that's my real tax yes let me ask you a question send me your bills don't forget your bill for the psychoanalytic services well if it's psychoanalytic it's going to be really expensive but but not so let me ask you when you woke up what did it feel the dream was about um i you know i don't have that recollection i've i've remembered this dream so often and i it's hard to discern the experience of when i actually had it from when i've rethought about it over the years okay so now what does it feel like is it an anxiety dream are you scared or is it an opportunity the first one with the motorcycle definitely an anxiety uh at one point in my life i wanted to i thought i might before i could afford a car i thought i might buy a motorcycle i went down i sat on one and i said i'm never gonna do this never that's as close as i came um but i i remember the emotion i had during that dream has lasted my whole life maybe it was you know 20 or 25 years ago i don't remember but that emotion of being pressured to go on that motorcycle without a helmet um and and and drive fast and knowing it was a mistake but feeling myself being surrounded by people pressuring me that that that emotion has has has lasted and you know i'm pleased in the dream that i resisted and i came up with this uh magnanimous way of paying everybody's uber as this big very clever but let me ask you do you feel pressured by your co-workers to to do things that you feel are dangerous to to try new things to go in new directions that they want you to go in and you resist yeah normally it's the opposite i i want to go in new directions everybody says i'm not so um i'm i'm not sure so um look let's let's let's go on um and now move to um uh the different categories of explanations of dreams you've actually listed listed some in your book the different ways of of of explaining dreams as an evolutionary function or as you said dreams have zero adaptivity or biological function the opposite uh dreams help us solve problems or play a role in emotional regulation related to rem sleep i mean those are the categories you've talked about so how to begin to look at each of those categories and then later we'll get to what what you think the answer is from a research perspective dreams are horrifically difficult to study and they're difficult for two or three reasons one reason is it's always plagued with the question of are we talking about what a dream does the function of a dream or are we talking about the brain activity that happens to produce this um this dream as a side effect as an epi phenomena to give you a sense of what that means uh a cardiologist will put a stethoscope on your chest and listen to your heartbeat and tell you that you have this kind of a problem or that kind of a problem or that you have a clean bill of health that heartbeat is just an epiphenomenon the brain didn't evolve with an intention to make a sound that a cardiologist could interpret the brain the evolution produced a pump and if you got a pump it's going to make a noise every time it pumps and we have found a use for it so so we never know with dreams is there some basic brain process going on that serves a function or is it actually the dream that's doing something so a fundamental difference yes yes so we do something so so that's one problem problem number two is it's very hard to experimentally manipulate someone's dreams and even when we can we don't know whether the impact of that is through the person dreaming having the phenomenological experience of dreaming or whether it's just the brain activity that's being induced that we know must be producing uh that dream and so we're always sort of stuck with these caveats when we talk about you know what dreaming is doing um so then when we come back and we ask what is it doing is it doing emotion regulation um so we can look at dream content ross cartwright back in the last century did these wonderful studies um with women who had just gone through divorce and she collected their dream reports from rem sleep and then she looked and asked okay how often do their ex-spouses appear in the dream and in what role in in which dreams does the woman take a more dominant role in relationship to their ex-spouse and in which dreams is the ex-spouse domineering in the dream and she found that insofar as the women were dominant in their dreams with their ex-spouses if you look six months out they were less likely to be depressed and so she argued that these dreams when they succeeded when they managed to portray the the recently divorced woman in a positive and powerful relationship with her ex-husband that that was causally related to preventing them from developing depression now you have to take a step back as a scientist and say all we have is correlation we don't have causation we don't have a way to make half the women have those dreams and the other half not have those dreams so we can try to look at causality but those are the sort of arguments that say that dreams are in fact uh involved in emotional regulation and we know in fact that we dream about things that are emotionally distressing to us but also things that are emotionally exciting to us and we know that our mood tends to be more regulated in the morning than it was the night before so something during sleep is serving that regulatory function um and why not have it be dreams so again it's a little soft from a scientific perspective because as you know when we try to study consciousness it's a real hard nut to crack because we can't isolate the conscious phenomenology from the underlying brain function brain activity okay you have uh posed your own theory of the acronym next up network exploration to understand possibilities um as a new theory that you said opens our minds to unexplored possibilities uh that sounds like a very specific kind of um of purpose of dream so i'd like to have you describe it and then go into it in some depth including experimental evidence okay so the idea is when we're asleep we know that our brain is doing massive amounts of memory processing and most of that memory processing if we analyze it if we ask what is the impact of the sleep on those memories we describe it as as convergent thinking processes that is to say it takes a bunch of information and tries to come and find the central meaning of it it tries to find the gist of an extracted gist or it tries to take word pairs that we have memorized the night before and strengthen our memories so in the morning we're better able to remember the second word in the pair when we're given the first word that they're very goal oriented in a very specific kind of a way and that's important and that's very helpful to the organism makes the organism better prepared to face the world the next morning because it has this extracted meaning in some cases and this increased strength of the memories and this better ability to perform tasks as a result of sleeping there's this nice phrase um memories about the future not about the past uh that you that you have in the book that's right and that actually comes from dan schachter who said that we tend to think of memories as being about the past you know when we get older and we're in our rocking chair we can say remember remember when we were younger and we did this or that but that's not why memories evolved memories evolved that when we find ourselves in a situation in the future that we've lived through in the past or that's similar to something we've lived through in the past we can learn from our mistakes and that's what's memory is about so that we don't repeat failed patterns so that we can take knowledge that we've accrued in our memories to project and predict what kind of behavior will be most successful in the is very future with a a kind of a recent theory of brain function in general that the brain is a predictive organ and you can do there's a lot of work showing in in sensory work between afferent and efferent fibers that the brain is imposing ideas on sensation uh and the underlying theory is that this is a predictive the brain is always predicting something and then matching the reality against the prediction and then modifying its prediction so if that's a a core kind of fundamental approach to the brain then what you're saying in memory is very consistent with that right but notice that we're working over huge scales of time so the brain sends a signal to a motor afferent to cause a muscle to contract it gets feedback from appropriate receptor to say how much the the the limb for example has moved it says that's not what i meant to happen and so next time it wants to create a motion it'll send a stronger impulse and all of that is happening almost on the millisecond basis and the same with the visual system it's all our sensory system so it's it's doing this fine tuning so that it can predict what's really happening in the outer world more and more accurately and it's doing it on a fraction of a second basis and then we have the kind of overnight processing of memories that that i've been talking about mostly for the last 20 years which is non-conscious not dream related memory processing and that's working on a scale of hours right i'm going to be better at this in the morning than i was the night before but it is something that the brain has identified and we can talk about this more that the brain has said you know what in the in the near future hours to days this information would be valuable if i could make it more predictive if i could be better able to predict which card is going to get turned over in the deck next so so that's on that scale when we're dreaming we're really talking longer scale so i sometimes say dreaming is a venture capitalist it's investing our time and its resources in all sorts of possibilities most of which might not pay off you know venture capitals we say that if a bench if half of the investments of a venture capitalist turn a profit they're not a venture capitalist they're looking for 10 of their investments turning a thousand percent profit and then they're happy so when we dream our brain does something very different from what's doing in the non-conscious memory processing during the night it looks for strangely weak associations so something happens in your day i'm driving home from work i live in cambridge massachusetts some jerk runs a stop sign and almost crashes into me i have to swerve into oncoming traffic to avoid being hit fortunately there's a break in traffic i get around fine you know i make it home safely i tell debbie my wife i'm going to take that job in iowa i'm done driving in in boston that night i have a dream and in my dream i'm at the amusement park with my son adam and he's five years old and we're on the bumper cars and he's driving the bumper car and he's crashing into everybody he can and everybody else is crashing into him and he's laughing and laughing and i'm sitting there saying i don't want to be here this is not fun now i don't remember about the near accident i was in yesterday that doesn't come to my mind because in rem sleep specifically outflow from the hippocampus is shut off so we can't reactivate actual memories from the day before um and i certainly don't replay that memory which the brain is going to do for me as soon as i wake up and so i wake up and i laugh and i said i just had a dream about that accident i was almost in and if i want to i can stop and say what the hell was my brain doing i mean those are totally different situations i mean one was really dangerous the other one wasn't really dangerous at all and if i think about it maybe i say well actually you know the car coming through the stop sign wasn't as dangerous as it felt at the time was it i mean if he had hit me it would have been an insurance claim you know i might have need to go i needed to go to the chiropractor he wasn't going fast enough that he would have flipped my car or hurt me seriously it was just scary so one could argue that the brain wasn't trying to give me that message it was saying okay you had this really upsetting event during the day let's find things that seem related to it what's related to it and one of the things that comes up with is bumper cars in the amusement park and it puts me into that scenario and it runs me through it and it watches my brain watches me the character react to it and get all upset and my brain looks at that level of upset and says okay this is valuable this is important because he's reacting strongly to it i'm going to connect it to what happened during the day i'm literally going to strengthen the synaptic connections between nerve cells that go from the event of the day through my associative networks to being at the amusement park so that when i'm awake tomorrow even if i don't wake up and remember the dream those connections will be stronger and if i think about the accident i might say although it really wasn't that dangerous and have no idea why i'm saying that because i don't remember having the dreams exploring and then strengthening weak associations is i think the key element of the the next uh theory that that you have network exploration to understand possibilities now you have a priming experiment which is very specific in showing how weak associations are strengthened in dreams and in in my knowledge that that is that that seemed to be one of the most powerful experiments all the other theory is great i love to hear it and stories but that experiment is is is is counter-intuitive and unexpected and and the results seem to be extremely significant yes so this is a wonderful old cognitive psychology test i'm going to flash a word on a screen maybe the word wrong and half the time i'll flash a word and half the time i'll flash a non-word it might put up w-r-o-n-k instead of w-r-o-n-g and then when that comes up i say press one of two buttons it's a word it's not a word do it as quickly as accurate and as accurately as you can and then the trick of the study is that before each of these words a quarter second before that word pops up i flash another word on the screen so i might put up the word fox and then wrong and see how long it takes you to respond to the word wrong or i might put up the word thief and then wrong or i might put up right and then wrong and if i put up right and then wrong you will correctly identify wrong as a word faster than if i go thief wrong and if i go thief wrong you'll go faster than if i put up mop wrong so we can take an unrelated word prime and look at how much faster a weak associate and the strong associate makes the brain and we're literally seeing how when you see a word like thief or wrong or even mop your brain automatically starts activating associated words in your brain as if it's getting ready to hear this next word so i can say here we go robert right wrong fast slow high low fat and your brain just wants to say thin it's like it's it's activated automatically and so by looking at how much faster you go you know how strong those connections are at the moment and i say at the moment because when you wake someone up from rem sleep and run them through these these word pairs this priming task and we can get them through 50 of these primes in just two minutes while they're still waking up we find that they respond to thief wrong faster than they do to right wrong all of a sudden the weak the normally weak associates seem to be more strongly connected so when you're in rem sleep your brain is going to preferentially be following those weaker pathways that's an amazing result and really it's the the core experimental uh uh evidence for your your theory when i first read the theory i said oh that's nice and you know i know a thousand other theories that maybe thought i thought were nicer but that experiment you know shocked me so that was a great one and what's interesting about it historically is that we use that task because that's the result you see with schizophrenia patients schizophrenia patients are notorious for being hyper associative you start them talking and they're just all over their place they can't they don't seem to be able to follow a straight line of conversation if you just let them talk they'll just go oh i was talking to my mother which rhymes with brother and i haven't seen my brother in months and that reminds me of lunch and they'll just keep going off all these different tangents so we thought there's something about this schizophrenic brain that allows it or causes it to preferentially follow these weak associations and of course we know from our looking at our dreams that we have all these bizarre events happening in our dreams well what i want to do now is to give you a series of words and get your immediate association with each one in terms of of dreams and make it each one very short i want to get your association so let me just start and give and give me a sentence or two on each and i'm just going to go through the list okay start bizarre dreams our dreams are incredibly bizarre they are not like completely irrational there's always some sort of logical connection there it's just not one we expect to see nightmares we don't know whether nightmares are a successful use of dreams or whether it's a dysfunction of dreaming it might be that they let us process those bad memories more effectively do children dream children's dreams are a lot more about animals than ours are as adults they seem to have a somewhat simpler form but they can be equally emotional equally distressing and equally exciting do animals dream if they're conscious they probably dream lucid dreams where you're in a dream and you know you're in a dream and you can manipulate it in some way uh i i i would like to do that i never have i know you have some instructions i may try it lucid dreaming is actually just being aware of the fact that you're in a dream it doesn't necessarily require that you're able to change the content of the dream most people will report that they've had one or two lucid dreams in their lives there are some who have them every month and a small number who have them every week or even every night the ability to control what happens in the dream is difficult because when you're in a lucid dream you're sitting on a knife edge and on one side is waking up and the other side is losing lucidity so you first have to learn how to navigate to stay on that edge and if you can do that then you can start playing with manipulating content interestingly everybody's first choice is not sex with a movie star it's flying uh the relationship between dreaming and lsd experiences and the sort of the acid awareness that people have talked about one of the strangest things that bothered me for years about dreams is this phenomenon that everybody thinks their dreams are really fascinating and exciting and important and they really want to tell me when i go to parties i don't tell people i'd study dreams anymore because if i do the next seven words out of their mouths are oh i had the most amazing dream and then they tell me a totally unamazing in fact boring dreams so what is it across thousands of years across every culture we have ever looked into why does everybody think their dreams are important the only place i know that that happens outside of dreaming is in people who take lsd as someone who lived through the 60s 1960s i can tell you that we called these acid insights and i remember someone saying to me i wrote it down this time because i i never remember it correctly and here's what i this here's my insight when you flush the toilet everything underlined underlined underlined goes down and he paused and he said no it meant more than that it really explained everything and what i realized is that when you're in rem sleep we know that the release of noradrenaline norepinephrine is shut off in the brain completely and we know that that will loosen our associative networks because of course when your adrenaline is high you're amazingly focused and if you can get rid of that it allows your mind to wander but serotonin release is also shut off reason for that we haven't had any good explanation for it but lsd is a serotonin mimicker in some parts of the brain it actually causes more serotonin release in other parts it shuts off serotonin release and my clinical use of dreams okay sorry um let me say one more sentence about the other thing and i'll make it really fast i think the shut off of serotonin release in the brain during rem sleep is a mechanism the dream that the dreaming brain has to make us think our dreams are important even when they're not to bias us towards assigning value to these weak associations that we would otherwise just reject clinical use of dreams i'm not sure what the clinical use of dreams are we can use various techniques to work with people who have nightmares we can try to work with people who have ptsd and these repetitive nightmares um i'm not so sure that we can do more with dreams except use them in sort of a talking therapy to help us gain some insight in into our psyche and our our deep thoughts and beliefs telepathic and pre-cognitive dreams uh so-called esp through dreams i think the esp of dreams is is part of that that serotonergic shutdown telling us that things are important whether they are or not i think we see lots of coincidences in our lives and assign meaning to them and when we dream them we assign more meaning but beyond that when we dream our brain lets us look at things that we've learned that we didn't pay attention to someone has a dream that their father dies and then gets a call in the morning and in fact their father has died and she tells me but the day before i had talked to him and he was incredibly healthy in fact he said he played the best set of tennis in his life he prayed so hard his shoulder ate all afternoon and i said to her did you know that an aching shoulder is a sign of a potential heart attack and she looked at me and said no but i suspect somewhere hidden in her brain was that information that she had learned and filed the way and it took her dreaming brain to find the association and play it out so sometimes our dreams do predict the future because the brain is after all a prediction machine folk wisdom has creativity and insights coming from dreams and i know from my dreams i've you know all the thousands of new ideas that i've had none of them were really any good we know that there are cases where dreams have provided profound insight we have two or three nobel laureates who ascribe their um their award to insights they gained from dreams again dreams that they recall that we don't recall more than about five percent of them but salvador dali had a technique for using sleep onset hypnagogic dreams uh to get images for his paintings thomas edison would sit in a chair an armchair with his hand extended holding a spoon over a metal plate and he would sit there and close his eyes and think about a block he had towards solving some problem in an invention he was trying to construct invent and as he fell asleep the muscle tone in his fingers would relax the spoon would fall and hit the plate rake him up and he said he would reliably wake up with an insight into the problem he was trying to solve this is the sleep onset period for both of them might have been sleep onset for some of those nobel laureates as well that's a time that seems to let us be particularly creative in discovering specific solutions to specific problems late night rem dreams dreams you remember when you wake up in the morning don't seem to work that well it's a hard experiment to do well i'll try my best i know you your book is terrific has a lot of advice about how to do this i will try and hopefully before another 10 years we'll get together and uh and and take another look at sleeping dreams well i look forward to it in the meantime sleep on everything i've told you thank you for watching if you like this video please like and comment below you can support closer to truth by subscribing

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Keywords: closer to truth, robert lawrence kuhn, robert stickgold, bob stickgold, why do we sleep, science of sleep, When Brains Dream, what are deams, understanding dreams, what do dreams mean, what does my dream mean, why do we dream, lucid dreaming, neuroscience dreams, neuroscience of sleep and dreams, rem sleep, what are dreams, science of dreams, are dreams important, stages of sleep, sleep and dreams, stickgold sleep, closer to truth chats, ctt chats, what is dreaming

Id: nVkSwvm8DU8

Length: 65min 34sec (3934 seconds)

Published: Thu Mar 25 2021