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Dreaming (part 3) with Antti Revonsuo
185 Plays26 days ago
Rolf and Joe wrap up their 3-part series on dreaming with Finnish neuroscientist and philosopher Antti Revonsuo. Dr. Revonsuo is the originator of the Threat Simulation theory of dreams, which suggests that dreams are simulated worlds in which we may practice threatening situations. Topics include the history and methodology in dream research, how our brains create simulated worlds, the particular nature of the simulated dream world, and how this applies to waking consciousness. We base our discussion on three forthcoming papers:
Revonsuo, A. (in press) Toward a Metaphysics of Consciousness: Science and the Fundamental Nature of Subjective Experience. To appear in The Scientific Study of Consciousness: Experimental and Theoretical Approaches. (Springer Nature).
Revonsuo, A. & Tuominen, J. (in press) The Concept of Dreaming as a World. To appear in Threshold Worlds (Oxford University Press).
Revonsuo, A., Valli, K., & Tuominen, J. (in preparation) Evolutionary Simulation Theories of Dreaming.
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Transcript
Introduction to Cognation Podcast and Dream Series
00:00:07
Speaker
Welcome to Cognation. I'm your host, Joe Hardy. And I'm Rolf Nelson. So today we'll be wrapping up our three-part series on dreams. In our first episode in this series, we talked about theories on why we dream, and we talked about a novel theory by David Eagleman that suggests that dreams are a way to protect visual areas of the brain from being taken over when there's no visual input.
00:00:29
Speaker
In our second episode, we talked with Pilarin Sika, a researcher at Stanford who shared her work on dreaming during anesthesia as a treatment for PTSD.
Meet Antti Revonsuo, Dream Expert
00:00:38
Speaker
Today, we talked to Ante Rivansuo, a Finnish cognitive neuroscientist, philosopher, and psychologist who has done work on understanding the function of dreams and also relating it to one of our favorite topics, consciousness.
00:00:52
Speaker
Antti Rivanso is a professor of cognitive neuroscience at the University of Hovda in Sweden and of psychology at the University of Turku in Finland.
What is Threat Simulation Theory?
00:01:03
Speaker
His work focuses on altered states of consciousness in general and dreaming in particular. He's best known for his threat simulation theory, which states that dreams serve the function of rehearsing threatening situations in order to aid survival. Rivanso completed his graduate education at the University of Turku receiving his master's degree, a licensure in philosophy, and a PhD in psychology there. He's written two books on consciousness, one called Inner Presence. Consciousness is a biological phenomenon in 2006, and then Consciousness, the Science of Subjectivity in 2010, as well as many peer-reviewed articles. Today, we'll be discussing his work on threat simulation theory, as well as on consciousness.
00:01:47
Speaker
We're basing our discussion on three of his forthcoming papers, all of which we'll put on the show notes so that you can check them out when they're published. Welcome, Auntie, to the show. Thank you. Great to have you here.
Antti's Journey into Dream Research
00:02:00
Speaker
Let's begin by talking about how you got interested in psychology, consciousness and dreaming. Yeah, I think it it can be traced back to my some of my own dream experiences actually already when I was a teenager. I had some dreams that I now know or later realized that they were what we would call ah false awakenings or pre-lucid dreams, where i in the dream I woke up in my own bed and then I started to do do things and and explore the world and then I noticed weird things. And i at some point I woke up again in my own bed and then I just was so like amazed that what was this world where I just woke up and was going around
00:02:47
Speaker
and going about and I just woke up now here. So is this the real world or or or is it not? So these dream experiences, they were always in the back of my mind as some kind of a big mystery that I always thought that, well, I really want to figure out what we know about dreaming and how is it possible to have such realistic experiences of being in some other kind of a world that that what's going on here. So this, I believe, was the initial motivation for me to start asking these kinds of questions about dreaming and consciousness as well. And then when I started to do my I mean, I was doing my master's on on studying information processing speed in Parkinson's disease and
00:03:36
Speaker
attention and things like that. So kind of like cognitive neuropsychology. But then I got to an opportunity to to go to a philosophy project to do my PhD. And I realized that there I got quite free hands what what to actually do there. So I started to gear my research interest more and more towards consciousness.
00:04:01
Speaker
And then I kind of smuggled in a little bit of dream research as well, because none of my supervisors knew anything at all about dreaming or dream research. So I kind of kept a low profile and was flying under the radar with my dream research. And I thought that, well, if it doesn't ever come to anything, I won't tell anybody I tried. But but if it comes to something, I will try to publish something and and then I will already be like a dream researcher. So that's...
00:04:30
Speaker
That's how it somehow came about.
The Evolution of Dream Research
00:04:33
Speaker
and And what was the status of dream research at the time, or at least you know if we're talking about what the function of dreams is, um what were what was the thinking about that at the time when you started? Right. I think I was greatly inspired by by a book ah by Alan Hobson, his 1988 book, The Dreaming Brain, because that was the first book that I thought that, okay, this is somehow a properly scientifically based book. And there was also, he was describing there some of his studies on dream content. I mean, his theory is mostly neurophysiological. So he's trying to, I was trying to kind of reduce dreaming to neurophysiological features of REM sleep.
00:05:21
Speaker
But he was still doing also what what we could call content analysis of dream reports and systematic collection of dream reports in the sleep lab or or or in home dream reports. So so then I realized, OK, there is some kind of systematic scientific way to actually study dreams and dreaming. and And I thought that this doesn't look like too difficult. Maybe it is something I could try to do at some point. So so that was a really big inspiration for me. And he had also been studying the bizarreness of dreams. So so what what is different from the waking world and waking perception in in dreaming? What kind of events and perceptions and people and objects and places we encounter in our dream experiences that are highly unlikely or physically impossible in our
00:06:19
Speaker
real world. and And this was also what I took to be the topic of my first empirical dream research, that i that I wanted to study this a little bit deeper, but I was very much inspired by how Hobson's group had approached this problem of the business of dreams and how to measure it, how to describe it. Yeah, and it's it's interesting, you know, the work that you have done, in particular, the the manuscript that you shared with us about threat simulation theory and social simulation theory, putting it in an evolutionary context. i you know Could you speak a bit about that, about how you sort of think about dreams as being something that must have evolved and how that might inform how we sort of approach the science of of dreams and dreaming? Yeah, I think also the original, originally the interest came somehow
00:07:18
Speaker
at least partly from from my own dream experiences, because I noticed that they were very often taking place in in in an environment that was kind of natural environment and and and somewhere like like ah where I spent summers closer to nature in our summer cottage or somewhere. And I i noticed that that this kind of environment seems to seems to be something that my dreams like to present to me a lot. And also there were often often these sorts of things like wild animals or storms or floods coming coming to our ah summer place. And I thought that there is something something weird. Why are these dreams somehow so repetitive? And I have had them since childhood. And so I did pay attention to that that a little bit. And then I also was course ah part of my studies where
00:08:15
Speaker
in I did a minor subject in biology and my father was a biologist, so I had quite much influence on sort of biological and evolutionary thinking. And I also started to read, at that time, what what was a very new approach, evolutionary psychology, cospy and tumidus, articles and books. And then somehow something started to click that, okay, so So if if many psychological and cognitive functions make more sense when we place them in an evolutionary context, that we kind of understand why currently we have these sorts of whatever emotional ah experiences or made selection strategies or whatever other the other major topics in evolutionary psychology, then it just somehow
00:09:08
Speaker
occurred to me that, well, maybe we should try to place dreaming in that sort of a context too. And it somehow started out from there.
Dreams as World Simulations
00:09:19
Speaker
and And then when I came up with the idea that we should define dreaming,
00:09:25
Speaker
as a virtual reality or as a world simulation, that it's actually a sort of a simulation program that is running in the brain, that if it is a pre-programmed feature of the mammalian brain, then why on earth would would that be there and why why would it have been preserved during evolution?
00:09:49
Speaker
And my thinking went then to, okay, so what do we use technological virtual reality simulations for? What what what what are their best and ah most valuable in doing? and and And I came up with this analogy to flight simulators because they they are like the most technologically advanced and most realistic simulators that are being used for some highly useful purpose to train pilots to to actually manage like like different kinds of situations and to learn how to how to fly some new model plane. and And they have to do this regularly. And it's perfectly safe to do it, even if you simulate all kinds of horrible things ah happening on flight, that suddenly everything is beeping red and you need to have the strategy how to do it. And then I thought, OK, but maybe this is this is the sort of function that Mother Nature came up with, that
00:10:49
Speaker
While consciousness is not doing anything useful, why keep the lights completely off during sleep? Maybe it would make more use of of of consciousness during sleep to run these kinds of simulation programs, which would be then useful for kind of like priming, rehearsing, activating, reactivating situations that have to be ah like fully prepared to face real situations, but we don't get that much practice because the practice itself would be too dangerous. So so we can't wait for meeting the lion in real life and then
00:11:37
Speaker
take some practice sessions because that that would probably end up very very quickly and you wouldn't wouldn't have any time to get a lot of practice before you were already eaten by the lion. So so you should so so so that this is how how my thinking kind of developed along those lines that, okay, so if dreaming is a world simulation,
00:12:01
Speaker
This could be the reason why why it is actually actively programmed as a feature of the brain and was programmed also already before humans in at least the mammalian brain. And then there could be like species specific simulations run of those kinds of functions which are most useful for survival for each species. and And therefore, human dreams are probably only partly similar to some animal dreams, depending on their role in, for example, are they predators? Are they prey? Are they social? Are they solitary? And so forth. So so this was these sorts of thoughts I had when I started to develop the the threat simulation theory.
00:12:54
Speaker
So okay, so it's fascinating to think of the idea that what our brain is doing during sleep is it's creating an entire world or it's simulating an entire world. um And you've talked about this as as something that can inform us about the way that the brain constructs our world for us in everyday life too, that this is continuous with normal everyday consciousness. So um Maybe you can talk about what the differences are between the kinds of worlds that are produced in a dream versus the way that we the way that we construct a model of the world in waking consciousness. Right, so so so I have kind of connected theoretically the
00:13:39
Speaker
too phenomenal at what we call dreaming and what we call waking consciousness so that they they have a similar mechanisms in the brain and that they both appear to us as a kind of a being in ah in a world experience that both during wakefulness and dreaming, I mean, we find ourselves in in the middle of of a world. And of course, if we are just lay people with naive realism in in waking perception, we of course take the world that is surrounding us and what we sort of supposedly directly perceive as being the real physical world. But but when you when you do some perceptual psychology and and neuroscience, then you start to realize that this must be a construction of the brain. And therefore the difference between what we the world that we experience during dreaming and the world that we experience during wakefulness is is not the
00:14:38
Speaker
the world itself so much as it is the input that is used to construct the world. So that during wakefulness, this world simulation is modulated by sensory input so that it tries to fit find the best fit with the sensory input and therefore construct a world that is functionally useful in navigating in in the real world, so that you don't bump into physical objects in the environment, for example, because your conscious model of the world actually shows you where the layout of of of different objects in in space. ah But during dreaming, then the the world that we experience is constructed internally from internal sources, which
00:15:33
Speaker
which use our memories, but also create a lot of like new kinds of situations. So dreaming is not replay of memories, at least not in any obvious manner, although it does use memories to construct different kinds of simulations,
00:15:58
Speaker
about different kinds of situations, manyu of which are well many of which are threatening situations, there is something dangerous going on, or and many of which are social situations, so that we are very rarely alone in our dreams, but but there are other dream characters, other people usually around us. so so And one of the differences is what we formally call in dream research, the bizarreness of dreams. So bizarreness exactly refers to those events or percepts or anything that we experience during in in the dream world that would be highly unlikely or even physically impossible to experience in the real world. So that is like like one branch in in the content studies of dreaming to try to actually
00:16:59
Speaker
map out in detail that then what and how how much of the dream world is actually quite coherent with and and consistent with the waking world, and then what kinds of like deviations from from our waking expectations happen. and and do we have Can we also theoretically explain why why that is the case?
00:17:25
Speaker
And one feature, one feature too, and I think you talk about this too, I mean, so this feature of bizarreness, but things don't actually feel bizarre in the dream
Immersive Experiences in Dreams
00:17:35
Speaker
state. So we're, so we're sort of suppressing this. um um There's a lot of things that we're not aware of in a dream. And and it seems as though that's being suppressed. Yeah, right. That that is, that's that's actually something. Yeah, also theoretically, important. And we we we have called it the Oblivious Avatar, that that we lack the ability for reality testing, we lack, to a large part, access to also to episodic memory or autobiographical memory. And that, I believe, the explanation is that this is also a crucial aspect of the function
00:18:22
Speaker
of dreaming as as a simulation, because if it were the case that we would have full reality testing and full access to our autobiographical memory, we would be, all the time when we dream, we would be vividly aware of the fact that, okay, now I'm having a dream. Yeah, I remember I just went went to sleep some time ago. I know where I'm sleeping. I can remember my bedroom, my bed, what happened yesterday. I know what I'm going to
00:18:55
Speaker
have to do tomorrow but let's now just stroll around in this interesting dream world for a while or fly or do whatever we like. So dreaming would lose this aspect that it its purpose is to present to us ah events and situations that we take to be really happening and this This is crucially important, especially in threat simulations, because of course nobody would like to experience nightmares and bad dreams and all kinds of horrible experiences. Many people have post-traumatic dreams and nightmares that they just hate and and they destroy their sleep and they they take them back to to traumatic experiences that they would rather like to forget.
00:19:44
Speaker
so So this is something we would not choose and the dream mechanisms don't give us that choice. They just force us to go through those simulations or we can think of them as training sessions in a way because they are functionally important. So so therefore we cannot become aware of the fact that they are just training sessions. So this is like I mean, again, taking the flight simulator analogy, if you could wipe out the memory of the pilots when they step into the flight simulator, and they would actually believe that they are they are flying a real plane while while they are there, so that they would also not only have to solve the cognitive cognitive problems that arise when when some problems arise during flight, but also the emotional responses. Oh my God, I have 300 people on board.
00:20:43
Speaker
And we have a situation here. So so if you believe that you are you are actually piloting a real plane full of people, it's a different situation than when you know, yeah, yeah I have um have a simulator training today, all day, so no stress, it's going to be fun. So so I think ah it's crucially important that we have this belief that it's really happening because then our responses, our emotional responses, our cognitive responses, our ah like choices of threat avoidance behaviors and strategies will be simulating what we would do in the real situation and and and how we should handle this when we believe that, well, maybe, I mean, i mean
00:21:39
Speaker
This is life-threatening, so you can fear for your life, and still you have to act. and that's you know It's like a very immersive experience. where You're fully immersed and in the dream, and that's ah that's a characteristic of it. You feel like this is the world when you're experiencing that world.
Theories on Dream Perception
00:22:00
Speaker
Interesting. I want to take one quick side note here before we stop talking about simulations, too, because This reminds me of another episode we did earlier on Donald Hoffman and his his ideas about perception. And I wonder if that's anything that you're familiar with or if you find any um compatibility of his ideas of ah perception as a user interface that does not reflect reality. Is that something that you're... Yeah, well, well i'm I'm not sure if I remember correctly but that
00:22:34
Speaker
he is more maybe philosophically inclined to, to go towards some some kind of almost like idealism or solipsism or something. Yeah, yeah. And that's the sort of yeah, that's the sort of tail end of it, where I think that's where he lose he loses us a little bit. But yeah, yeah. So, so I, I wouldn't go quite that far, because philosophically or metaphysically, what I still think, I mean, although experience is, yeah, I agree with that, that that we don't experience the real world. So so therefore you could call this, or in philosophy, we would call this internalism. so So we are not like in any direct connection with external physical objects, but that doesn't lead, I think,
00:23:25
Speaker
to to a sort of a denial that those physical objects still exist out there. And and that in that sense, I wouldn't go to idealism, but rather, but rather my thinking goes along the lines of what what we call scientific realism, that we still have good reasons to believe that various physical objects exist. And we try to collect converging evidence with different kinds of methods. And our physical research instruments are are in init interaction with the physical external reality. And from this data, we can infer what the physical reality is out there like, even if we can never directly see it. Because what we see and what we experience are our phenomenal experiences, which are this world simulation. So so so there is a still, ah I believe, in this sort of a correspondence between what we experience
00:24:24
Speaker
and what the physical world is like. Because again, if you take at the evolutionary argument, if evolution had come up with an internal simulation that doesn't correspond to some important aspects of the physical world, then consciousness would be not very useful in navigating our bodies through trajectories in in the physical world, because our body still is physical, and it needs to find food and it needs to escape enemies and it needs to find mates and they exist in the physical world. So so so yeah, so so i'm I'm not going that way
Consciousness: Realism vs. Simulation
00:25:05
Speaker
philosophically. I'm i'm still a scientific realist and i and therefore I still build firmly believe that the real physical world exists out there as well.
00:25:14
Speaker
Yeah, I think maybe you and Donald Hoffman have similar starting points, but end up at very different different points on the and on the yeah conclusions for that. and and I might just say, like also on the simulation side, you know that that kind of way of thinking about that our experience of the world is internalism, as you describe it.
00:25:36
Speaker
my like My interest in in visual science actually started with an experience where I had a visceral sense of that internalism, where that,
00:25:51
Speaker
you know as Newton said, like the rays themselves are not colored. right So in other words, there's nothing about a photon that is inherently red, green, or blue, but our experience of it nevertheless could represent something about the world.
00:26:08
Speaker
And I had that ah very direct experience of understanding that what I was experiencing as the world was not the world on my first trip with LSD when I was a teenager. And that visceral sense of that I'm experiencing a simulation that is both fallible and changeable led me to ah to an interest in cognitive psychology and and perception work more broadly.
00:26:38
Speaker
And I think that, you know, it's interesting as you think about different kinds of simulations. Our waking life is a simulation. Our waking experience is a simulation. And dreams are a simulation. And hallucinations are a simulation. They're different types of simulations with different characteristics. And how you view those different characteristics and what they're like, behaviorally, phenomenologically, actually can tell you something about how the brain works and how they evolve, how we evolve as a species.
00:27:07
Speaker
Yeah, exactly. And yeah, one one also or phenomena that somehow also supported this internalism was when i when I was studying neuropsychology and neuropsychological patient cases. And it was just so fascinating to read that when just often like small lesions in the brain can lead to drastic changes in in the world that the patients experience, and very often they do not realize or feel or experience that, okay, there is something wrong in my brain, but rather they experience that, why is the world so weird now? Why don't I have any color experiences in the world? like so So I was reading, like as a student, I was reading like some Oliver Sacks books, and and I found found it so fascinating, for example, that
00:28:06
Speaker
that just having having like like lesions in in your visual cortex, you might lose this color qualia. And ah just like you said, that they are not really there in the physical stimuli or in photons or any way. Nothing is painted in qualia in the physical world, but somehow the brain paints our simulate simulated world with this color qualia. And if you lose the if you have a lesion in just one hemisphere in the visual cortex, then half of your visual world might be colored and the other half is a grayscale called Hemi A chromatopsia. So I thought that, okay, so this this kind of shows that if if you would see the world half in color and half in grayscale, what you would be looking at would be a seam that is actually in your visual cortex. You would kind of see like your two hemispheres so that one of them is still able to
00:29:04
Speaker
able to color your world and the other hemisphere is not. But you, of course, feel that you are looking at the world outside and somehow one half of it loses or has no colors, the other is still normally colored. So these kinds of ah patient cases also somehow showed, I think, that that this is where we see exactly how those mechanisms in the brain work, that they construct this simulation and it comes so automatically in in the normal case in our healthy brain that we never even realize how complex the mechanisms must be that put it all together so that we have this one single unified, nice, colorful world where all the objects are nicely laid out in space. And then when you look at those neuropsychological patient cases, you realize that any of these features could drop out from my world if something pretty small goes wrong in my brain. so
00:30:04
Speaker
So yeah, so so I think this ah idea of a simulation being constructed by the brain, it's it's quite powerful. and And also I was using the the ah concept of telepresence to to talk about um perception. So that during perception, this world is actually a telepresence world so that We feel that we are present in the real physical world because the information is being modulated by online sensory stimulation. So therefore we are in a way tele-present in the real physical world. Whereas when this is cut off during dreaming, we are just present in inside this world simulation that has no current input from from the real physical world.
00:31:03
Speaker
That's so interesting. yeah and The kinds of dreams that we have and the weight and the characteristics of the dreams are informed by that aspect. right So the idea that this external stimuli are cut off. I want to make just one tiny side observation. This maybe
Analyzing Dream Content
00:31:24
Speaker
doesn't go anywhere. but It's interesting, you were talking about how one of the things that we don't see a lot in dreams is reading, writing, or working on the computer. And I've noticed that in a dream, if you try to read something, it's often very hard to actually make out what it says. I don't know if this is something that you guys have experienced or not.
00:31:47
Speaker
It's tricky because there's that reality monitoring, too. So you're not thinking you're not thinking to test it. but i mean I've definitely done this where I've tried. I mean, but not not necessarily knowing. Sometimes I know that I'm dreaming. This is like semi lucid dreaming. but But more often than not, I don't. but But I may approach something and try to read it. And again, this we get into the types of dreams that we have because I really want to talk about that because it's fascinating, the biases that we have and the kinds of things that we're dreaming about.
00:32:15
Speaker
but One of the things that I experience in dreams all the time is I'm lost and I'm late for an exam. And I'm trying to read the directions on science. And it's like, I can't read the damn sign. And this tiny observation I'm going to make is that generative AI that we have today which has the same characteristic of being cut off from continuous input from this from the sensory world, but nevertheless has that that simulation aspect and ah in a feed-forward way, also has a hard time writing things. When you make a visual picture representation in generative AI, it has a hard time correctly spelling or creating fonts. I just found that as interesting interesting. I don't know, there may or may not be any relationship there, but I just found that it's interesting, analogous situation.
00:33:03
Speaker
Yeah, what what I have or how I have thought that why why this probably is the case is that those ah cognitive skills that are not very, very frequently or, or very correctly simulated in our dreams, that they seem to be cognitive skills that require learning. So so they are not, there's an interesting difference between spoken language and written language. So so because spoken language is obviously something that that is evolutionary ancient and doesn't need to be learned by instruction, but but it is learned by just living in ah in a normal human linguistic environment. So every healthy child catches up spoken language, both understanding and and production. Whereas reading has to be forcefully learned.
00:34:00
Speaker
as well as calculation or or typing or or or these sorts of cognitive skills. So they were not present during evolution. There is no hardwired mechanism that would kind of automatically catch up with those skills. If you are not taught to do them, then you can live your whole life. And then that's i how how I guess you go to some distant hunter gatherers tribe. So so they they might not have any written language or certainly not typing, calculating or anything like that as as any any part of their cognitive machinery. so So that I believe reflects also the sort of evolutionary default settings that there are available for the simulations that are constructed during dreaming, that they reflect those kinds of ah skills and
00:34:57
Speaker
and situations that in some sense were present already during evolution. And that's why they are very hard for the simulator mechanisms too to simulate accurately. Whereas something like like you mentioned, yeah, this is a very, very typical nightmare or bad dream that you are being late from from an exam or often also like from a flight or some any important event. So this is kind of like a modern application of of this ancient being chased by a predator or or by some other violent enemy. enemy so So in our modern world, we are rarely physically chased by violent and enemies, but we are chased by the clock
00:35:55
Speaker
and we are chased by our responsibilities. And therefore, being late from some important event, it's kind of like being chased by an enemy. But but it seems to have been not too far away from these original evolutionary scripts that that it has been ah it has become one of um one of the most common ah kinds of bad dreams or recurrent dreams for adult humans living in Western societies. So you talked earlier about Hobson's initial attempts to do some content analysis on dreams and and collecting um sort of general themes that go through dreams. um Maybe you could say something about but the sorts of themes that, and you've mentioned some you're sort of talking about some of these now, being chased, running, maybe even flying or or things like that.
00:36:47
Speaker
seem to pop up regularly in dreams. And I wonder if you could talk about his research and maybe research since then that's that's clarified the sort of typical content that pops up in dreams. Okay, so when we ask questions about what kind of dream contents are typical or frequent, then we have to think about how exactly do we find out what what are the methods by which we measure dream content and what kind of samples do we collect ah that that we use then in in those measurements. So we need to define dream contents in very detailed ways so that we can actually recognize particular contents from the reports. And yeah, bizarreness is certainly one type of content, so contents
00:37:43
Speaker
and events in dreams that seem to deviate somehow from what is likely or possible during during ah waking perception. And a quick question about bizarreness too. um So with that, you we're thinking of bizarreness to the perceiver or just something that ah that statistical analysis may pull out as being unrelated to the to the world or being unreal sort of? Yeah, that's an excellent question because when we, I mean, there are certainly physically impossible events or physically highly unlikely events, which which we can recognize independently of whose dream it was. But we also realized when we were analyzing green reports that there are also also bizarre features
00:38:39
Speaker
that only the dreamer can really know whether this is unlikely to happen in their life. For example, if they don't describe who those people are that appear in their dreams, we don't know is that person somehow likely or unlikely to appear in that environment, for example. so So we also gave very detailed instructions that please explain what are the places where you are in your dream in relation to your waking life, who are the people that you encounter in in relation to your waking life, so that it it was possible to possible to know that this is this something that could happen? Or is this something that would be highly unlikely or impossible to happen someone in someone's real life? So that is certainly certainly ah quite difficult to
00:39:34
Speaker
to solve because then you need to collect a lot of extra information from each dreamer's life to know what is likely in their life in relation to like other people or the places where they spend time or things like that. But we, I think we relatively well managed to do that when we asked them to report this kind of extra information. So Bizarn is quite difficult to define somehow really, really completely objectively. Right. So if you see up if you see a purple two-headed cow in your dream, that's clearly bizarre. But if you see your uncle in the dream, that could be bizarre depending on the circumstance. Yeah, exactly. And and and also, yeah, if your uncle died 10 years ago, that would be highly bizarre. I mean, and if you don't remember
00:40:27
Speaker
in the dream that your uncle is actually dead. That is also another bizarre feature. But but if you if you see Donald Trump in your dream, then if it is my dream, it's highly unlikely. But if it is Joe Biden's nightmare, then it is highly likely actually, and and maybe not so unlikely. So so we need to know facts about the dreamer and the dreamer's life to to determine bizarreness. And there is, of course, always a margin of error. And that's why also one feature methodological feature in content analysis is, and what we always used, we used two or three independent judges to go through ah the reports and then to classify these different contents, for example, to bizarre and non-bizarre. And then we compared and we we had to get into an iterator reliability that is high enough
00:41:27
Speaker
so that we we could see that, OK, there was some kind of objective judgment done here. And it was not just somebody's opinions that we were we were calculating. and and And that's why it also has to be methodologically in a way strict, because I realized that there is a lot of not so methodologically strict ah studies in in dream research, where these sorts of biases and maybe a bit subjective aspects of the analysis can can interfere if if these sorts of like kind of standard good methodology from from elsewhere in in psychology that you should use the very same principles when you analyze ah dream reports and and dream contents.
Threats and Negativity Bias in Dreams
00:42:12
Speaker
so And how long do you think it is that we've had good methodology in, I mean, I don't know if we still do, maybe it's scattershot, I don't know. But how long do you think it's been since we've had a good idea about how to do this kind of thing? Well, there is a classical method called the Hall and One Castle method of dream content analysis. So they created a sort of a standardized way to classify many different types of dream contents.
00:42:43
Speaker
And they also used or recommended using several different judges and they published this system already in the 1960s. So basically this system has has existed, but this is a very like a theoretical system. It's purely descriptive. So we it it classifies separately like like objects and people and then has several different categories for what kind of people, familiar, stranger, and so forth, and different kinds of events and so forth. But but when you ask a more detailed theoretical question, for example, when we wanted to figure out how frequent are threatening events in dreams, there is no such category in that system that would directly correspond to
00:43:38
Speaker
what is a threatening event. I mean, there are negative emotions, but that's not exactly the same. And then we needed to we needed to figure out what is the best way to define what is a threatening event that happens in the dream. And we ended up defining it so that it is an event that if it happened in real life, there would be a risk that someone or something comes to harm.
00:44:08
Speaker
And this has nothing to do with the emotions reported. We realize that sometimes people talk about their emotions, sometimes they don't talk about their emotions, but what they always describe is what is happening in the dream world. And if we transport somehow that event and we pretend that, okay, this event is now happening in the real world, is it likely that something or someone is coming to harm because of this? Either physical harm, social harm,
00:44:37
Speaker
psychological harm. So, so that definition seemed to be quite effective, and also something that different judges could, could be ah quite consistent when when picking up threatening events, that, therefore, we got this like, iterator reliability to levels that that were acceptable that that we it's possible to extract this kind of information. And then when you define it in that way, you realize how actually frequent these threatening events are in dreams. Because these like just just like this that okay being late from an important exam. Yeah, if that happens in real life, it's quite, quite harmful for a student. Or if you if you miss miss of a flight, yeah, that's also also like, like, of course, you don't die.
00:45:37
Speaker
but you lose you might lose like thousands of dollars because your ticket is not valid anymore or or some other plans go completely completely fail. so And these might be ones that you might you might initially think of sort of a sort of anxiety dreams or you have anxiety about something, but that that would fit within the idea of a threat. Yeah, that that that's right. But but yeah, we we initially we also tried to define threatening events via the emotional words like anxieties and fears and so forth. But then we realized that actually this is what people are not consistent in describing. So it's much easier to judge whether an event would be harmful if it happens in real life than to judge, okay, was the dreamer anxious here? Was the dreamer afraid here? Sometimes they don't they don't talk about their emotions at all. They just describe some
00:46:36
Speaker
Or they might even say that, that yeah, that i I could see that some horrible, I don't know, tsunami was approaching, or that there was a, I heard that there's a World War III has broken out, but I wasn't afraid in the dream. So people might even even report that even though something very dangerous was happening, that they didn't feel the fear, but that would still be a threatening event in in this more objective way of defining it. and And that's why we started to use this kind of kind of definition.
00:47:18
Speaker
And there is maybe a sort of a misunderstanding often when I talk about threat simulation theory, then people often interpret that what do we mean by threat means something that you emotionally feel as a threat. But that's not actually the case when you when you look at how we have defined it in our like this content analysis method, when we pick out threatening events from dreams, they are these objective situations that might, in the real world, harm someone or something. Yeah, I think that's so that's such an interesting distinction, actually, Rolf and Auntie, like that that notion, like and i because i certainly that's what I've always thought of it as being, in my own experience, is like an anxiety.
00:48:04
Speaker
response, an anxiety dream, but actually there's something very elegant about the approach that you've taken andie a about you know threat simulation, social simulation. What are the most important things evolutionarily for the human being? And if we're using our dreams as a simulation place to work these things out and get better at and improve on doesn't necessarily need to be anxiety producing in the sense that where anxiety is an overreaction or a negative feeling about a stress response. where you know Whereas sometimes you can be in a very threatening situation in real life and respond in a way that isn't anxiety you know producing, but it's rather
00:48:53
Speaker
stimulating, but that stimulation is appropriate to to the response. And you might have those similar kind of responses in a dream as well. And so if you then flip it on it on its side and say, well, what does the content of dreams tell us about what is important for people and what has been important for our ancestors, then it gets really, really interesting. If you then take the theory as a given and you think about, well, what does it say about what's what's important for us?
00:49:22
Speaker
And I think yeah maybe with that in mind, you want to say a bit more about like what what are what are the kinds of things that are overrepresented in dreams that you've seen through your content analysis? And what do you think that means about dreams and and about people? Yeah, right. So so ah yeah, we have been paying attention to this. And I think this is another maybe sort of characteristic of of my approach to to the testing theories of dreaming that that the argument is that we really need to look at the statistical properties of large samples of dreams which are systematically analyzed by their content. that because And this connects kind of to the evolutionary thinking that natural selection works on statistical probabilities. That what is selected for is something that gives you a statistical benefit
00:50:23
Speaker
without incurring lots of costs. So it's a kind of a cost-benefit statistical calculation. I mean, of course, not an explicit calculation, but this is so this is how it works, that those things that are useful, they they are propagated further. And therefore, therefore I have ah paid attention to these kinds of things that are statistically overrepresented in dreams or all that other kinds of biases that there are.
00:50:53
Speaker
in dreams. And therefore, in threat simulation theory, developing the theory and testing the theory, what started to occur to me is that there are very conspicuous features in statistical features of dreaming that I have been calling the negativity bias of dreams, that it comes up in many, many different contents of dreaming. It does come out also in emotional content. So that when I was reading like old, these kinds of old ah studies where we're just descriptive about what we have found in normative studies of emotional contents, mostly based on emotion, words in dream reports, that negative emotions were like
00:51:45
Speaker
80% of the emotion words and positive emotions were 20%. So that was like a really conspicuous difference in those classical normative studies. Then there was a category called misfortunes versus good fortunes. Misfortunes were many times over more probable. And aggression was more probable than friendliness and so forth. So so I kind of but realized that okay there seems to be an underlying pattern here, which emphasizes negative events. And and then, of course, this led me to the the concept of threatening events, that that they are all ah expressions of something dangerous happening in the dreams.
00:52:38
Speaker
And therefore we need this concept of threatening event. Like like I just explained that that it needs to be separately defined so that so that it actually catches exactly those kinds of events that we want to quantify from dream reports. That we can we can test the theory end and we can show that threatening events are actually overrepresented in dream life as compared to waking life. So so we ran one study where we had the same subjects write down their dreams every morning as, I mean, we we give the standard instructions that that they should write down everything that they remember. We never tell them that we are necessarily studying threatening events, but but just give a sort of a general instructions how to remember your dreams as as well as possible. And then they were writing down every evening sort of a diary
00:53:38
Speaker
about the major events that happened during the day. And then we content analyzed both types of reports. And it turned out that there are many more threatening events happening in our dream life. And they are more severe than the threatening events happening in in in waking life during the same period of time. So so this shows that Dreaming, dream world is much a much more dangerous place, so to speak, than our waking world. Now, are there individual differences across this this kind of thing, culturally or disposition wise or anything like that? Or is it does it feel like a universal feature that dreams are have this quality? Yeah, there are some individual differences. But again, if we look at the big picture,
00:54:36
Speaker
and And there have been already many samples from different countries. Like, of course, I started in Finland. We have some samples from Sweden. There have been different groups in Canada, in Germany, studying, I mean, using our threat and analysis scale. And it's quite consistent that in adult dreams you find in 60 to 75 percent of dream reports, there is at least one threatening event in the dreams. The threats are typically targeted at the dream self or to close people, but most often at the dream self. So it's different from watching horror movies where you see some strangers being threatened by by some horrible events or enemies in the dream.
00:55:34
Speaker
in In our dreams, it is we ourselves and our close ones who are being threatened. So it's not like watching a horror movie. Even if you take something from the horror movie, it will be incorporated into your own life, into the context of your own life. And they are after you and not after the actors when you have have the dream. so So it is in that sense so kind of very self-centered, which of course makes sense from the perspective of training a training function.
00:56:09
Speaker
ah And this over representation, then it comes also when we yeah, we can do like two kinds of comparisons, we can compare negative, similar negative events, and positive events in the dream world, like emotions. And we can see that negative emotions are more common than positive emotions in many samples and and reported studies. And then we can do this comparison between negative events in the dream world versus negative similar negative events in in the waking world. And there we also see that the dream world is more negatively biased. So so therefore, I think this negativity bias has been quite well empirically
00:57:03
Speaker
established that this seems to be a very like universal ah statistical bias in dreams. And it is quite rare to find that in in the samples that we have had that there would be a participant who reports, let's say 10 dream reports or 20 dream reports, and there wouldn't be any threatening events in any of those.
00:57:32
Speaker
dream reports. I don't remember we ever had such subjects who wouldn't seem to have anything. But there are still of course individual differences so that some people have lots of like nightmarish dreams and others have more mundane dreams with not that many. And also this has to do with the idea that that is part of the theory that this threat simulation system as we call it that it can it can be like in different activity levels and it is sensitive to external cues so that if you are experiencing a lot of dangers or stress or or some kind of negativity in your waking life that
00:58:28
Speaker
that kind of activates the feeling of being threatened in your waking life, then this will usually increase the activity level of your threat simulation system. And the most blatant examples are people who have post-traumatic dreams or who are living in a war zone or who are otherwise living in environments which are full of danger. So so their threat simulation system seems to be at a much higher level of activity than someone living in a completely like safe environment and and and without any stress and so forth. So one question I would have too is, um, is there a way to, to tease out the utility of having this negativity bias? Um, you know, by reducing, I don't know, reducing REM sleep or X, you know, one,
00:59:24
Speaker
One potential way is with Pilarancico's research suggesting that you have less negativity bias when you're dreaming under anesthesia. um Would you predict that if you if you did all your dreaming under anesthesia, reduced the amount of negativity bias that you had? Would that have a detrimental impact on your and your life? Yeah, it's difficult to say.
00:59:52
Speaker
It's difficult to say well what to predict of dreaming under anesthesia because I mean, well, yeah, we we do know now that during anesthesia, at least the relatively light sedation, which still makes you unresponsive, but it's not necessarily at the level of surgical anesthesia, that many people do report dreamlike experiences and that there are some anesthetic drugs like dexmedetomidine, that seems to be somehow inducing a similar state, like maybe like non-REM sleep. But we don't know the exact like neurochemical differences, so it's very difficult to say what we should predict happening to the threat simulation mechanism, ah that should it be activated or not, so so I don't
01:00:50
Speaker
know how this actually relates to the theory? Or does it test the theory? Because of course, being under the influence of anesthetic drugs is in no way something that evolution could have. could have yeah you need um ah you You might need something better if there was some way to just magically reduce the negativity bias without affecting anything. There is actually Actually, lucid dreaming, I noticed a study that was a content analysis of lucid dreams. So lucid dreaming is is exactly the kind of dreaming where you know that you are dreaming. So that in that sense, you have already already been able to cancel one of these central ah features of these simulations or the simulator
01:01:41
Speaker
ah that tries to make us believe that the simulation is happening for real. So lucid dreaming which is quite difficult to achieve and quite difficult to keep up. But of course there are people who have spontaneous lucid dreams and then there are people who who train in having more lucid dreams because it's it's quite an interesting state also to have. So they analyzed dream reports of lucid dreams and compared them with dream reports from non lucid dreams. And what was interesting was that lucid dreams have less dream characters or less other people present in the dreams. And they have less negativity or or more positivity in the dreams. And when I was thinking about this result, then I thought, oh, well, this makes kind of perfect sense that lucid dreaming seems to cancel out both
01:02:40
Speaker
the threat simulation function and the social simulation function, so that when people get to choose what they actually want to do in in inside this simulator, when they have full access to their like a voluntary choices and and and rational thinking, then they choose to do things that are, of course, that are not frightening or negative And they also have less social interaction and social cognition involved. That is fascinating. and so So that was interesting. out This article didn't, of course, I mean, it was purely descriptive.
01:03:25
Speaker
so
01:03:27
Speaker
but But now when I when i realized these results, I think this very nicely fits together with with the pattern of ah threat simulation theory and social simulation theory and why they are not why Why lucidity is not really something that we have regularly. Yeah. And thinking, a ah you know, drill drilling down a little bit more on this, on the on the bias and its purpose, is there evidence that you can point to that as a species or as individuals, this simulation has made us better at
Functional Benefits of Dreams
01:04:03
Speaker
something? Like in other words, is there so any way that we can show that this like flight simulator for
01:04:09
Speaker
are threats actually make us more effectively responsive to those threats? Yeah, well, this is maybe the most difficult part of of the theory testing to actually so show ah like behavioral effects. And the argument has been mostly like indirect, that basically we know that training something makes you better and repetitive training makes you makes you like even better and and that there is something like implicit learning that we don't need to remember or recall explicitly the training sessions. But if we have been going through something repeatedly, like in this case, threat to recognition, so that you notice something, there is some kind of enemy or some other risk developing in the dream, and then choosing an appropriate
01:05:07
Speaker
behavioral tactic to to avoid the threat, that you are doing these sorts of things repeatedly. So this, I mean, plausibly could lead to to some effects. There is one interesting study that was in a way trying to figure out how to measure this. And then they collected dream reports from students who were going to participate a highly demanding entrance exam to the best medical school in in France. And then they looked at the dream reports and many have had had ah anxiety or or nightmares dreams about the entrance exam and what could go wrong with the exam. So these kinds of typical like yeah being late or or somehow forgetting to prepare for it or or
01:06:04
Speaker
or missing a ah bus when they were on on the way or all sorts of things that could go wrong. And those who reported these kinds of like threat simulation dreams about the exam going wrong, they actually got better results in the exam itself. So so that that was a very nice way to kind of try to measure something quantitative. A quantitative performance is that is read directly related to the kind of very specific threat simulation dream and that the situation was genuinely stressful because it basically determines the whole life of of the student student that that if they get in or if they don't get in. So so they were under very high pressure in participating in that that exam. ah But of course, this is not
01:07:02
Speaker
a very evolutionary scenario at all. so so So it doesn't show these sorts of things like, okay, so if you were dreaming of predators in the savannah and detecting them, so did you get better at detecting them visually? Did you get faster at deciding what is the correct threat avoidance strategy? Is it to escape? Is it to hide? Is it to scream for help?
01:07:31
Speaker
or something else. so so
01:07:36
Speaker
but i mean this yeah yeah like This sort of speaks to our stress management system in general, right? That nope we often think of stress as a bad thing, but of course stress at appropriate levels is a good, useful thing to have. It gets us motivated and and concerned about the the right sorts of things. but it's also you know you You think about it from a stress perspective,
01:08:01
Speaker
activation, but also you know error correction. and So it's like if you're responding to errors that you've been making in your simulation, trying to correct those errors through repetitive you know action, trying to you're basically trying to reduce the loss function of the difference between your simulation and the real world right in some way to improve your performance. Right. and and and And in this case, we don't also really know whether this effect was somehow mediated actually via explicit memory of those dreams. So that if you were dreaming that, okay, I forgot to take take my my pen or my books or my notes or whatever into the exam, or I forgot to check the the train schedule or or something else that might have gone wrong. But when you wake up from this dream, you're like, oh my God, this is something I need to check immediately. That at least I won't make that mistake that I ended up doing.
01:08:59
Speaker
in the in the in the dream. so So that would be, of course, possible, but but the theory says that because the simulation functions must have been effective in ah animals and in ancestral humans who didn't, I mean, write down their dreams or or or even maybe have any spoken language to communicate their dreams to to others. So so So the rehearsal functions have to have the behavioral effects or the cognitive effects without the ability to actually recall explicitly the dreams. But it might be, of course, an additional boost still to the function if you do recall them explicitly. And then you can explicitly also ah avoid some very specific kind of scenario that was shown to you.
01:09:57
Speaker
in the dream. Yeah. I mean, one one you know's there's a connection point here, too, between you know one type of dream that is overrepresented, which are these threatening situations, and the social situations, which are the site you know like second group of overrepresented types of dreams, which are social in nature.
Social Dimensions and Animal Dreaming
01:10:17
Speaker
I think that these are probably not like mutually exclusive you know ah categories, but actually probably quite closely related when it comes right down to it.
01:10:27
Speaker
aspect of our ancestors survival as a social species was that interbeing, that interrelation between members of the tribe and and the greater community. So things that are threatening to your social standing, to your position within the group are especially threatening to your livelihood, to your life. So I think those are yeah interesting connection there. But I would just have to ask like,
01:10:56
Speaker
Why is it then that like the one of the most common dreams that feels threatening socially is that like you're not wearing pants?
01:11:07
Speaker
you're not worry like this This is such a common thing. It's more about embarrassment in some way. right like You're trying to avoid embarrassment and and the role of embarrassment and so the importance of that in your social relations and big being not excluded in some way.
01:11:26
Speaker
Yeah, yeah. And and definitely you are right there that that we need to consider that all kinds of threats to to your social status and your social relationships, they are and and where also during evolution, they were like, like very serious threats to your well being. And therefore, they also need to be simulated. ah Why this particular kind of threat is so common and and and one of the sort of typical negative dreams, maybe also universal dreams. Yeah, certainly there is this threat to your yeah being embarrassed in front of of your peers or or other, just other people. So it certainly threatens your social ah status. So in that sense, it could be just like a general social anxiety dream.
01:12:24
Speaker
I have been also, well, this is pure speculation, of course, that why is it that we are naked or we are somehow in ah inappropriately clothed? That could this also be some sort of evolutionary remnant that, I mean, ancestral humans were not worried about their clothing very much. So so basically basically, maybe there there still are sort of sort of ancient scripts in in in memory that when we go about in in the dream world, we don't actually usually pay attention to ourselves or our bodies almost at all. This was one result we also got got in in in this in this study that we looked at dream contents and bizarreness. And we just found out that the cell the dream self is always almost always present in the dream,
01:13:22
Speaker
is the central character and actor in the dream, but it is present only as a first-person perspective. ah tests i mean it has The dream self has a body, it is an embodied being, but there is usually nothing reported about the bodily aspects of the dream self, except actions. I was walking, I was running, I was talking to my friends,
01:13:50
Speaker
and and so forth. So it's more like the location and the perspective and the actions, but not the dream self's body itself. so So therefore it may be that the the dream self and and and its embodiment, they are mostly kind of implicitly only present or in the background of your conscious experience. And then if you pay attention to your body, maybe then these sorts of I don't know, ancient, ancient scripts are actually not so uncommon that you suddenly notice that you don't have appropriate clothes or that you are naked. And then this becomes a show social threat. But this is, of course, just speculation. But what is what has been shown is that the self, we don't look at ourselves in dreams or evaluate our bodies in dreams. We are focused on the dream world and what is most often
01:14:51
Speaker
talked about in dream reports are features of the external perceptual dream world. it's It's objects, it's locations, other people and the actions and social interactions that are going on there. So this is this is what dreams are mostly about. It's not about our own appearance. I mean, as we think about dreams as simulations and then our waking life, our waking conscious experience about as like a simulation. I don't know, maybe it would be interesting to go down that route a bit to talk about consciousness and, you know, the the little hook that I might use is, you know, we were talking about dreams and other mammals. So how do we know that other mammals have dreams? You know, which of course,
01:15:51
Speaker
You can imagine where this will lead, but ah do you have thoughts on that? I mean, i you know I look at my dog and I see having little pups, what we always call our puppy dreams, and she where're you she's either playing, fighting, or hunting, something. It looks like, I mean, for all the world, it looks like she's dreaming, right? But how do we know? like how How could we know that another mammal is dreaming or not dreaming? Yeah, right, right. I think exactly what your observation is is exactly one one line of evidence that we have, but but it has been also studied like more systematically. And there's an interesting phenomenon that we know from human dreaming or rather sleep disorders, which is called REM sleep behavior disorder. And this is a disorder that ah cancels out the muscular atonia that is normally on during REM sleep. so so
01:16:50
Speaker
One of the hallmarks of REM sleep is that we have practically no muscle tone, that all the muscles are totally relaxed and actually totally paralyzed. You can experience this if you have ever experienced the so-called sleep paralysis, which means that you wake up from REM sleep, but the muscular atto i mean this mechanism that turns muscular atonia on, then it's still on, and you realize that Oh my God, I can't move. I can't properly wake up. I can't even open my eyes. What's going on? Am I dead? so So this is a very efficient mechanism. But if it is broken, then these people who have REM sleep behavior disorder, they actually start to act out the actions that they carry out during their REM dreams.
01:17:49
Speaker
And these actions, I mean, we we have quite a lot of data about these already and descriptions in the, mostly in the like medical ah literature on sleep disorders, that that we know that these actions are most to commonly expressed in kind of nightmares, very powerful, intense dreams.
01:18:17
Speaker
so that we can observe how the dreamers, they they they can like shout something, they can throw punches around, they can kick, they can they can jump out from their beds and start to run. But then they collide with with the furniture and and they can even break their bones. And this is not sleepwalking. Sleepwalking is ah an entirely different phenomenon. Because in REM sleep behavior disorder,
01:18:47
Speaker
the dreamer's consciousness is entirely immersed into the dream world and the actions reflect interactions with with with that that environment and and what's going on there. Whereas sleepwalkers typically have their eyes open, they are in non-REM sleep and they are in a kind of a mixture of wakefulness and sleep so that they can navigate in the real world with eyes open but they just have some some weird idea in mind that they need to do something, some kind of motivation or about something, which can also be a sort of a threat that there is a burglar or maybe I forgot to to do to check some window or whatever. So but but that sleepwalking is very different. So REM sleep behavior disorder shows us that there are complex behaviors that express navigation in the dream world according
01:19:45
Speaker
to the stimuli that are present only in the dreamer's consciousness. And now the kind of actions that that you were describing that we can we can see in in dogs when they are in REM sleep, and cats as well. ah They have been more formally studied so that the first studies were already carried out, I think, in the 60s or 70s, where cats were artificially their REM sleep atonia was removed so they were basically artificially having their REM sleep behavior disorder and they started to act out what must have been their dream experiences and they were interacting with seemingly other cats so that that they seemed to like do sort of aggressive
01:20:41
Speaker
behaviors towards some other cat. so So we can observe the same phenomenon or the same disorder both in humans and in other mammals. And it can be caused by experimental lesions. So this has been done especially with cats so that we can observe ah the cats standing up and and starting to express different kinds of behaviors which seem to be very cat-like rehearsals of seeing other cats and behaving aggressively towards them or trying to catch a mouse or pawing at some kind of small prey and and other types of behaviors that I would imagine make sense for a cat to rehearse in a simulation. And in dogs, there are, yeah, I actually have seen some video clips
01:21:42
Speaker
in YouTube about dogs that obviously seem to have this REM sleep behavior disorder that they actually do very violent like running and and other acting out that that seems to be the acting out of of dream experiences. So I think it would be very difficult to explain these behaviors if we don't assume that the animals are actually expressing interactions with their dream worlds, ah just like human patients do. And in human patients, we can collect the dream reports and we can see that there is a sort of an isomorphic match between what they reported dreaming about and what what we could objectively observe concerning their
01:22:36
Speaker
actions during when when their brain was still under REM sleep. So I think that is a very, very convincing piece of evidence that other mammals also do dream and that what they dream about are very like species specific events sort of that that makes sense that okay, so evolutionarily, it was functional for them to undergo such behaviors and such events in their dreams, that that these are the kinds of skills that they require in in their everyday waking lives.
Future of Dream Research
01:23:17
Speaker
so i notice I notice as you're saying that you're avoiding saying threats when you're talking about other mammals too and I don't know if that's intentional or not but I'm wondering I mean just sort of intuitively when I think about it when I watch my cat you know in what seems like it you know it's maybe chasing a mouse or something like that as as it's dreaming um it doesn't I guess i I wonder if there's a ah fundamental difference between predator and prey and something like this, where you know prey would be more concerned about threats and predators would be, I guess it would be strange to call it threat simulation theory, but like you say, that they're practicing relevant things for their ecological needs. Yeah, exactly. Exactly. i I think we need to do a sort of a similar kind of evolutionary analysis, just like like that
01:24:07
Speaker
we are we can be pretty certain that ancestral humans for for their survival, ah various kinds of environmental and also social threats were highly important. Therefore, also their dream simulation should should ah be mostly focusing on those kinds of events. But now, yeah, if if you If you are a predator at the really top of the food chain, like I don't think lions need to do a lot of threat simulation in in in the in the way that someone is chasing them, maybe other other lions. I mean, of course, they they still have like interspecies aggressive encounters with other lions and they fight fight for mates and food and things like that. So that would still be
01:25:05
Speaker
you could say some kind of threat simulation, but I would imagine that, that yeah, that they would probably simulate like like how to catch prey and maybe also sort of social simulations because they do this in interaction with with the whole pack of lions. So so i could I could imagine that their dreams are about how to how to guide and encircle this this ah group of prey and then which one to select to attack from them. So that would make much more sense to them. And yeah, in a sense, that's not a threat simulation. it's It's a simulation of skills which are are like so necessary and and highly important for for their own survival. And that's what that's what they need. If they are unable to catch prey, then
01:26:04
Speaker
they They won't survive for for long. so I don't think we have any data on lions and dreams, but but if ever a we we get something, I could issue some predictions what they would probably be like. Well, that might be a ah great place to ah start to wrap it up.
01:26:27
Speaker
It's a fascinating conversation about this and we could talk for another hour and a half easily and probably more just about the dreams. But, you know, we'd love to have you on again. Sometimes talk more about that and and other things as well.
01:26:43
Speaker
But where we like to wrap things up is, what is something or some things on the research side that you're particularly excited about going forward? What are you excited, whether it's something that you're working on or something in the field that you think is a really exciting next step or extension?
01:27:04
Speaker
Right. So so yeah we have mostly been talking about the threat simulation theory. And and that theory has already been tested quite a lot. So we do have quite quite many different studies that support or give quite nice support to that. But then this other theory, social simulation theory, which is more recent, I would like to see more detailed tests of various predictions of that theory as well, because now it looks like the the general idea that
01:27:43
Speaker
dreams have this sociality bias or that dreams also depict social situations and social interaction more frequently than our waking life does, so that we are very rarely alone in our dreams. But in waking life, we I mean, it's not that uncommon to spend time alone, especially if you are working or if you're just chilling somewhere, so So, but we don't actually dream about those things. So so we now know that that dreams bias social situation, social interactions as well. But what would be the more detailed social functions or social cognitions that we rehearse during dreaming? I would like to test
01:28:42
Speaker
something around those issues. We have tried to test some of the ideas. For example, is there a difference between how much we dream about familiar people and are we trying to strengthen our bonds with them? Or do we, why do we dream also quite much about strangers? Is there a function of figuring out about strangers? Are we supposed to be friendly towards them or are they some kind of enemies?
01:29:13
Speaker
ah Then there what there is evidence for is that we actually do quite a lot of mind reading in our dreams so that in many dreams which are social we try to figure out what the other other dream characters what are they thinking or what other intentions and and and and that's quite interesting because mind reading and and this theory of mind abilities they are like highly specific to the human species. So could that be something that our dream simulations have also picked up as a very important skill? And relating to that, what we also have find in our studies on bizarreness is that one of the most common types of bizarreness is that these other people, even if they are familiar from waking life, their actions are often bizarre or unexpected or unpredictable. So
01:30:11
Speaker
This seems to suggest that maybe one of the functions is that ah dreaming throws us in kind of unpredictable, unexpected social situations. And then we have to use this theory of mind to try to figure out, so, okay, what what's going on here? Why is this person suddenly aggressive towards me? Or why is this person doing this or saying that? So, so I would really like to,
01:30:39
Speaker
go deeper into the social simulation theory and can we make it equally convincing as the threat simulation theory? So that's certainly one issue. ah It would be very interesting to have data from different age groups as well, because we could also predict that in different age groups, there are different social functions and social interactions which are most important.
01:31:09
Speaker
And one of which we can say there is maybe some kind of anecdotal evidence, but I haven't seen any good, like like proper study that would actually test the theory. ah Is it possible that these social simulations might have some kind of mate selection function in adolescence? Because one of the most
01:31:37
Speaker
repetitive dreams seems to be also that we dream a lot about the social group and and the people that were our friends and classmates, let's say in high school, like in teenage years. Those people stay for a very long time in our dreams and often they are our best friends and our crushes and and also like our romantic interests. So is there something like like ah A simulation is sort of trying to sort out what would who would be the most desirable mate and then presenting romantic dreams maybe about about ah people who who we... and And in this case, there would not be threat threat simulations at all, but actually positive dreams about about the people that we should bond more closely with. so
01:32:34
Speaker
So these kinds of hypotheses would be very interesting to test. Another thing I have been also thinking about, and sometimes we already planned to do something about it, but haven't done yet, is how do digital media and devices, especially like like smartphones, that we use them so much now and all kinds of screens do they come into our dreams or not? Because even social interaction, I mean, right now we are talking to our screens, but but still in a way it feels like, okay, so I'm somehow present in the same space with with you guys. and And now also this is just like sort of anecdotal evidence that even if we are in interaction
01:33:28
Speaker
with people virtually and digitally and via screens, it seems that in our dreams, the social simulations present those people as present within the same space. I mean, in real life, i'm not real life, in this same simulated space, so that in in the dream, the you guys would be in my dream, like here, in my house, or I would be maybe at your place,
01:33:57
Speaker
And we wouldn't have a dream where we talk to a screen. so So is this also a sort of a reflection of the kind of evolutionary biases that if you dream about specific people, they are present with you in the same space and and not via some digital media. So so that would be a fascinating topic as well to see how far do let's say smartphones or other screens enter and and be incorporated into our dreams and in what ways? Or is there a same sort of effect? Like we talked about that written language and typing and calculation doesn't really get to into our dreams because they were not present during evolution and it's somehow a very unnatural content to be simulated. So is is it the same with screens that that that they they won't be simulated or they are simulated only
01:34:57
Speaker
in that kind of threat simulations where you take your device and then suddenly it crashes or it it doesn't work properly, you scroll and there are some very strange things going on. And I mean, this has happened in in in my dreams so a lot when i I'm supposed to giving a ah lecture in my dream. And then when I look into my laptop, I can't, I mean, it's really weird stuff on the screen and the audience is waiting for me to already start talking and i'm I'm just sweating there and trying to figure out do I need to need to like like reboot my computer. I have even pressed control alt del buttons in my dreams when I have tried to try to ah reboot my laptop to to start start it again because nothing is working when I'm supposed to have a slideshow going on. I've had so i have had similar kinds of
01:35:53
Speaker
Lecture anxiety dreams must be pretty common. Exactly. So we should run a study about lecturers and professors, ah threat simulation dreams. So so that that seems to be probably something that that is quite common. Well, this say there are so many interesting open questions left here, and um i that's why i it makes such a fascinating topic to to learn about and to keep updated on.
01:36:21
Speaker
So Ante, thank you so much for joining us. And we really love talking to you. Thanks for having me. And yeah, I'd be happy to continue any time. But yeah, I really enjoyed talking to you. So thank you very much for having me.