Why and How Do We Dream?

Dreams are so subjective and fleeting that they might not be possible to study directly. laboratories around the world have developed ways to get into the minds of people while they are dreaming They are learning more about why we need these strange experiences and how our brains make them. Steven Strogatz talks with Antonio Zadra of the University of Montreal about how new methods have changed our understanding of dreams.

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Transcript

Steven Strogatz is the host of The Joy of Why, a show that explores some of the biggest unanswered questions in math and science.

We are going to talk about dreams. Exactly what are dreams? What do they do? They are often so strange. We all have had the experience of dreaming about a crazy story with people we don't know in places we don't know before. The brain is trying to make sense of something. Is it evolutionary to dream? It's difficult to study dreams. We don't have a way to record what someone else is dreaming about. It is easy to forget our dreams if we do not write them down. Dream researchers are making progress in figuring out how we dream and why we dream.

Dr. Antonio Zadra is a professor at the University of Montreal and a researcher at the center for advanced research in sleep medicine. He studies nightmares, recurrent dreams and dreams of the unconscious. When Brains Dream explores the science and mystery of sleep. Thank you Tony for joining us.

Antonio Zadra would like to say thank you for having him.

Strogatz is excited to speak to you about this. As you and your colleagues see it today, the science of dreams is not new. It's hard to study dreams.

One of the biggest challenges in studying dreams is that we don't directly look at them. People tell us what they dream about or what they write down. After the fact, most of the work is finished. When dreams are studied in the lab, you can see what is happening in the brain and body, but you can only see what the person is dreaming about when they wake up. Dreams are not public.

The challenges in studying dreams aren't unique to dreams They are found in many other places. In the study of pain, you can't have a machine that lets you see the pain. It's inferred from the way people describe their pain. Is it a burning pain or a throbbing pain? Where do they say that it is local? People say it's in their legs. These are not public experiences. Human beings have a lot of subjective states.

It wasn't until I thought of it like that that I realized it was an interesting analogy. I would like to ask you to define dreams. In any scientific field, giving a definition is very common. Let's attempt. There is a question about what a dream is. What are the things that make up a dream?

There is no universally agreed definition of a dream. For some researchers, dreams are elaborative, narratively driven creations of the brain, that are located somewhere, that have temporal dimensions, that involve emotions. These are more similar to the dreams people will recall when they wake up in the morning. For other researchers, dreaming refers to any form of thinking that occurs during sleep. This is called sleep mentation.

Depending on how you define them, dreams can be isolated images or thoughts. Geometric images can dance before your eyes as you sleep. They can be rich and narratively driven. Depending on how you define them, you might be studying various elements or different forms of dreams. If we asked how do you define consciousness, it would be the same question. Is consciousness what it is? There are very little forms of consciousness, like when you wake up in the morning, or in the midst of a terrible fight with your spouse, or in the midst of a movie. These are different types of consciousness. There are people who are blind or deafness, and they have consciousness as well. The range of their subjective experiences varies a lot. The same holds true for dreams.

Strogatz asked if we knew how our brains created the images associated with dreams.

Zadra says the short answer is no. It's because dreams can occur across different stages of sleep, and that what brain areas are activated varies a lot. The brain's general chemistry leads to different views.

We know that the secondary visual areas are activated if we take the most vivid dreams. Dreams are very visual. The primary visual areas aren't activated because your eyes aren't open. Your brain is making something. The part of your brain that controls movement is activated. One of the things that helps give us the impression that we are in a real world is that. The limbic system and the amygdala help explain why many dreams have different degrees of emotions. The part of your brain that is above your eyes is called the prefrontal cortex. Executive functions, judgment, critical thinking, planning, things that are usually absent in our dreams are important for these areas of the brain.

We are starting to understand how different brain areas work together to create our dreams. What is more of a mystery is how the brain chooses the right images. Why.

Strogatz asked about the aspect of dreams and memories that have to do with waking life. It has been suggested that dreams could help us remember. I don't know what the correct statement is. What are we thinking today?

Zadra said that sleep plays an important role in different forms of memory. Different stages of sleep help consolidate our memories. You want to remember facts if you learn them. Our memories are more related to our knowledge of the world in REM sleep. It is more about when and how you use the facts. Non-REM sleep is more important thanREM sleep to make you smart. REM sleep can allow you to be a little bit smarter.

Dreams may play a part in some of the processes. Dreams are not random, unlike some of the conceptualizations of dreams from the twenties and thir seventies. Our brains show a preference for emotional experiences from our waking life. It takes that experience and searches through all of its memory banks for weakly associated experiences that are related to it.

Why would it do that. That is how the brain works to understand the world. The brain needs to shut off all external input for an hour if it wants to make sense of what has happened. That is one of the things that sleep is about. One idea is that dreams can play a part in this. Is this useful in the future? It is said that memory is not about the past. The future is the subject of memory. When you are retired and having a drink with an old friend on your porch, it is not the reason you can remember things. We have capacities for memory, not because of that.

When you look in your rear-view mirror and see the flashing blue and red lights, you have the ability to remember. Predicting and understanding what unfolds before you and making the correct interpretations of the world around you is what it is.

Dreams take in what we experience. It is most likely due to the chemistry of the brain when it is asleep. Weak associations of this are sought out. Your brain is opening drawers and asking if it fits with this. Is it compatible with this? Your dreaming brain uses the information you give it to say, "Yes, this is a useful connection." This is a possibility. Our understanding of the world is helped by this. When we wake up, we have a better idea of ourselves and the world around us.

The brain does two amazing things when we dream, and people often take for granted the fact that the brain does that. It does a lot of great things. It creates you. You have a body, you see things, and you have a dream. Everyone you meet is included in your dream environment. You have to remember that you are in your bed sleeping. You're not hearing things from the outside world, you're not seeing things, but you're hearing them speak back. You don't know what will happen in a dream if you don't know what will happen in your dream. Your brain is telling you what's going on. In a dream, you can make a dream character appear, but if you ask them a question, you're done. In my dream, what are you doing? You don't know what the character is going to say. Your mind does. This character is created by your brain.

When people say, "Oh, you can do anything in your dream," or "You are the main actor of your dreams," I don't think that's right. Your brain is in charge of dream construction. Your brain keeps a lot of information away from you. What's the reason? In times of place and locations, dreams have all kinds of shifts in their structures, so it needs to know how you are going to react to this ever evolving narrative. Their strangeness is part of it.

This is a reflection of your brain's weak associations. How do you react to that? Dreams are a part of our understanding of the world. Our understanding of the world is dependent on what we remember. What is it about these events that makes us feel that way? A lot of this is based on what's said. The word "accident" has many meanings and associations for us. It's the same thing for objects. Glass and wine. There are different meanings to all of them. There is no glass in front of you when you dream of a glass. There are many metaphors and associations to that object. As dreams unfold, all these associations become even more complex.

You have gone in many different directions there. The one that is really hitting me is the one that uses phrases like "your brain is keeping certain things from you." I wonder who the person is in that sentence. Most people think of their brain as their own, but there is more to it.

Zadra is absolutely right. Some people think that the same can be said for waking consciousness. That is questionable. When it comes to dreams, this form of altered consciousness is less controversial.

I can give you two examples of how your brain uses your thoughts and reactions to evolve your dream. People have flying dreams sometimes. This is wonderful because they are soaring through the air and looking down at the landscape. They think about how I am flying. They fall to the ground as soon as that question appears. There is a constant interplay between what the brain is putting you in and what you think about it.

One of the functions of dreams is that. There are a lot of things we don't have to experience for sleep to be effective. It can regulate a lot of things. Without a conscious experience, all of that is accomplished. Why do we have to experience dreams in order to process memories?

The brain needs to dream in order to make sense of the world. It needs to understand how you react to the dream it's constructing, and how the dream environment which again, because it's created from your brain, is your conception of the world. What do you think happens when you dream? The interplay between you and the dream world is useful for your brain to make sense of. The "you" in the dream is just a small portion of what your brain is doing. I think there is compelling evidence that your dreaming brain keeps a lot of information hidden from you if you want to.

Strogatz is good It is time to go to dreamland. Several directions came from what you said a few minutes ago. It would be a dream. You mentioned something about the neuroscience of dreaming, and how it ties into strange associations and things like that. I would like to do that as well. Why don't we start with dream engineering? Tell us what it is for people who haven't heard of it before.

A lucid dream is one in which the person becomes aware that he or she is dreaming while still in the dream Once people have this awareness, they can use it to manipulate or influence their dreams. That's what a dream is. There are many interesting features of the dream. It opens up a new window into the study of dreams in the sleep lab.

Is it something that people do naturally, or do you have to learn how to do it?

Some people have had dreams all their life. As far back as they recall. A small percentage of the general population are minorities. When they learned that not everyone has this ability, they were surprised. Half of the population will have had at least one dream in their life. About 20% of people have at least one dream a month.

There are people who have dreams almost every night. You can look at them in the lab. When I say that it opens up a whole new window and that it has been done in over a dozen labs around the world, I mean that the dreamer can communicate with you in the lab. There is sleep paralysis when we are in REM sleep, but there are other parts of the body that are not paralyzed. Even if you move your eyes, you might crash into a wall if you jump out of bed. We are immobile because of the paralysis. The key is that your pet doesn't move.

If you watch your dog in REM sleep, you will see their eyes darting back and forth. This feature can be used by people who dream about left-right-right-right eye movements. They can be picked up by the eye movements of someone sleeping in a lab. You can see random eye movements from REM sleep when you look at polysomnographic recordings of a lucid dreamer. Here is the first signal. I will be carrying out the tasks you asked me to do in your dream. Singing, counting to 10, and even having sex are some of the tasks that can be performed. You send a second signal when you finish. When a person sings, counts, or has an orgasm, researchers can see what is happening in the brain.

You begin to get around the problem of having to wait until the person wakes up to ask them their dream because these people are sort of time-stamping when they begin and end their activities in their dreams. It is mind-blowing to have a person sleep in a sleep lab, fast asleep in REM sleep, dreaming and communicating with you.

Researchers have been able to learn more about how the body and brain respond to different types of dreams. You would expect your brain and body to respond to dreamt activities if you were doing them while awake, and that's what these studies show.

This kind of research got more advanced last year. This is even more science fiction like. Multiple labs across the world, some of them based in Europe, demonstrated two-way communication with the dreamer. These eye signals were communicated by the lucid dreamer. Alfred Murray was one of the researchers who tried to influence dreams in the 1860s.

You have to find a sweet spot where the repeated question can be incorporated into the person's dreams without waking them up. They could ask 8 minus 6, 8 minus 6, or they could flash some lights over their closed eyes in the hopes that these visual stimuli get incorporated. The answer to the 8 minus 6 question is 2 because of two eye movements. You could do these studies with eye movements, but also ask them yes or no questions. Are you a fan of chocolate? If the answer is yes, the person can try to smile like a happy person. If you are looking at facial muscles, you can see small movements around the lips. The person is smiling and that is an answer. Do you like working with yarn? The person can really frown in their dream. If you have a device that monitors the facial muscles around the eyebrows, you will see a discharge, but that is not an answer.

Experiments can ask questions to the dreamer in order to communicate with them in the lab. This is proof of the idea that two-way communication can be had. It makes it possible to tell people to do certain things in their dreams and look at how the brain and body respond. If you stare at an object, if you yell, if you listen to glorious music, if you try to read, you are going to have a great time. It allows us to study how dreams unfold and how our brains and bodies are involved in it. It is actually science and all of this sounds like science fiction.

It is an amazing thing that you are saying. I would like to ask the sort of due diligence question that some of our audience may have, which is, could it be a sham? People might be faking it. Scientists do this and know what they are doing. Tell us the proof that these people are in REM sleep. They are pretending to be asleep in order to be awake. How do we know they aren't awake?

The motor paralysis is one of the key features of REM sleep. Since sleep research has been done in the labs with a few electrodes, this has always been done. Even though you aren't moving your chin, you have a muscle under your chin that shows baseline motor activity. This drops to zero in REM sleep. You can't do this on your own. You only see it in REM sleep. In the studies, the muscles are still paralyzed. The H-reflex is a type of reflexes that only work in REM sleep. You can see their inhibition if you test for them. They can only see REM sleep by the kinds of eye movements that they are making, as well as the strength of their muscles. These people are in REM sleep. They aren't faking that.

It is possible for other people to say, "Oh, I'm doing X, Y, Z." It is possible, and I think it is being done when I look at some videos on the internet. There was great care in showing that the examples that were kept for the data were the ones where there was no doubt on any of these parameters and that this really corresponds.

Strogatz asks if you're in your lab studying dreams.

Zadra said that they have. We studied the treatment of nightmares, as well as the lab clinical applications of lucid dreaming. I am interested in how dreaming can be used to understand how the brain works.

Dream characters are one aspect of dreams that I like the most. Dream characters don't only say and do things that are out of the ordinary. I think we are surprised ourselves when we ask the dream character what they think, because our brain creates them. Dream characters act and behave as if they have their own thoughts. They don't because they're just a creation of your imagination. They look really angry when you meet your ex. If you fall madly in love, or if you are being pursued by someone, they have facial expressions about how angry they are at you. The expressions of emotions, how they speak, and their intonations are all consistent with what we experienced when we were awake. Some of them are two-dimensional. Other characters give us a feeling that they are sentient beings, if they look at you in a way that makes them feel like they have their own perception of the world.

You can use dreams to explore this I have collaborated with an artist in England who uses dreams to create art and I have had him ask dream characters to create art for him. He asked characters in his dreams if they could do a drawing for him. The responses he gets are very interesting. One man told him that he couldn't draw. He said, "Well, because I'm from Czechoslovakia." He had a woman who could draw. And then she said yes. She said she was good at drawing when she was a child. David was surprised by how she has all these skills. She does his drawing after he gave her a sheet of paper. He can see that it is just a bunch of numbers. He said this wasn't a drawing. She said yes. You have to figure out what it all means. Yes, right?

There are all of these examples. Back in the ‘80's, the German researcher Paul Tholey explored some of the questions in dreams about asking dream characters different things. Are you able to sing? I don't know what you're talking about. Dream characters are not good at basic math. Some dream characters will say 4 plus 3, some will say 6. You know the answer because you are the dreamer. The dream character seems to misunderstand what's going on. You had people being asked these math problems, and some would run away, some of the dream characters would just run away, so why is that? They were like, "Oh, no, not math!" in two instances.

Strogatz says we are used to that. I teach mathematics. It happens in real life as well.

Zadra is absolutely correct. This is the nature of these characters. Why do they act this way? Your brain decides to have them react in this manner. How does this affect the creation and evolution of dreams? It is possible to learn more about the neurobiology of dreams, but also about issues of consciousness and how dreams and particular dream characters are created.

Strogatz wanted to make sure he understood the amazing stories you just told. I don't know if Dave Green is a lucid dreamer.

Zadra said that it was correct.

He told you the stories of what happened in his dream when he encountered dream characters and asked them questions. That is how we know what you are saying?

Zadra is absolutely correct. Some of these things have been studied in a lab. Dave is a person who draws on his dreams at first. When he woke up, he would try to remember what he had been saying. He uses his dreams as a form of creativity. I asked him if he wanted to seek out dream characters in his dreams and ask them to do the drawings for him. These stories were sort of related to that.

The research is really interesting. We mention the phrase "dream engineering" before. Is this a dream engineering?

Dream engineering is unrelated to it. This is an emerging scientific field where people are trying to use different technologies and methods to influence people. These external stimuli environments that appear to have an impact on how and what people dream about can be used to make sleepwear. It is an attempt to influence dreams. Flying dreams, which have been shown to work in virtual reality training, are just one example of how this can go from there. Positive smells such as those of a rose or a meal that you like don't get directly incorporated into your dreams, but they foster positive emotions and dreams, just like negative smells don't get directly incorporated in dreams. Different techniques are used to try to influence how and why people dream about something. The field of dream engineering is a very fast evolving one.

There is a group of other dream scientists and sleep scientists who are concerned about dream engineering. Tell us about the letter and what you are worried about.

Dream engineering is a very young field. Some of the first papers on this were published a few years ago. Since we know that sleep and dreams are involved in processing emotional memories, it has a lot of potential to be utilized for therapeutic purposes. Like many new technologies, it has potential drawbacks and scary potential applications. Some examples of this will be given to you.

There are over 40 sleep and dream researchers from all over the world that signed this letter. Our concern isn't so much that things are dangerous now, but it has the potential to be, and we would rather be proactive about making politicians and the general public aware of these issues before it's too late. We are concerned that more and more people are sleeping with sleep related tech, with cell phones that can record any vocalizations during their sleep. It can be useful. If you want to know if you have sleep disorders. What stages of sleep are you in? If you wear a sleep tracker and keep it on at night, you can figure out if you are in REM sleep or not. While we are awake, the brain processes information in ways that it doesn't during sleep. Even if you don't remember any of the events that took place during the night, they can still affect your behavior.

Let me show you an example of this. Smokers who wanted to quit were brought into a lab. They were told that they could give you smells. We want to know how these odors might affect your sleep. You may be in a control group and not smelling anything. That was the end of it. They had to keep a record of how many cigarettes they smoked before going to the lab. They were presented with a combination of rotten eggs and cigarette smell for a short time. It was all done. In the morning, they were awake. They were asked if they could remember any stimuli. Do you recall your dreams? It is not possible to say yes. They don't have a recollection of smelling the smells. They reduced their consumption of cigarettes by 30% after one week.

If you pair while these people are awake, it won't have an effect on their cigarette use. You can do things in people's sleep that are more effective than if you were to do them while you're awake because your brain is processing information in a different way.

Changing people's preference for candy is possible. Do you prefer M&Ms or Skittles before you go to sleep? People will say that they like Skittles. During the night, you can show them something that says "M&Ms, M&Ms", in certain periods of their sleep. They don't remember this. They don't wake up from it. You want to know if they still prefer Skittles or M&Ms when they are done with their sleep in the morning. If I had a choice, I would choose M&Ms. They can't tell you why if you ask.

These are very easy examples. The technology is evolving fast. Advertisers are willing to spend a lot of money to get you to pay attention. Imagine if they were willing to spend several hours of your attention on a nightly basis for which you have no recollection, but for which the effects would be even stronger than anything you could do during wakefulness. We think this is coming down the road. We are bombarded with ads on social media, on highways, on television and before films. We believe that sleep should not be influenced by these types of influences. I don't want my great grandsons to have to pay $10 a month to not see advertisements in their dreams.

Talk about a nightmare. What a great idea. We need to discuss the future of dream research. What about a model that you and Bob Stickgold have proposed called Nextup?

This is a way of explaining the core features of dreams. Many theories of dreams try to explain why they are strange, emotional, or even tied to REM sleep. We came up with a model that tries to explain the experience of dreams while taking into account what we know. We know a lot about the general content of dreams, of nightmares, of everyday dreams, of recurrent dreams, and the different types of dream related experiences we have across sleep stages. Nextup suggests that dreaming is a form of sleep- dependent memory evolution. It tries to extract new knowledge from existing information through the discovery and strengthening of unknown associations to our concerns.

We think that like when you fall asleep, you may have images in your mind that are related to your concerns. This is part of your brain trying to remember what is the most important thing for me to remember in sleep. It's known that in REM sleep you have reduced or absent levels of a brain chemical. The brain probably biases towards accepting dream associations because of this. Serotonin is in the brain and it's reduced. One thing that characterizes these experiences is that they are often imbued with a sense of significance. In REM sleep, the same thing happens. Decreased in REM sleep is a brain chemical called norepinephrine. This allows us to plan ahead. One reason why dreams are hyper associative is because of this. They show how the brain is trying to explore possibilities, trying to make sense of the main events we have experienced during the day, and seeing where they fit in with our conception of the world.

We think that the brain needs to dream and experience in order to make sense of the world around us, as the brain constructs our conception of ourselves and the world in which we live in. This allows us to be better prepared, or our brain to be better prepared, to predict possible future scenarios and how to react to them.

Strogatz thanked Tony. This conversation has shown me a lot about sleep. It has been a pleasure having you.

Zadra thanked her very much for having her and she thoroughly enjoyed their discussion on sleep and dreams.

There will be more episodes of The Joy of Why in 2023. Do you have a math or science question you would like us to answer? To let us know, send an email to joy@quantamagazine.org You can listen to theQuanta SciencePodcast on all the platforms where you can find them. Thanks for taking the time to listen. We want you to join us for more of The Joy of Why.

The Joy of Why is a show that is supported by the Simons Foundation. The selection of topics, guests, and other editorial decisions are not influenced by funding decisions made by the Simons Foundation. The Joy of Why is produced by two people. The editors are John Rennie and Thomas Lin. The theme music was written by a man. The artwork for the episodes is done by Michael Driver and Samuel Velasco. Steve is your host. Please email us at quanta@simons foundation.org if you have any questions. Thanks for taking the time to listen.