Program: Why do we dream?

Norman Swan: So Tegan, did you dream about me last night?

Tegan Taylor: I didn't, but it's funny you should mention that, because I have had a dream about you before, Norman. Well, it was a work dream. Do you want to hear it? 

Norman Swan: Okay, it sounds like a nightmare, but carry on. 

Tegan Taylor: It was, this is the thing. This is a while ago now, but oh gosh, dreams are so emotional, like it all comes flooding back. I had a dream that we had to be on the radio and I couldn't get the printer to work, and I couldn't get in to the studio, and I couldn't get my mic to go on. It's sort of like I was wading through mud. But the worst part of the dream was Norman was mad at me.

Norman Swan: Never!

Tegan Taylor: The overwhelming kind of emotion attached to that dream for me, it's like; Norman's gonna be so mad at me.

Norman Swan: Did I talk with this kind of '30s noir movie hiss?

Tegan Taylor: 'You'd better get in here, Sunshine, or you're fired.' No, it was more like your presence, your disapproval, that was the spectre over the dream. Have you been dreaming about me?

Norman Swan: Look, I must confess that I, too, have had dreams about not being ready. You know, it's so common, and you're sitting there and either I haven't read the script (that's not unusual), or the script's not ready and that was my job to get the script ready. The other dream I have, actually…so this will ring a bell with anybody listening because it's such a common story with dreams, is that at least once a year I'll have a dream that I've still got to do my medical exams.

Tegan Taylor: Yes, oh my gosh, yes. Well, not medical exams, but yes, this idea of some hangover from your teens or 20s, you're like, 'But I'm a grown up now!'

Norman Swan: Yeah, you know, and what if the Daily Mail finds out that I've never done them?

Tegan Taylor: That's so relatable. Oh well, let's get into it, because of course today we are talking about our dreams and what do they mean.

Norman Swan: In What's That Rash?, the show where we answer the health questions that everyone's asking.

Tegan Taylor: So today's question comes from Siobhan, who says, 'Can you talk about dreams?' Well, Siobhan, we already have, at length. 'Why does the brain dream during sleep? Is it debriefing the day? I dream every night and often wake exhausted. My husband doesn't recall his dreams. What happens to the brain while dreaming? Is it healthy or unhealthy for the body? Do dreams vary in length from person to person?' And then she signs off, 'Keep up the great work and keep ringing that Mediterranean diet bell,' ring, ring, I will. I don't know if we're gonna have cause for the Med diet bell today, Norman.

Norman Swan: Well, we can work it in. We'll try.

Tegan Taylor: So many questions from Siobhan, but they all kind of follow from each other. So I think we're going to be able to touch on almost all of that on our way through today. Can we start with actually what are dreams? What is dreaming?

Norman Swan: We'll get into why in a minute. We know what dreams are. Dreams are stories that you go through in your mind during sleep, and they're usually self-referential, or you play a role in the dreams. They're often in black and white, but they can be in colour. Nobody's worked out what the difference is in terms of your brain function when you have colour dreams versus black and white.

Tegan Taylor: I never thought about my dreams being in black and white before. I don't think they are. 

Norman Swan: I think mine are black and white.

Tegan Taylor: That's because you're old. Mine are in technicolour.

Norman Swan: I grew up when there wasn't even sound in the movies.

Tegan Taylor: Sound and dreams. Your dreams have those flashes that come up with just a sentence, like a Charlie Chaplin movie.

Norman Swan: That's right, the plate there saying 'How dare you say that?' And other people get, which is rare…other people get dreams where it's actually just sound. And there have been stories of composers who've come up with melodies that they've reckoned they've dreamed about. And Paul McCartney is famous for having come up with…

Tegan Taylor: He reckons 'Let It Be' and 'Yesterday' both came from a dream.

Norman Swan: Yeah. And there is a relationship here between creativity and dreaming, which we can come back to.

Tegan Taylor: And some people have got so many dream stories, like famous things that people said came from dreams. We could do a whole podcast episode about it.

Norman Swan: We could, and we're not, because I haven't read the script. Now I'm getting sort of one of these dream things, I haven't got the script for that, haven't got a script for that. So there are elements. So for example, some of the dreams that you hear about, these creativity dreams, are ones where you're just falling asleep, and those are called hypnagogic dreams, you're just in that semi-conscious state before you go to sleep…

Tegan Taylor: Oh, where you feel like you probably wouldn't think you were asleep until you wake up, and then you're like, oh my gosh, I was actually asleep.

Norman Swan: And those are probably the ones where you more likely to remember what you dreamt. And there's a whole thing about remembering your dreams. How often do you remember your dreams?

Tegan Taylor: I don't know. Like, you only remember the ones you remember, right? Like, am I dreaming every night and I just can't remember them, or do I only dream the nights I remember them?

Norman Swan: No, you're dreaming every night, almost certainly.

Tegan Taylor: Really? Okay.

Norman Swan: Almost certainly everybody dreams. And you tend to dream during REM sleep, so it's rapid eye movement sleep, but you do dream at other times, as we've just said, but REM sleep is probably not restful sleep, but you go into it a couple of times a night. The first sequence is fairly short, and then it becomes longer later, and that is thought to be the time when you are dreaming, but apparently you can dream at other times. 

And Siobhan asks about restful sleep. There is some evidence that nightmares are associated with a disrupted night's sleep and waking up feeling exhausted. Insomnia is related to an increased frequency of bad dreams. So people who have bad dreams tend to be insomniac, or have a higher risk of being insomniac, and some people who are insomniac tend to have more bad dreams. Now, it's not quite clear which direction that is going.

Tegan Taylor: Yes, because you could imagine if you were anxious about falling asleep, you're falling asleep in a negative state of mind, but also if you were scared of having nightmares, you're less likely to let yourself pop off to sleep, and you're going to be more tired, I can see how that could sort of feed from both ends.

Norman Swan: I mean, I used to get a regular nightmare when I was a child, exactly the same nightmare, and I used to know when it was coming on. 

Tegan Taylor: Oh gosh, that would be scary. 

Norman Swan: I got this sensory abnormality. Some people think it's a form of epilepsy. They've gone away from that idea, but it's probably a form of midnight terrors in children. It was the same nightmare every night, and I used to sleepwalk during the nightmare, and it went away with puberty. And I could never explain where this weird nightmare came from.

Tegan Taylor: You've told this story before on What's That Rash?…

Norman Swan: Have I? I'm sorry.

Tegan Taylor: No, no, no, it's great. I want to leave it there and see if anyone can remember…

Norman Swan: My dream?

Tegan Taylor: Yes, because Norman has told this story about his dream before, and then he told us its provenance at the end of the story, which I think was maybe a year or so ago, Norman, we did a story on night terrors. And if you remember that and you remember what Norman's dream inspiration was, then email us, thatrash@abc.net.au and we might give you a prize, and the prize will be our approval, nothing physical. Actually, we do have some magnets. Let's see how we go. If you're feeling lucky, let us know what you reckon Norman's dream inspo was. Anyway, sorry, back to Siobhan's question.

Norman Swan: And a What's That Rash? fridge magnet could be on its way to you. This is a collector's item. The short answer to Siobhan's question is that people have got lots of theories as to why we dream, but nobody fully understands it. It's thought to be a clearing-out process of the day's thoughts. It's thought to be a process where we lay down memories. It's thought to be a process where we work out problems while we're asleep. And some people think there's no meaning at all to dreams, it's just something our brains do when we're asleep.

Tegan Taylor: Is there any way of measuring what's happening in a…like, the whole idea about memories or problem solving, is there any way beyond people reporting things or just sort of tracking electrical activity that we could prove what's happening inside a brain?

Norman Swan: People have tried to do it with lucid dreaming. 

Tegan Taylor: So that's where you realise you're asleep, and you can maybe sometimes kind of control what happens in your dream. I find if I get there with a dream, I'm waking up as that's happening.

Norman Swan: Yeah, I'm not aware. I can often wake up and remember exactly what was in a dream, and it's usually because it was quite funny and bizarre, and I just want to tell somebody about it, because guess who was involved and which prime ministers were…whatever the story might be. But yeah, you're right, lucid dreaming is where you are semi-conscious of the dreaming process, and what they've tried to do is teach people to move their eyes while they're asleep, when they're having a lucid dream, so that they could pick up the brain waves while they're doing that, to see if they can detect any particular dream specific brain waves. 

Tegan Taylor: I think the study that you're gesturing at also comes to another facet of dreaming that has always intrigued me, which is time in dreams, because I remember hearing once, sometime, at some stage, that dreams only last, like, you know, 20 seconds or something like that. But in your dream, it can feel like years are going by, and they were trying to get people to say how long doing an activity took them in the dream versus how long it took them to do that thing in real life.

Norman Swan: Have you seen Inception?

Tegan Taylor: I have. And that captures that, amazingly, in that movie. I mean, it's a fantasy movie, but it captures this notion that you get these long narratives that are only a short space of time in your sleep cycle.

Tegan Taylor: So is the study that you're referring to the movie Inception, or is there some science here too? 

Norman Swan: Just the movie. I believe what I see in movies. Movies are my main source of scientific information. Not.

Tegan Taylor: Well, lucky for both of us there's also been some science around this. There was one particular study that stood out to me, which I was saying before, where basically the researchers got people to do an exercise like a squat or a forward roll or whatever in real life, and timed how long it took them, and then they did that thing where they were lucid dreaming, and they would indicate to the researcher by moving their eyes left, right, left, right at the beginning and at the end of the task in the lucid dream, so that the researchers could see. 

Norman Swan: So, they did a few squats in their head.

Tegan Taylor: Well, the actual things that they did were walking ten steps and a gymnastic routine. Presumably they were able to do the gymnastic routine in real life as well. But basically one of the participants talks about going outside in the dream, trying to find a spot where they had space, and then going into a garden, and then, okay, I'm doing the experiment now, moved their eyes left, right, left, right, and then jumped. 'And I felt immediately that jumping was very different compared to wakefulness. I also continued, and I did the forward roll, which lasted almost eternally, and then did the left, right, left, right again.' The eternal forward roll in your dream. 

Norman Swan: And the conclusion was?

Tegan Taylor: The conclusion is that it took you longer in your dream to do the tasks then it did in real life. But also their perception of time was even more extended. Time dilation. It's almost like Inception meets Interstellar. What do you want to talk about? 

Norman Swan: So there's something called…which is controversial among some neuroscientists, although there's been about 8,000 papers on it, it's called the default mode network.

Tegan Taylor: It sounds boring. 

Norman Swan: It's not boring at all. So they've only known about it for about 30 or 40 years, because they noticed it when they started doing functional brain scans.

Tegan Taylor: It sounds like a wi-fi issue, like 'select your default mode network to connect to the wi-fi'.

Norman Swan: That is actually quite close to the truth. If you're going to put yourself in a scanner, or get put in a scanner to find out what happens when your arm moves, or when you're thinking about an exam or something like that, what part of your brain lights up? They've got to get a baseline in your brain to see what your brain is like at rest, so that when you do the task that you're given, there's something new to see in the brain over the bass line. So what they thought in the beginning is that when you put somebody in a scanner and you didn't give them any sounds, or you weren't talking to them, you weren't asking them to speak, they were completely at rest, that the brain would go quiet. The brain did not go quiet. The brain lit up. That's why it's called the default mode network because that's what the brain defaults to when you've got no sensory input. And then as soon as you gave somebody the task, this network went quiet. So it lit up when you were at rest, and then went quiet when you were trying to do something, when you were doing a task. 

Now, the default mode network is associated with memory. It's associated with how our brains compensate for ageing, for example. And it's at different levels, whether you're a creative person or not, for example. So what the default network does (and it's not one network, it's actually lots of little networks around the brain) is that it's like the traffic manager in your brain. And when you're at rest, the default mode network tends to activate, and in some people it activates strongly, and in some people it doesn't activate so strongly. And when it doesn't activate so strongly when you're at rest, your mind wanders. 

And it's thought that mind wandering is actually a function of how heavy or light your default mode network is switched on when you're at rest. You can call it daydreaming, if you like. And creativity is thought to be when you've got a very light touch default mode network, which allows parts of the brain to talk to each other that wouldn't normally talk to each other. Sound familiar with dreaming? That's what happens with dreaming, is that you get this cross-talk in the brain. And here's the thing, at least one study has shown that creative people are more likely to remember their dreams.

Tegan Taylor: That is so interesting, and it really speaks to what you were saying before about composers who compose music that's based on their dreams, that these people who are in creative problem-solving fields, their dreams are sort of part of that process. That's so interesting, and it also gives me a great segue into talking about some of the famous things that have been invented from dreams. Have you heard the sewing machine invention story before?

Norman Swan: No, did somebody get their finger caught when they were having a dream?

Tegan Taylor: No. Elias Howe is the guy who's credited with inventing the sewing machine. And whenever I think about a sewing machine, I can never quite figure out how they make the thread go in and out… anyway…

Norman Swan: That's right, that's right. It does your head in. 

Tegan Taylor: It does your head in. Anyway, old mate was having a dream. I don't know if he was trying to figure out how to make one already, but basically he dreamed he was building a sewing machine for a savage king in a strange country, and he was perplexed about the needle's eye, and the king gave him 24 hours to make the machine, otherwise he was going to be killed. And he was about to be executed in his dream, and then he noticed that the warriors were carrying spears that were pierced near the head, and then he realised that the eye of the needle needed to be at the end, the pointy end of the needle. And he woke up at four o'clock in the morning, and by nine, a needle with an eye in the point had been modelled, and he got the sewing machine going after that. 

Norman Swan: Amazing. 

Tegan Taylor: See? The power of dreams. And Yesterday, by Paul McCartney.

Norman Swan: And there's a difference between men and women dreaming. 

Tegan Taylor: Yeah, I'm really, really interested to talk about this because I wonder how much of it is sex based, and how much is like cultural, gender based, right? So pretty much what the researchers found was that women were more likely to remember their dreams, but also women's dreams are more likely to have emotions, they've got more characters in them, maybe people who are familiar, more likely to be inside, include household objects and references to clothing.

Norman Swan: So, not a romantic fantasy novel. 

Tegan Taylor: It's funny you should say that. Men's dreams are more characterised by physical aggression, sexuality, achievement and the occurrence of weapons, including, presumably, spears with needle eyes in the tips of them. So how much of that do you think is maybe gender specific, and how much is just what's in your mind as you're going to sleep. If you've watched an action movie before you go to sleep, are you more likely to dream about weapons because that's what's in your mind, or because you're innately more, I don't know, conflictual?

Norman Swan: So there's a common thread in dream research, which is that one aspect of dreaming is reprising the day and reprising your current situation. And of course the other thing that people don't think about too much with dreams is that drugs can make you dream, medications can make you dream. So I think one of the pieces of feedback we got recently when we were talking about jetlag, a listener sent a note that melatonin, which is one of the things that we talked about not having very many side effects, and this listener said, well, dreams are a side effect of melatonin. So active dreaming, vivid dreaming, is a very common side effect of taking melatonin. There are a lot of drugs that can cause vivid dreaming. Isotretinoin, which is a drug for acne. Antidepressants can cause both negative dreaming but also pleasant dreaming. There's a drug for diabetes called Metformin, and it's rarely associated with abnormal dreaming. Beta blockers for high blood pressure can be associated with nightmares. So if you're having a surge of dreaming that you're not enjoying, have a think about what drugs you're on.

Tegan Taylor: Well, to come to one of Siobhan's last questions, is it healthy or unhealthy for the body? Like, how much store should we put in our dreams or lack thereof?

Norman Swan: The answer is, Siobhan, your husband's dreaming and your dreaming is part of a healthy brain, reprocessing, getting ready for the day, doing whatever it does, or it's a random activity created by this default mode network. Either way, it's just part of life.

Tegan Taylor: Well, Siobhan, thank you so much for the question. I wish you and your husband both a safe and restful sleep tonight, either with or without dreams, whatever your choice is. And if you've got a question you'd like us to try to tackle, email us, thatrash@abc.net.au.

Norman Swan: And what's in the mailbag? 

Tegan Taylor: Well, speaking of sleep, we were speaking a couple of weeks ago now about basically different things that help you go to sleep, or maybe make you go to sleep before you're ready.

Norman Swan: Oh yeah, why do we fall asleep in front of the telly, that's right.

Tegan Taylor: Why does Costa from Gardening Australia seem to be so soporific? Anyway, Anna has emailed us in an email titled 'Soporforicity of ABC Presenters', saying, 'Richard Fidler, soothing and soporific voice. I have audio books of all of his self-narrated history books, and if I'm sleepless at 3am I listen to his melodic descriptions of the brutal ancient wars of Middle Eastern Europe, I'm out like a light in no time. So maybe the voice is the thing, regardless of whether the topic is wars of religion or battles against invasive plant species.'

Norman Swan: We won't tell Richard. We're keeping a secret from Costa and Richard.

Tegan Taylor: He might take it as a compliment.

Norman Swan: Knowing Richard, I'm sure he would. The interesting thing is occasionally I've fallen asleep to an audio book and I've dreamt, so it's induced a dream.

Tegan Taylor: Actually, Norman, I can't believe we've come through this whole episode without mentioning Shelby Traynor, our producer, What's That Rash? producer Shelby Traynor, her episode of All in the Mind that she did about a year ago on something called the Tetris effect, which is basically where if you play Tetris you can see the bricks falling in front of your eyes as you're going to sleep. And they actually use it as a tool for people who have gone through traumatic experiences to help them decouple that part of their brain to help them deal with that trauma. 

Norman Swan: So we dream of Tetris. 

Tegan Taylor: Dream of Tetris, dream of Richard Fidler and wars in the Middle East, whatever floats your boat.

Norman Swan: And Stuart writes, because we just keep on getting responses to our No Poo episode, which, I hasten to add, was not about constipation…

Tegan Taylor: No, it was about shampoo and conditioner. Anyway, Stuart says, 'I took to heart the key message of your No Poo episode, which was clearly, shampoo is bad, conditioner is good.' I don't know if that's actually where I came down. That's interesting, that that's Stuart's interpretation. 

Norman Swan: Yeah. What we really said was…well, you can go back and listen for yourselves; shampoo bad, conditioner bad, if you believe in it. But carry on.

Tegan Taylor: Anyway, Stuart says, 'Shampoo has always made my hair dry and frizzy, even after conditioner. So I figured why not ditch the shampoo and just use conditioner. Massaging with conditioner would help carry away any dirt, and I would be left with beautiful, soft, silky and manageable hair. Well, that didn't happen. Still clean, but still dry and frizzy. Anyway,' Stuart says, 'I've gone all the way. I wash my hair in plain shower water, massaging the scalp briefly. I leave it like that while I finish my shower, then rinse it out with more plain water. After three weeks of this, my hair appears just as clean and is not as frizzy as it was, but it's certainly not greasy. So now I'm free of the scam-poo,' says Stuart.

Norman Swan: Thanks Stuart. And we look forward to any of your comments on any of our shows.

Tegan Taylor: Yep, just email us, thatrash@abc.net.au.

Norman Swan: See you next week. 

Tegan Taylor: See you then.