Horizon (1964) s47e03 Episode Script

Why Do We Dream?

Tonight nearly all 61 million people of this country will fall asleep, and each and every one of us will dream.
There were two lanes on the motorway so it was a normal motorway apart from the fact that all the cars had no people in them.
I'm holding a big glass of milk and there's a head of lettuce in it.
She was very overweight and actually was growing a real beard.
It's an extraordinary world full of pleasure and pain.
I descended from the sky onto this sort of beautiful .
I've been choked and stabbed and I've been shot But why we dream is one of science's great mysteries.
I don't know anybody who isn't fascinated by dreams.
I mean they are outrageous events in our lives.
It's only now that science is beginning to reveal the bizarre complexities of this secret world.
Why would Mother Nature highly activate your brain, paralyse your body, sexually activate you and force you to watch these things we call dreams, why? Why would Mother Nature do that? Much of what we thought we knew about dreams appears to be wrong.
Without nightmares there is a good chance that humanity wouldn't be here at all.
Where do our dreams come from? If you want to understand human nature, the human mind, what makes us tick, you need to look at dreams.
Do our dreams have meaning? People intuitively know that there is something about their dreams that is meaningful.
People are endlessly fascinated by dreams.
Can we use our dreams? Those people who dream about it actually end up performing better the next time.
Throughout human history there have always been big ideas about the origins of dreams.
For decades people thought dreams were all these so spiritual things and you know they are.
It's all about hidden sexual desires, it's all nonsense.
Scientists have long held the belief that dreams have a purpose.
Dreams have been responsible for two Nobel prizes, the invention of a couple of major drugs, other scientific discoveries.
When you share a dream with somebody, you're saying here is some information about me that I haven't faked.
and therefore it's reliable, and therefore it might reveal something interesting about me.
But it was not until 55 years ago that neuroscience really began to study the dreaming brain.
Then American sleep scientist Nathaniel Kleitman undertook a series of remarkable experiments.
He measured the brainwave activity of his subjects whilst they slept.
Rather than seeing the passive picture most scientists expected, Kleitman found quite the opposite.
What they found is that yes, they seem to fall asleep and you got these big waves but then after not a very long time it became fast and low amplitude again as if they were awake but they weren't.
So it looks like while you're asleep, the brain can shift between different states, different stages of sleep we say now, some of which looks very much like wake.
And when Kleitman examined these active sleep cycles, he noticed something else - the sleepers' eyes appeared to be blinking.
Kleitman called it Rapid Eye Movement, or REM sleep and it would lead to his greatest discovery.
During REM sleep, what the researchers invariably found when they woke up a subject was the subject would say, "I'm dreaming.
I just had a vivid dream.
" Kleitman had pinpointed when we dream but he found while our brain and eyes were active, the effect of REM sleep on our bodies was exactly the opposite.
Another feature of REM sleep is that your muscle tone just goes absolutely down to zero.
You become functionally paralysed.
If you're sitting up in a chair watching TV, and the head nods and falls and you fall asleep, that's not REM sleep.
If you fall into REM sleep, you would literally roll off the chair onto the floor because your body becomes absolutely relaxed, almost paralysed in the sense that you can't make your muscles actually work and it becomes absolutely calm and non-responsive.
Kleitman and his team had made the first step in explaining our dream lives but it would take some far more audacious experiments to enter further into the secret world of dreams.
This cat looks as if it's awake.
In fact, it's fast asleep.
A dog appears to try running.
It too is asleep.
In order for these dreams to be seen, the animals were subjected to radical surgery.
Scientists removed the part of the brain responsible for paralysing the muscles during REM sleep.
And what we see is that when you do this, with cats in particular, is that they, they can walk around during REM sleep and their behaviour is not random, it's not chaotic.
They're not just doing any old crazy thing.
They appear to be doing the kinds of behaviours that cats like to do like stalking a prey, you know play with a mouse or something.
So presumably that's what they dream about when they go into REM sleep.
So that's what we think is happening.
These experiments gave scientists an insight into the dream world of animals.
Repeating such radical surgery in humans was unthinkable.
Researchers still sought a way to observe people living out their dreams.
One rare brain disease offers a possible answer.
Well, I'm not an aggressive person.
No, not aggressive at all but he is when he's got It's a Jekyll and Hyde thing.
Yeah I'm saying Tommy, stop it, stop it! Stop it! And I said what are you doing and he said "I'm picking the parrot up.
" And I said, "You what?" And he said, "I'm picking the parrot up.
" And he don't even know that he's told me that, do you? No.
Tom and Tina Cursley have been married for 42 years.
Three years ago Tom retired from running a garden centre and that's when he started to cause a rumpus in the bedroom.
Well, it was me telling him he's got to go to the doctor's and sort this out because I'd have to jump out of bed quick.
I'd think I was running and kicking, and my arms were going I didn't know what he was going to do cos he was aggressive.
Tom had begun to act out his dreams and there was one that caused him to be particularly energetic at night.
I can picture now being in this field, a river in the background and I don't know, about a dozen cows grazing the grass and they suddenly started coming towards me and there's this high fence all round it and I'm backing up to the fence, getting out of the way but they keep coming.
And I try and jump over the fence but there's no way I could jump over it.
The cows keep coming and nudging me and push me out of the way.
As he dreams, Tom thrashes about the bed.
He's just horrible really.
He's shouting and raging about everywhere.
The bedside cabinet went over the other night and he didn't even know he'd knocked that over but everything went flying, didn't it? Yeah.
Light, clock, tablets, and he never even woke up.
It is, it is awful because I mean, why is he doing it? Tom is suffering from a rare brain condition called REM Sleep Disorder.
Dr John Shneerson is one of Europe's leading experts on this condition.
It's absolutely classical for the REM Sleep behaviour disorder.
It starts off with movements that the partner thinks is a bit unusual but nothing special, just kicking and just a bad dream, but it becomes more frequent, more intense and it can be dangerous for the partner and dangerous for the dreamer who may dive out of bed and have quite severe injuries.
A lot of people with this condition end up with nothing in their bedroom.
They take out all the bedside tables, all the lamps, all the sharp corners, which might injure themselves.
They end up almost in a padded cell.
The condition is caused by a gradual destruction of a part of the brain stem called the Pons.
The Pons controls the muscles in REM sleep and the disorder is in some cases a pre-cursor to Parkinson's Disease.
Some sufferers who have a more severe form of the disease demonstrate very vivid dreams.
As in this video, a sleeper puffs on his finger monitor, dreaming that it's a cigarette.
Here a French veteran dreams of marching on the parade ground.
Another patient was dreaming that there were animals coming in the room and he woke up on the mantelpiece and found it difficult to get off.
He didn't know how he got up there.
He must have been very agile, very motivated to get that far.
It's only a tiny part of the brain which prevents us from acting out our dreams.
Part of the activity of REM sleep is to turn off the connections between these centres in your brain and the muscles themselves, so if you have, you could have all sorts of thoughts and activity within the brain, and nobody could see it from outside.
Whilst for the sufferer REM Sleep Disorder can be unbearable, for scientists it fulfils the ambition of seeing somebody else's dream in action.
After 55 years of delving ever deeper into the sleeping brain, the new cutting edge of dream science is dramatically changing our understanding of dreams.
Erica Harris is one of the new breed of dream scientists.
As most other people battle the rush hour to get home, she's arriving for work at Boston University, a world centre in this ethereal field.
The experiment tonight won't probably end till about 6.
30 or 7am when we're finally done.
It's very tiring but we enjoy our work so we're looking forward to it.
Also arriving is her guinea pig Ross, a 19-year-old student who has come here for a bad night's sleep.
Hello! Oh, hello, I'm Ross.
Hi, Ross.
The aim of the next eight hours is to measure the emotional journey that Ross is going to undertake as he dreams through the night.
This is to measure any different type of muscle movement that he might have at his eyes or at his chin.
We need to measure the brainwaves because the brainwaves look different depending on the different type of sleep that the person goes in.
The researchers will monitor his every brainwave and movement throughout the night.
There are 26 different electrodes that Ross will have on tonight.
We're going to have a pretty good idea about everything that is going on with him while he's sleeping.
Even with all this technology, there is still only one way to find out whether Ross is dreaming.
Sweet dreams.
The project leader is Professor Patrick McNamara.
There is no technology that allows us to know 100% certainty that a person is dreaming.
You can see the full panoply of characteristics that occur during REM sleep - the paralysis, the eyes darting back and forth.
You can put him under a neuro-imaging scanner.
You can see the areas of the brain that light up during REM sleep light up and you can expect them to report a dream when you wake them up but they may not.
Unfortunately the best way to find out if a person is dreaming is to wake them up and ask them.
Despite this limitation, the experiment will examine how our dreams play a central role in our mental well-being.
So this should tell us something crucial about the nature of the mind because if you want to understand human nature, the human mind, what makes us tick, you need to look at dreams.
It's now eleven o'clock in the dream labs in Boston, and Ross has gone to sleep.
But it's going to be a long hard night.
Our sleep is divided into 90-minute cycles.
The first two are dominated by deep sleep when our brain is mainly passive.
After that we alternate between REM and non-REM sleep.
On this monitor we are looking for him to descend into the various stages of sleep so we want him to make his complete sleep cycle prior to us awakening him.
Ross has entered the first cycle of REM sleep where we know dreaming takes place.
But thirty minutes later he starts another stage of sleep, called non-REM sleep.
Right now what we can see is that he's in non-REM sleep, because the shape of the brainwaves are very close together like this, and then we see some that are very spiky.
This is the beginning of the transition to the stage in which we want to wake Ross up.
Dream scientists used to think that this was just an insignificant stage of sleep and that we only dreamt in REM sleep.
But the great surprise of the past few years is the discovery that we dream in non-REM sleep as well, as the experiment confirms.
It's four o'clock in the morning.
Ross, wake up, it's time to do your packet.
Ross is woken from non-REM sleep and does indeed report having a dream.
I was with people I knew, no real friends as specific but I was with people I knew and we were trying to find somewhere.
It is not just that we dream in non-REM sleep.
This groundbreaking experiment is starting to find that these two dream worlds are fundamentally different.
So the first thing that he's working on right now is a mood questionnaire and basically he might see three letters like O P and he's supposed to complete some kind of word for that.
The words Ross chooses will indicate how positive he's feeling about himself in non-REM sleep.
He appears to be feeling very good about himself.
We found in our experiment there was a very reliable difference in self-concept, self-regard and there was an increase in positive regard of the self after awakenings from non-REM.
Ross goes back to sleep.
The next time he's woken he will be well into REM sleep.
5 am.
Ross, time to wake up.
This time Ross reports a number of negative words.
McNamara speculates that the difference in the nature of these dreams can be traced back to an ancient structure of the brain called the amygdala that is linked to our emotions.
I think that we have more negative emotions during REM-related dreams because during REM sleep, the amygdala is very highly activated and the amygdala specialises in handling unpleasant emotions like intense fear or intense anger or aggression.
Finally the long night is over and Erica goes home, but the experiment has more to reveal.
McNamara is beginning to connect the balance of REM and non-REM dreams with the mental well-being of us all.
It could be a factor in depression.
Normally we fall asleep through non-REM sleep but depressives, people with endogenous depression or severe depression, they go right to REM and then they stay in REM and they spend too much time in REM.
So if REM sleep is associated with all this unpleasant emotion and you get too much REM, then you are going to have a lot of unpleasant emotion.
We call that depression.
So decades after the discovery of REM sleep, scientists are beginning to understand the extent to which dreams shape our waking lives.
I descended from the sky onto this kind of beautiful fairytale planet.
I had a flat cardboard box, you know those ones that you assemble together, and I took it up to this pyramid and it had a severe drop at one end and I put it together.
And then I jumped down off the pyramid in the box and hit the pavement but the strange thing was it didn't actually hurt.
There's like this kind of spaceship in the sky, very scary and all the water puddles if you touched them you had, you catch on fire.
To find out why dreams are so central to our lives, one man has studied those who don't dream.
I frequently found when I ask patients after they have sustained strokes whether they are dreaming or not, initially they're not entirely sure and then it's in the following days because they are now paying attention to their dreams that they report to me that they are no longer dreaming.
Many of us believe we don't dream.
In fact most of us do, it's just we can't remember them.
But Professor Mark Solms has spent much of his career waking the rare individuals who really do not report dreams.
Following a stroke three years ago Heather Jones had just such an experience.
Before my stroke I definitely was someone that had lots of dreams.
After my stroke it was just, literally going to sleep was like going into a blankness.
It's almost as if you're just absent for a while.
There was just not that same sense in the sleep or when I was waking up that I'd been dreaming.
There was no memory of dreams and no sense of having been dreaming.
Heather's stroke affected a part of the brain called the parietal lobe.
Solms believes this is where dreams are made.
People with parietal damage, like Heather sustained, frequently stop dreaming completely in the early stages after the onset of the damage.
That's because the parietal lobe serves the purpose of combining our different senses, hearing and vision and touch.
All come together there and the imaginary space that we are living in during our dreams is generated in that part of the brain, so if it's damaged you can't dream.
This loss of dreaming has debilitating consequences as Heather knows only too well.
Although I could go to sleep very easily, I wasn't having what I would call good quality sleep.
At night probably waking several times through the night so I wasn't getting a continued sort of period of sleep.
When I woke up, I just felt tired still.
The relationship between sleep and loss of dreaming is in fact something that I'm busy researching at the moment.
Our preliminary findings suggest that at least non-dreaming patients fall asleep perfectly easily but then they keep on waking up throughout the night, in fact particularly during REM sleep.
It's almost as if when you might have expected that they would be dreaming, they wake up.
As bizarre as it may seem, Solms suggests dreams could be a way of keeping us asleep.
Solms has found that another part of the brain, the motivation system, is also active during dreaming.
And this has given him a further idea about the reason why we dream.
The fact that this part of the brain, the seeking system, is so active in dreams, suggests that dreams, at minimum we have to say that dreams have some kind of motivated search in them.
We're seeking something in our dreams.
It may be the actual storyline of the dream when we find ourselves wandering about some strange landscape looking for something.
Maybe that's how this expresses itself.
Solms believes that this seeking activity symbolises the search for answers.
More likely, cos it's a more general an explanation, is that we are grappling with some sort of problem in our dreams and trying to find a solution to some matter of current concern.
There's a kind of a searching involved in that.
In time, Heather made a recovery and once more she was able to benefit from dreaming.
It was an excitement really when I began to dream again.
I did tell people about it.
I told my partner, I told my physio cos it was something that I hadn't thought would return.
If you're aware of having dreamt, that contributes to a feeling you've had a good night's sleep.
And that's certainly how I feel.
So science has revealed that dreams may have many purposes, a good night's sleep a way of seeking solutions.
They may even be a way of maintaining our mental health.
I was playing in my room with my sister and then I was about to go outside and my mum said, keep your head up because there is a witch about.
I was in the kitchen.
I remember it had really bright colours and a lot of sunshine and I saw a bug on the table and I heard it say, "hamburger, hamburger.
" I take off and fly and I'm starting to accelerate faster, faster, faster and I realise I was an electron inside an RCA circuit moving around at the speed of light.
Whilst science has begun to unravel many of the mysteries of dreams, there is one question that has endured more than any other.
Do our dreams mean anything? My interest in dreaming as a scientist is boy, I just want to understand these things.
It's just so interesting and so exciting.
What is more interesting and fascinating and psychological than dreaming? People intuitively know that there is something about their dreams that is meaningful.
People are endlessly fascinated by dreams.
This belief that dreams mean something has been shared across the globe and remains central to many cultures.
Deep in the forests of Northern Canada on the banks of Sesikinikak Lake, live the Itikemek people.
Interpreting the meaning of their dreams is at the very core of the tribe's belief.
The Itikemek gather for their morning dream circle in which they share their dreams, the elders drawing on their folklore to tell them what they might mean.
Marianne is the elder and most versed in understanding dreaming.
In the dream circle Pauline tells of a second dream about her son Ivan, a drug addict.
For the Itikemek, the question of whether dreams have any significance is beyond doubt.
But is it possible for science to find out what they might mean? Throughout the 20th century many psychologists, led by Sigmund Freud, thought dreams were symbols from our unconscious mind which need to be interpreted.
Now in the Canadian city of Montreal the power of modern mathematics is being used to tell us what dreams mean.
There is convincing evidence that leads us to believe that the content of dreams tell us a lot about how the brain can process information, and is important for our psychological well-being.
Antonio Zadra is a scientist in the University of Montreal's dream lab.
Here he's collected thousands of dreams.
Each has been analysed to see exactly what it's made of.
This rich content is then turned into numbers.
Well, what we did is we coded the entire dream series in terms of various elements.
Who are the characters, the emotions, the settings? And then we entered these quantifications, these resulting numbers in our spreadsheet.
The result of this painstaking process is a comprehensive database of our dream lives.
Zadra can tell us how often we dream about sex, and whether it involves our partner or even a celebrity.
He can even tell us how often we have negative dreams.
But his database doesn't explain the many.
It is most revealing when telling us about the dreams of an individual.
We want to see a whole series of dreams so that we can then detect patterns that recur over that entire dream series and thus get a better idea of what this person's dream life is generally like.
By comparing these elements against the norm, Zadra can interpret what someone's dreams mean.
This is a series of dreams from a 48-year-old professional man.
He calls his wife B.
B and I are making breakfast.
I was also brewing some coffee but when I looked over at the coffee maker it was overflowing.
There was coffee all over the counter and coffee just kept pouring out B kept on yelling what did you do, what did you do? I tried unplugging it I removed the glass container but it wouldn't stop.
His mother arrives, he's inconsolable and parents too.
But the mother keeps telling people it's all my fault, it's loud and I try to defend myself like wake up.
And from this series of dreams Zadra spots misfortune as a recurring feature.
When I tried to move the car the wheels just kept spinning B was getting very upset and was telling me there was still too much snow.
I got out again and everything seems OK I got back in but nothing happened just more spinning In fact 80% of these dreams contain some sort of misfortune.
Yet on his database, Zadra finds the average occurrence of misfortune in the dreams of middle aged men is just 30%.
The other thing that really stands out with his dream series is that almost all of the other characters in his dreams are women.
There's an, almost an absence of male figures and the interactions he has with these women is almost invariably negative.
Once more the frequency of these negative dreams about women is far higher than the norm.
If I were to make an educated guess about what is going on in this particular man's life, is that there seems to be concerns about relationship issues and also he is definitely overwhelmed by factors which are impacting him negatively but which he feels he has no control over.
So it came as no surprise to Zadra to learn what happened to this couple.
Five years later they divorced.
Zadra has worked out the norm for many dream events.
Only a fifth of woman's dreams about sex involved their partners but for men it's even less, just a sixth of the time, and women should be dreaming about having sex with celebrities twice as often as men.
But sadly more than three-quarters of our dreams are negative.
Most of all, the database reveals that our dreams are a much more straightforward reflection of our waking concerns than previously thought.
Dreams do not hide their meanings but are relatively transparent and I think there is good evidence to suggest that dreams tend to reflect people's emotional concerns and also things that preoccupy them in their social lives.
Dreams don't just have meaning.
They have been the source of some of the great moments of genius in human history and ultimately have changed the world.
Dreams have been responsible for two Nobel prizes, the invention of a couple of major drugs, other scientific discoveries, several important political events and innumerable novels, films and works of visual art, so they've been very important in our society.
Professor Deirdre Barrett from Harvard Medical School has been studying just how it is that dreams can help us solve problems which we cannot crack in our waking lives.
We can see things much more clearly when we think about them in dreams and it also helps us think outside the box.
Our associations are looser and more intuitive and less linear.
The classic symbol of science, the periodic table of the elements, is said to have come to the Russian chemist Dimitri Mendelay during a dream.
In 1844 American inventor Elias Howe was trying to design his first sewing machine but he couldn't work out how to make it hold the needle.
One night he dreamt of being attacked by savages with spears.
As he woke up in terror, the last thing he saw was that all of their spears had the hole at the pointed tip of the spear and he realised that's where you put the hole in a sewing machine needle.
This extraordinary creativity can even be found in literature.
The story of Frankenstein was dreamt up by Mary Shelley.
This ability to harness dreams and solve problems is not just the preserve of genius.
It seems that many of us can also do it.
Just say to oneself, I want to dream about X tonight as you're drifting off to sleep and in my research I find that about 50% of people can do that if they just practice that for a brief period of time, and about half will get an answer that is really gratifying to whatever the issue is.
But the usefulness of dreams does not just stop there.
It has recently been discovered that we can use our dreams to help us learn in our sleep.
The scientist behind this latest breakthrough is Professor Robert Stickgold.
A dream tells us more in some ways about what's happening in the brain while we're sleeping than any other scientific method we have of investigating it.
Stickgold has devised an experiment that reveals just how dreams affect our learning.
just how dreams affect our learning.
So John here is mostly just having a lot of fun.
He's learning how to play this game, Alpine Racer II, which is a downhill skiing simulator.
He actually controls that character on the screen by moving his feet and he's learning a lot about how to do it, and what we think is that as the brain goes to sleep, it's going to come back to these images.
It's intense.
I'm trying to beat a time and I'm trying to stay in between these gates and it's difficult, but it's a lot of fun.
Once John has gone to sleep, Stickgold wakes him through the night to see how his dreams have changed.
Stickgold found that whilst subjects initially dream about the game, their later dreams draw on other memories.
Please report now.
I was walking through bootprints in the snow.
Some had made bootprints like copying them, going into the ones, stepping into the ones that were already stepped in, like following somebody else's steps along in the snow.
The image that he gets is walking through snow and stepping into the steps that he or someone else had laid down before him, and of course how much easier it is to walk through the snow if you go exactly where you stepped last time.
In these associations, Stickgold perceives a clear link between dreams and memory.
I have this image that what's happening is the brain is not just paying attention to the game but is trying to say, what is that like, what other memories do I have that's like that? And he thinks about moving through snow and I can just imagine the brain trying to say, so when I try to ski this next time, shall I try to do it exactly the way I did it last time? As John takes to the ski game once again, his performance has improved.
I was kind of hitting the wall coming up on this part but I think I can avoid it Yeah.
I think that's pretty good.
And it is this improvement that demonstrates dreams are central to the way we learn.
They know that they are getting better when they play again and in other studies we've evidence that when they dream about it, those people who dream about it actually end up performing better the next time.
So in dreaming, Stickgold believes that we are bringing new experience to bear on old memories, and this is how we learn.
Maybe the most important thing we do with memories is not keep them crystallised the way they happened, but taking them apart and figuring out what's important about what happened to us, and how that relates to everything else that's happened in the past, and figuring out what that means about our future, about what we are going to do tomorrow, a month in the future, a year in the future, how can I use that information.
In some ways, the most brilliant thing that the human brain can do is that kind of extraction and meaning-making.
As we slumber through the dark hours of the night, these visions which haunt our mind are not just random signals in our brain.
They have a purpose.
Science has shown that there is an important connection between our dreams and our memories.
As well as these beneficial traits, we all know that dreams have another side.
It's dark outside, kind of raining, very, very, scary ominous, and it's like this kind of spaceship And an arm with these huge chains with this big stone tablet all inscribed with hieroglyphics A man comes through the back of the wall behind the bed and he comes through the wall like this kind of thing and then he gets a hold of us by my feet and he starts pulling us out of my bed and then I feel as though I'm trying to cling on to the bed and he's saying really horrible things, really scary things.
There is one man who believes these terrifying incidents are good for us, that without them humanity could not survive.
Antti Revonsuo is a Finnish scientist who collects nightmares.
He thinks that many of the bad dreams we have today are the same as those experienced by our ancient ancestors.
Oh, it's pretty certain that our ancestors did dream because dreaming seems to be biologically programmed into our brain, and the brain that our ancestors had was pretty much identical with our brain.
And we know that our ancestors lived in an environment which was full of all sorts of fatal dangers.
What has led Revonsuo to these conclusions is his study of children's nightmares.
There was one wolf and he started chasing me, and I ran and ran and ran, and afterwards, he stopped for a minute and barked, and then another wolf came and another and another and another and then in the end there was a whole pack of wolves with big long teeth and they were very, very hairy and big and scary and they started chasing me.
According to Revonsuo, we have inherited these dreams populated by wild animals and monsters for a reason.
They are rehearsals for the daily struggle to survive.
The nature of bad dreams and nightmares is that they contain threatening events and they force us to go through those simulated threatening events in order that in the waking world we encounter similar or different kinds of threatening events and then we are more prepared to survive those when we have been training for them in our dreams.
This mechanism for rehearsing stressful events will stay with us for all our lives, but as we grow up, dreams about wild animals are replaced by modern horrors.
I was dreaming that I couldn't find the class and then my friend had to come to this class and I couldn't find her either and she couldn't find me and on my way to the class, the elevator, you know, I opened the elevator the door of the elevator and I hit a little girl and she died.
Adults have very modern types of nightmares and bad dreams like losing your wallet, crashing you car or something like that so it seems our brain is capable of adjusting itself and including more modern threats.
Although we may dread our nightmares, they actually help us deal with the day ahead, and as a species, we should be thankful for these fearsome visions.
Bad dreams and nightmares are a good thing.
They force us to be prepared for similar events in the waking world.
Without nightmares and bad dreams there is a good chance that humanity wouldn't be here.
But for some, the reoccurrence of nightmares, far from helping us to survive in the waking world, has exactly the opposite effect.
There are people who suffer an experience so dreadful that it reappears in their dreams again and again.
The one nightmare I had regularly when I came back from hospital was I'd be trapped, like I was in hospital.
I'd feel like my arms would be like this, my legs would be like that.
I couldn't move, I couldn't move any thing and I couldn't speak and he'd always come, be at the side.
Sarah Michael's nightmares were caused by events in her waking life.
They started after the relationship with her then-partner broke down spectacularly.
And I was just sitting there, and he could be really normal and then just flip like that and just suddenly, he just got up and stood over me and he just went whack! Right into, right into here and and just like, it's very difficult to remember the exact way that he did it.
I just remember this great big looming person over me and remember the baby was there, the baby started crying and then the first impact I felt something crack, and I knew immediately something was wrong but I didn't know what and I screamed in pain and fell onto the floor.
The next day she collapsed in agony and was rushed to hospital.
There, doctors diagnosed broken ribs and a ruptured spleen.
Her then-partner came to see her in Intensive Care.
That was really scary as well because he was trying to make out that it wasn't as bad as it was, so he was telling me that he loved me and he didn't mean it but then he would swap and change and say it was my fault because that's what he did, he confused me.
When we are traumatised by an event, the memory is stored in the part of the brain which deals with raw emotion, the amygdala.
The memory is frozen there and replayed again and again.
This is what happened to Sarah so her dreams, rather than processing and resolving her memories, only served to reinforce them.
With every nightmare the traumatic memories became worse and worse until they reappeared in her waking life as well.
Driving, I'd look in my rear view mirror and I'd think he's behind me, in the car behind me but I knew it couldn't be him but my mind was telling me that it was him, even though I knew that he couldn't and literally I had to stop my car and I'd have to park up because I couldn't breathe.
I thought if I can't breathe, I'm going to crash.
Eventually Sarah became imprisoned by her dreams, too afraid to leave the house.
I convinced myself that I was mad.
I felt mad.
Everything that I took, cos I wasn't sleeping, and I went to my doctor and I said, "I'm mad.
" After three years of terror, Sarah was finally diagnosed with Post Traumatic Stress Syndrome.
Following many months of counselling, she was released from her nightmares.
The more I talked about it, the less power it had to frighten me so we'd talk about it quite a lot but it didn't seem so scary.
Once we did all the talking it wasn't so powerful and each time if felt safer and safer like I could tell you now and only I don't feel upset and my hands aren't sweaty, I don't feel traumatised.
It just seems something that happened and it's not happening any more.
It's been, it's gone, it's finished.
Sarah's story shows that the power of the mind can be harnessed to overcome even the most debilitating of dreams.
It appears that there is a fine line between dreaming and being awake.
What keeps them apart is the degree to which the outside world impinges on our consciousness.
The relationship between dreams and consciousness is I think we could actually say that we are dreaming all of the time.
It's just that during wakefulness our dreams are shaped by stimulus information that's coming through our senses, whereas during dreaming, the same consciousness within our brains is not shaped by any external information but it's generated internally.
So I think that life is a dream which is guided by the senses.
When awake, we appear to have control over our conscious state but there are a rare few who can extend control of their consciousness into their sleep and bring the worlds of dreams and wakefulness together.
These people are called lucid dreamers.
For one controversial scientist, an episode of lucid dreaming was so powerful it changed the course of his life.
His name is Stephen LaBerge.
I had a couple of lucid dreams where you know just spontaneously I had, "ah this is a dream and this is interesting, "I want to learn more about it.
" I started reading books about it and found out in the late '70s that most experts in sleep research and dreaming thought that lucid dreams were impossible.
LaBerge set about proving the experts wrong and devised an ingenious experiment to do so.
Before his subjects went to sleep, LaBerge gave them a simple instruction - if they became aware of a flashing light during their dream they were to move their eyes, first left and then right.
Then as they dreamt, LaBerge shone a light in their eyes.
Remarkably the dreamer responded.
A person could simply look to the left and look to the right, and left to right, and that would be a pre-agreed upon signal and so indeed that turned out to be possible.
Having demonstrated that lucid dreaming was possible, LaBerge left the world of science behind.
Nowadays on the big island of Hawaii, LaBerge gathers groups of people for lucid dreaming workshops and he uses a technique which draws on his early experiments.
The students are given a mask with a flashing light.
If they can learn to respond to this whilst asleep, then they are lucid dreamers.
LaBerge wants his students to go one step further by learning how to become self-aware during their dreams.
So one of the best dream signs is not even what you are seeing or feeling out in the inner dream world.
It's reflecting on your thoughts of what's going through my mind right now.
And asking the question would this happen in real life? If my count of limbs multiplies, I know I'm dreaming cos they don't usually just reproduce like that OK? Most people are here to explore the amazing world of dreams and for some, LaBerge believes it has a more serious use.
Facing and overcoming nightmares is I think one of the most important applications.
For people with nightmares, it's learning to understand what they are, they stop frightening you and it's a very compelling powerful tool for personal integration, I believe.
For Justin it's the hope of overcoming nightmares that has brought him to the island.
Well, I'm basically hoping to develop my ability to have lucid dreaming.
I am a recovering alcoholic and I'm bothered a lot of times by dreams about drinking and anxiety, and those are very disturbing kinds of dreams and I would really like to be able to gain control over those and work through it in my sleep so that when I am awake I can help myself to reduce my thoughts about alcohol.
That night Justin, helped by the flashing lights of the facemask, goes to bed determined to take control of his dream.
In the morning, he reports to the group.
I was having sex and I saw a flash of light off to the side and I saw someone taking photographs.
My first thought was I've got to get the camera and I chased him.
In this scenario, LaBerge sees the first signs of lucidity.
The camera represents the flashing light.
Next time I'm having sex and lights are flashing I'll just say hey does this usually happen? LAUGHTER Over the next few nights Justin hones his skills until he finally has his first lucid dream.
It was one of the most exciting things that has ever happened to me.
I was asleep and suddenly I realised I was awake, and I just had a flood of excitement and ecstasy and was aware that I was dreaming even though I was in the bed and I was able to do incredible things.
I stretched my arms really far and I drew a door in the air with a pencil and then became so excited, I woke up.
Taking control of our dream lives is an ability from which LaBerge believes we can all benefit.
It seems to me that lucid dreaming is a skill that ought to be taught in grammar school where it's just hey here's something you can do.
It's a place you can experiment with your life without worrying about consequences.
So science is finding our dreams are many things.
A crucial evolutionary device developed by our minds to help us consolidate our memories.
A way to solve our problems.
Dreams even help us to survive.
Throughout the long night, our mind is training us to face the coming day.
The important thing is just to go through the training and then we get all the training benefits, even if during wakefulness we have no idea we've been training all night.
I think that their value lies in what a different mode of thought they are.
They're so much more intuitive and visual a mode of thinking and in our culture, we spend so much time in this very logical linear mode of thinking that their main benefit lies in presenting such a different point of view to how we usually approach things.
Our brain is working on figuring out the importance and significance of events from our days, how they fit together with old events in our past, what they mean about likely events in the future and if that processing is functional, as I believe it must be, then our dreams are telling us something about what's important to us and the meaning of the events in our lives.
So tonight, as you enter the wonderful world of dreams, lie back and let your mind take you on the adventure of a lifetime.