What do dreams do? - Sue LlewellynWhat do dreams do?“, if asked, I expect many people would say “Not much!” This book offers a completely different picture. I think, way back in evolutionary time, we dreamed to survive. So we should take our dreams seriously! For some taking dreams seriously is about working out what they mean. I think we can do this through identifying their links to our memories. So we shouldn’t dismiss our dreams but we don’t need to puzzle over what our dreams mean to gain from them. Most dream-work happens unconsciously. Our dreams influence our decisions, expectations and actions, they also enable us to remember. All of this happens without us realising it! Being in a dream-like state of mind makes us more creative, which can merge into craziness.  Dreams do lots of things. This book tells you how.

To start to explore the mystery of dreaming, Chapter 2 of my book argues a dream is a pattern in your experience but you haven’t actually experienced this pattern. This sounds odd but then dreams are weird, aren’t they…


What is a dream? I think a dream identifies a complex pattern in experience and portrays this in a dream image. In other words, I argue for a complex pattern identification theory of dreaming. We can detect complex patterns in wake too, but our thought is convergent and driven by more obvious associations. Whereas, during dreaming, we see less obvious associations because we think in a divergent way. This Chapter covers why, in our evolutionary past, we needed to detect complex, non-obvious, divergent patterns and begins to explain why the dreaming state evolved to do this. I think complex pattern identification occurs during Rapid Eye Movement (REM) sleep, with the pattern visualised in a REM dream.

We have broadly two types of dreams, REM and NREM. Unsurprisingly these two sorts of dream occur in two different sleep stages: REM and non-rapid eye movement (NREM). REM dreams are those mental experiences which we think of as dreams. They are vivid, bizarre, emotional, highly associative mental experiences which develop in a story-like manner during sleep and are embodied, but out of our control. Whereas NREM dreams are more thought-like, less vivid, less emotional and less story-like. This chapter concentrates on REM dreams.

Keywords: Patterns; visual; probabilistic; divergent; non-obvious; Rapid eye movement (REM).


Dreams are a puzzle. We don’t know what to make of them. Familiar faces, identifiable places and remembered experiences appear but dreams mix them up. Why? This book aims to convince you that dreams take people, places and events out of their waking life context to identify a complex pattern in your experience. But dreams don’t seem like complex pattern identifiers. They appear chaotic. To address this apparent paradox, we’ll take a detour into pattern detection.

Discerning patterns in the world

Your brain evolved to detect patterns. My definition of pattern is: a discernible form in the way something happens or is done, where this form can be visualized. My theory is rooted in our pre-linguistic evolutionary past. Across evolutionary time, a pattern is something detectable in the way humans and animals behave as they move about to secure resources (food, water, mating opportunities) in the world. Contemporarily, “resources” encompasses much more than this because we do more than meet our basic needs.

We humans share our visual pattern-recognition ability with animals. As we experience the world we see patterns: the pattern of features which make up a face; a pattern of food locations; and a pattern of gestures which communicates information[i]. Expert human skills depend on remarkable pattern detection: playing chess; diagnosing illness; scientific discovery; military strategy; and mathematical relationships. Some argue all brain functions depend on recognizing patterns in experiences[ii]. I agree with this. We have dream experiences as well as waking ones. If dreams have a function is this visual pattern detection too?

What is a visual pattern anyway? Perhaps you are thinking of those red check tablecloths, which used to feature in Italian restaurants. These are patterned by design and the visual check pattern is immediately obvious-requiring no detection skills. But simple detection skills are necessary to answer the question of whether all Italian restaurants have red check tablecloths. In other words, do red check tablecloths repeat over time and place in Italian restaurants?  There used to be a cultural pattern (how things are done) that linked red checkered tablecloths and Italian restaurants- they went together in time and space.

Red checkered tablecloths were associated with Italian restaurants 

So back in the 1980s if you went to an Italian restaurant you expected a red checkered tablecloth. In this book we are concerned with discernible patterns which happen in nature and can be seen rather than cultural patterns about the way things are done. These natural patterns aren’t designed but they do often repeat in space and time. Two eyes, a nose and a mouth in the same spatial arrangement is the pattern we look for in a face.

A human face pattern

This pattern also repeats in time, so whenever we see two eyes placed symmetrically over a nose and mouth, we recognise a face. Faces also repeat in space. Many different creatures in many different places have faces.

An elephant’s face is different but we still recognise the face pattern

But not all faces look alike- an elephant’s face is very different from a human one.

Is this a face or is the person faceless?

It’s hard to say. The “face” looks sufficiently different to be worrying, probably we would decide it’s a person wearing a mask. We aren’t  looking directly at a face. So it makes sense to talk of discerning the pattern which makes up a face, whereas it doesn’t make sense to speak of detecting the pattern of a red checkered tablecloth- the pattern is obvious.

Identifying complex, non-obvious activity patterns in the world

On seeing a face, we know we are in the presence of another living being which moves about. The behaviour of living beings, their activity patterns, as they move about to secure essential resources like food and water, isn’t obvious. For any living being, it’s a complex non-obvious pattern which has to be detected. I propose dreams evolved to detect these complex non-obvious activity patterns. By complex and non-obvious, I mean that the elements of the activity pattern are associated in a complicated way. Complexity also comes about because the elements of the pattern may not appear together in time. We recognise a face whenever the same elements (eyes, nose and mouth) appear together- at the same time. But not all patterns are like this. The elements of the pattern, which predict when another living being will be at a certain place, may never all appear together in time.

Suppose there’s another academic, called Len, and, like me, he’s based at the university but often works at home. Len is a bit of a pest, so I’m trying to avoid him. Without asking him, I’m trying to identify his “being in the university” pattern through visual observation. I’ve seen him there if he has an important meeting or if he has to teach a class.  Len also attends university graduation ceremonies. Len usually picks his kids up from school but I’ve observed him working late in his office when his partner, Liz or her mother, Lorna, picks them up and drives them home. Len lives near the university. When his fridge is empty, I’ve seen him sometimes eating in the university café. Individually, these patterned elements repeat over time, for example, Len is repeatedly at the university when he is teaching. And he’s a regular attendee at university graduations. But the different patterned elements appear at different times, they don’t usually all come together at the same time. It’s highly unlikely Len would be in the university for a meeting and to teach a class and because there is a graduation ceremony and because his partner or his mother-in-law is picking up the kids and because he’s eating in the café. But we don’t always detect patterns to avoid people. If Len was attractive I could observe this same pattern and use it to be at the university at the same time as him.

In evolutionary terms, why would we need to detect a complex pattern which predicts “a living creature being at a particular place”? Like animals, we can recall a pattern of food locations. So far so good, but across evolutionary time, it would have been much safer to visit dependable food and water sources at times when predators and competitors tended to be absent. Visiting a waterhole with a lion present- in clear view- wouldn’t be a good idea.

Predator at the waterhole

A much better plan would have been to visit when there were no predators or competitors but potential mates were around. But how to know? Observation of their past patterns of behaviour, in visiting places with desirable resources, like the waterhole, would have been the only way. For example, the general pattern of lion behaviour is to hunt at night. So usually it will be safer to visit the waterhole during the day. But lions do sometimes visit in the daytime-particularly in the dry season when they get very thirsty and when prey like zebra and wildebeests are around. So time of day, seasonality, thirstiness and availability of prey are elements in the pattern.

Visiting at night, when the waterhole is surrounded by dense vegetation which affords ambush cover for predators and when prey animals are present is very dangerous. Picturing a waterhole at night in the dry season surrounded by thick reed beds, with zebra and wildebeests should induce fear because it signals danger. If you were to picture a relatively, safe time to visit the waterhole you would visualize the daytime in the wet season with no zebra and wildebeests. Being able to imagine these scenes doesn’t mean you have actually experienced them. You probably have not. For example, you may have glimpsed a lion hiding in thick reeds beds around the waterhole during the day in the dry season. Equally, you may have seen a lion drinking from the waterhole at night on a few occasions. Also you may have seen lions kill and eat zebra and wildebeests at the waterhole. Elements of lion- related experiences which happened at different times but at the same place are associated in the picture, in effect the pattern, because all are indications which predict the presence (or absence) of a lion at the waterhole.

But sometimes there would have been elements in the pattern which predicts “lion at the waterhole” which happened away from the waterhole. For example, you saw elephants gathering near a clump of trees. When some lions appeared the elephants chased them away. This didn’t happen at the waterhole. It happened at a different place- at the clump of trees. But from an “away for the waterhole” experience you inferred that elephants may chase lions away from the waterhole too. Similarly, for the “pest at the university” pattern, when Liz or Lorna pick the kids up from school, you inferred that Len is more likely to be at the university. But picking the kids up from school doesn’t happen at the university- it happens at the school gate.

Probabilistic patterns and hybrids

Like the “pest at the university” pattern, “the lion at the waterhole” activity pattern is only probabilistic- meaning that the pattern is made up of tendencies rather than certainties. Len often stays late at the university when his partner or her mother picks up the kids but if he gets fed up during the day he may go home at five o-clock anyway. Lions tend to visit the waterhole at night but they sometimes visit during the day. Their daytime visits tend to be in the dry season when they tend to be thirsty. We are dealing with probabilities or, in less technical language, tendencies. There are no dead certs when it comes to animal or human behaviour. Their behaviour isn’t random but it’s not deterministic- like day follows night.

When detecting complex patterns in past experiences, elements, which have the same significance, may be combined to make a hybrid. What do we mean by elements with the same significance? In the “pest at the university” pattern, Len’s partner, Liz, or her mother, Lorna, may pick up the kids. So far as the pattern is concerned his partner and mother-in-law are both patterned elements which have the same significance. So Liz and Lorna may be combined to make a hybrid Liz-Lorna person.

Dreams portray complex patterns in your experience

I propose we portray complex, non-obvious, probabilistic, divergent patterns in our experiences through the visual medium of dreams. In a nutshell, this is what dreams do. Dreams are complex non-obvious patterns derived from our experiences. But these patterns have not usually been experienced. They associate elements from different experiences. So, we may say that dream construction doesn’t only recognize patterns; it searches for and discovers patterns or even creates patterns. The liena is a patterned element I created through associating a lion and a hyena but a liena doesn’t actually exist. The evolutionary imperative to obtain food and water and meet with mates whilst avoiding predators and competitors may have driven us to imagine the impossible in our dreams!

For example, returning to me working out when Len, the pest, will be at the university, if I dream the pattern which predicts this, it may go something like this:

Scene 1

I am at a university in a large room. I can see Len. He seems to be teaching a class but there are some of our colleagues sitting around a table- as if he is in a meeting.

Scene 2

Suddenly Liz, Len’s wife appears, she walks up to a very large open gate in the wall of the room that Len is in. By the gate are two young children. Liz takes them away.

Scene 3

I can see Liz, or it may be her mother, Lorna, she is dressed like Liz but has the same hair as Lorna, she is sitting on the top of an empty, very small white car with doors like a fridge. But somehow Liz/Lorna is driving along. The car has lots of stickers on it- they look like fridge magnets.

Scene 4

Liz/Lorna drives past the university café. Through the café window I can see Len. He is dressed in a university gown and eating a sandwich.  

These four scenes are formed by combining the individual elements of the pattern which predicts when Len will be at the university. This associative process mixes up people, places and events because it extracts them from their various real life contexts to portray the “Len, the pest, at the university” pattern. These combined patterned elements are then cast into a narrative.

A story structure seems to be the basic way that the brain organizes experience, we cast our experiences into narratives whether awake or dreaming[iv]. This condensed dream narrative engenders bizarreness, even impossibilities: the wall of the university room has a gate (this gate represents the school gate from where Liz/Lorna picks up the kids); the fridge-car cannot take passengers, it can only be driven by sitting on top of it because it is so small, it is empty because the fridge has no food in it; Len is wearing a university gown (now only worn by UK academics for graduation ceremonies) while eating a sandwich in a café.

This narrative creates new people, objects and events. A new person is produced through merging Liz and her mother Lorna – from the point of view of the pattern they have the same significance because they both sometimes pick the kids up from school. The new object is the small, white, empty fridge-car. When the fridge is empty, Len sometimes eats at the café in the university. Equally, when Liz/Lorna picks the kids up from school she drives them home and Len is more likely to be in the university. The fridge and the car may be merged into one object because they are associated, they share some characteristics: both are containers, one for food the other for people; both are metallic; white is a common colour for both; and now we have such large fridges and such small smart cars their sizes are not so dissimilar; and we humans decorate both our fridges, with magnets and our cars, with personalised number plates and window stickers with messages such as “Baby on Board”. A car and a fridge aren’t obviously associated but, in several non-obvious ways, they are.

The last Chapter distinguished REM from NREM dreams. REM dreams are organized into narratives which are more associative and more bizarre than NREM dreams. I think complex pattern identification happens during REM sleep with the pattern portrayed in a REM dream.

What’s the difference between the complex patterns we detect in wake and those we see in dreams?

Surely our brains, when awake, are smarter than our dreaming brains so why can’t we identify complex patterns while awake? Of course, as noted above, we can, think of playing chess or diagnosing illness, but the type of complex patterns we can detect in wake differ. I don’t think you can say we are smarter in wake than in dreams or vice versa, just that our brains work differently. Consider the contrasts between the patterned associations we make in wake and those we see during REM dreaming. See Diagram 1 below.

Diagram 1: Contrasting associative patterns in wake (left) and REM dreaming (right)

Adapted from: p 70 in Hartmann, E. (2011) The Nature and Functions of Dreaming, UK: Oxford University Press

In wake we use sequentially directed logic to detect patterns and our thinking converges on an output. For example, if shown this ☺ we recognise “It’s a face”, we make a definite judgment, even though the nose is missing. This definitive output reflects our thinking in wake, we may be wrong about what we see but we don’t see two things at once. In REM dreams we tolerate ambiguity, which creates bizarreness. For example, in Scene 1 of the Len scenario/dream above, Len could be teaching or he could be at a meeting- somehow he is involved in both simultaneously. In Scene 2 I see a person who may be Liz but at the same time is also Lorna. In wake, our thinking is convergent on an output. In contrast, in REM dreams, we make divergent associations, our associational nets spread out.

During wake, our pattern detection is constrained by logic so if I saw a liena I would deduce I was hallucinating. Whereas, unconstrained by logic in dreams, I have no problem in seeing a visual pattern which looks a bit like a lion and a bit like a hyena. As discussed above, these differences are linked to the presence of hybrids and probabilistic associations in dreams.

Overall, the differing modes of perception in wake and dreaming result in better detection of patterns driven by logic, obvious associations and sequencing during wake. Whereas, during dreaming, we excel at discerning divergent patterns underpinned by non-obvious associations. In the following Chapters we will look more closely at the differences between wake and dreaming in terms of pattern identification and association but, for the moment, we characterize dreams as identifying complex, divergent, non-obvious patterns.

You may buy this idea of dreams discerning complex, divergent, non-obvious patterns but you may be thinking dreams are forgotten so how can they be used during our waking lives? Do dreams come from the unconscious? If the evolutionary purpose of dreams was to avoid predators and competitors while meeting mates, are dreams of any use now? The rest of the book addresses such questions.


In answer to the question: What is a dream? I propose: REM dreams portray complex, divergent, non-obvious patterns in past experiences but not patterns which have actually been experienced. If this sounds peculiar, well, dreams are strange- at least to our minds in wake. To create a pattern which hasn’t been experienced you take associated elements of past experiences and put them together to make something new- as I did above in the “pest at the university” example.

The evolutionary driver for discerning such patterns was, archetypically, to avoid meeting predators at places you wanted to go- like food sites and waterholes. To evade a predator at a waterhole you needed to work out what circumstances increased the probability of a waterhole visit and then associate them. Things like: night-time; when there is dense vegetation to provide ambush cover around the waterhole; when the predator is thirsty; when it’s hot; when elephants aren’t there; and when prey animals are there.  If you could avoid being eaten you stood a chance of reproducing. To meet a potential mate also required observation of their activity pattern to work out when and where a safe encounter was likely.

[i] Mattson, M. P. (2014). Superior pattern processing is the essence of the evolved human brain. Frontiers in neuroscience, 8, 265.

[ii] Fukushima, K., & Miyake, S. (1982). Neocognitron: A self-organizing neural network model for a mechanism of visual pattern recognition. In Competition and cooperation in neural nets (pp. 267-285). Springer, Berlin, Heidelberg, Chapter 3 in Kurzweil, R. (2013). How to create a mind: The secret of human thought revealed. Penguin, Humans are the world’s best pattern recognition machines, but for how long? Available at:  and Does the human brain work solely by pattern recognition? Available at:

[iii] The predator chain Botswana wildlife guide. Available at:

[iv] Pace-Schott, E. F. (2013). Dreaming as a story-telling instinct. Frontiers in psychology, 4, 159.