Other than physiological reasons and observations that sleep helps in memory consolidation, science is not clear about the core purpose of why we sleep and dream. The current research is full of information on frequencies, wavelengths, oxygen levels, heart rate and stages like non-REM and REM sleep and how they cycle in the brain, but does not reveal what the purpose of such processing is and what it intends to do in the brain (cause-and-effect), which is explained below:
Why Do We Sleep? Why Do We Dream?
There are three main requirements for which we sleep and dream, which are 1) Categorization, 2) Distributed Processing and 3) Acausal Story Creation & Processing.
Requirement 1 – Categorization
The evolutionary process has designed our brain to make optimized decisions for its ongoing interactions based on its dynamically changing environments and conditions1.
It stores all incoming information in a systematic way, which enables it to quickly retrieve information connected to ongoing interactions.
To simplify how this happens, I will use the following analogy:
You go to a shop to purchase a t-shirt. You explain the salesman what type of a t-shirt you are looking for. All clothes in the shop are arranged in the racks systematically by their types and sizes. Because of such systematic storage, instead of going through the entire collection of clothes in the shop, the salesman just needs to navigate through the racks using classifications, speeding up the process of fetching the t-shirt of your choice.
In a similar way, our brain stores all incoming information in categories and hierarchies and links them, which helps in speeding up the process of fetching information related to ongoing interactions.
As incoming information gained by our brain is cumulative, the accuracy of categories and hierarchies it is stored in is highly significant. Even a small deviation can snowball into devastating effect on the long run, which is one of the reasons sleep is a must.
As brain is continuously busy processing information2, storing information from such ongoing interactions in precise categories and hierarchies in real-time is not possible. Such processing requires dedicated processing resources, which it does not have.
To accomplish the same, based on the optimizing aspect of the evolutionary process3, the brain allots a particular time for such processing (among other requirements explained below), which is when the conscious part of the brain4, i.e. the self, is switched to internal processing mode. This is when the person is asleep.
In sleep mode, it resumes the process of storing information in precise categories and hierarchies without external disturbances.
To simplify the same, I will use the following analogy:
You are moving to a new house. You have engaged movers and packers to pack and transport your belongings to the new house. They place the items in room wise locations. Once they finish their work and go, you begin placing items in the exact locations where they are supposed to be without any external disturbance.
In the similar manner, information from your daily experiences is stored in general categories and hierarchies in your waking hours. Once you are asleep, i.e. when the self switches to internal processing mode, the process of classification is resumed to store it in precise categories and hierarchies without any external disturbance from the sensory system (except Standby Mechanism).
Requirement 2 – Distributed Processing
Our brain is designed by the evolutionary process to make optimized decisions5, which it achieves by processing them in two ways, direct logic processing and contextual logic processing. The reason why our brain has two hemispheres is so that both of them can be processed separately6.
In detail: Because of its engagement with ever changing environments & conditions coupled with unreliability of perceptions7, our brain makes optimized decisions for our interactions by generating multiple decisions in two ways, 1) based on how to deal with the ongoing interaction using logic (i.e. direct logic processing) and 2) by recalling what knowledge was gained if there were earlier instances of the same or similar interactions and if required, considering what knowledge will be gained by projecting the same or similar interaction in the future (i.e. contextual logic processing), and then judges the best decision out of them to execute8.
As both methods of making decisions are different, they cannot be executed using common processing resources. To deal with them separately, our brain has evolved with two hemispheres.
In majority of population, direct logic processing is handled by the interaction processing area of the left hemisphere, which I’ll call “non-conscious part of the brain” and contextual logic processing is handled by the interaction processing area of the right hemisphere, which I’ll call “conscious part of the brain”9 (the conscious part is where the agency of what we call “self” emerges from).
Following are examples of direct logic processing and contextual logic processing in decision-making:
Direct logic processing of a person on a diet decides to eat the pastry kept in front of him – Contextual logic processing warns him to avoid it for health reasons
- Direct logic processing of a person meeting an acquaintance, based on his sweet talk and body language, takes him as a good friend – Contextual logic processing warns him that he has cheated him in the past
As direct logic processing can 1) pause and resume its progress by saving and retrieving the data that is being processed (as opposed to contextual processing, which cannot do so, as it involves multiple sets of data based on multiple contexts, making it’s storage and retrieval cumbersome) and as it can be 2) driven non-consciously, the brain pauses and resumes such processing when it’s conscious part, i.e. the self, is switched to internal processing mode (same as in the topic of categorization). This is when you are asleep.
In the sleep mode, it resumes such processing by prioritizing parts of interactions it has evaluated as significant (consciously or non-consciously) to reach its goals.
The process of distributed processing is similar to a cow with ruminant digestive system chewing previously consumed food further.
Our daily interactions use a high amount of direct logic processing10, which, as explained above, is distributed between multiple conscious and non-conscious states by pausing and resuming, and thus, is cumulative. If such interactions are not processed in the sleep state due to lack of sleep, the brain’s processing can become highly cumbersome, which is another reason why sleep is a must.
In sleep mode, the contextual logic processor aids direct logic processor’s non-conscious processing as and when necessary, thereby aiding both direct and contextual logic processing. Such processing is the basis of the idiom “sleep on it”.
The result of such processing is also used in the Acausal Story Creation stage, which is explained in the next topic.
As the load of categorization and distributed processing keeps accumulating throughout the waking hours in the daytime, the earlier a person sleeps, the lesser load of information his/her brain has to process, the better it performs. Following such better performance, when the same person wakes up early, his/her brain is more efficient and ready to take on the next day’s interactions, which is the first causal explanation behind the phrase originated in 17th century and was one of the most famous quotes of Benjamin Franklin, “Early to bed and early to rise makes a man healthy, wealthy and wise”. It is also one of the reasons why naps are good.
Requirement 3 – Acausal Story Creation and Processing
As we make decisions based on knowledge we have gained from past experiences and how we project them into the future, it is pretty much fixed what decision we will make given a particular set of circumstances. As can be derived from the same, our decisions are based on causality, i.e. cause-and-effect thinking. E.g. “If I do this, that will happen”, “If he comes, I’ll go with him”, “if my pen breaks, I’ll buy another one”, etc.
With such cause-and-effect thinking, we typically do not consider anything other than what our basic pattern of thinking offers while making decisions.
Based on the idea that we do not always make the best set of decisions to reach our goals, such limitation is a big disadvantage for us, especially as all our critical decision making and problem solving is based on such cause-and-effect thinking. Being habituated with such thinking prevents our mind to be more creative using “out-of-the-box” thinking.
To resolve the same, based on the optimizing aspect of the evolutionary process11, our brain has evolved with the mechanism of dreaming, the primary goal of which is to optimize decision making using acausal thought processes (i.e. thought processes that are not based on cause-and-effect thinking, which is explained in detail later). Such thinking frees our brain from the confines of the perfectly valid, but rigid way of cause-and-effect thinking.
How it works: When you are awake, the non-conscious part of your brain feeds data to the conscious part (the self) from your sensory inputs. The conscious part processes such sensory data using thought processes to form perceptions12 (you use such perceptions to decode contents of your interactions, which help you in deciding on how to deal with them).
When you are asleep, the same non-conscious part of the brain feeds data to the conscious part (which has switched to internal processing mode, as it is in sleep state), but the data it feeds is not from sensory inputs, but is from the memory of past perceptions resulting from processing such sensory inputs using thought processes.
In detail: To fulfil the requirements of acausal thinking mentioned earlier, our brains have evolved with a mechanism over thousands of generations that creates its own acausal stories, i.e. stories that are coherent and grammatically valid, but do not have any causal underpinnings and thus, their content do not have any purpose (other than acausal processing, which is explained below).
Such stories are created using perceptions that were processed in past experiences in four steps, from creating the initial sentence long narration to creating the entire story of the dream, as explained below.
Before understanding the dream creation process, it is important to know the following:
The non-conscious part of the brain stores various types of data connected to concepts in memory locations based on categories in its databank. E.g. data of concepts like residence, cars, animals, teachers, etc. are stored in their respective physical locations (as opposed to storing data based on hierarchy in the conscious part)13
- Dreams work by storing and retrieving perception data, i.e. data stored from past perceptions in the non-conscious part of the brain, which was generated by processing sensory inputs using thought processes by the conscious part of the brain
Four steps of dream creation:
Step 1: The non-conscious part of the brain retrieves perception data of a randomly selected past experience to from a sentence long narration
E.g. Jay went to the market to purchase fruits.
Step 2: Next, it replaces perception data of elements contained in such sentence long narration with perception data of random elements that are grammatically identical in structure along with perception data of concepts contained in it with perception data of randomly selected concepts from their same category in the categorized storage to make a sentence long acausal narration.
E.g.: Roy joined the navy to serve the country.
Another random selection from the same template could have been…
Neha entered the stadium to watch the game of cricket.
Sunil waved towards the car to stop it.
In the above narrations, “Roy”, “Neha” and “Sunil” are cousins and thus, their data is stored under the classification “cousins” in the location where data of all cousins is stored. The same is with other concepts.
Step 3: Next, it searches for a full-length experience whose pattern or summarization matches (remotely, if not closely) the contents of such randomly created sentence.
If it does not find a matching full-length experience, it creates a new one using a pattern or summary of experience ingrained in the memory that either contains unresolved thoughts and emotions or is marked as significant, the reason for which is based on the fact that one pays more attention to a story which is significant or familiar, and attention to the story is important for effective acausal story processing.
Step 4: Next, it replaces perception data of elements contained in such matching experience with perception data of random elements that are grammatically identical in structure along with perception data of concepts contained in such matching experience with perception data of randomly selected concepts from their same or similar category in the categorized storage to create the story of the dream.
Once the story is created, it is fed to the conscious part of the brain (which is in internal processing mode – i.e. in sleep state), which receives it as a dream.
As non-conscious part of the brain is the homeland of dreams, which generates such stories, if there are unresolved thoughts and emotions ingrained in its memory, based on their strength and significance to the self, they may influence – and also be a part of – the narration process, which is the basis of dreams that contain elements from our past
- The reason why some dreams are in metaphoric form is that templates for creating their stories are based on summaries of past experiences (as explained in steps 3 and 4), where concepts contained in such experiences are replaced with data of randomly selected concepts from their same or similar category in the categorized storage in its databank, as explained earlier
Finally, 1) the result of distributed processing stage and 2) unresolved thoughts and emotions ingrained in the memory explained above are processed with the story of the dream to benefit from acausal thought processes.
Following are the reasons why our brain goes through such an elaborate process to create a dream:
The usage of 1) past experiences as templates and 2) concepts & elements that are familiar to the self make the story realistic (in terms of structure, not concepts, as concepts are randomly selected, which is the reason why some dreams are illogical) and thus, acceptable to the conscious part of the brain, which is in internal processing mode
It prevents you from getting into “once upon a time” mode. In other words, it gives the feeling that you’re experiencing the content of the dream, i.e. treating it as an actual experience and not as a story
- It provides an extra stream of thoughts that matches your experiences, but are not based on causality, which helps in both, categorization and distributed processing stages
The above points are the reason why memories get stronger in sleep (memory consolidation), which is seen in sleep studies.
Stages of Sleep
In the sleep state, brain’s processing goes through following four stages:
1) Transition to Light Sleep – which is known as Non-REM sleep stage 1
2) Categorization – which is known as Non-REM sleep stage 2
3) Distributed Processing – which is known as Non-REM sleep stage 3 and
4) Acausal Story Creation & Processing – which is known as REM sleep
Sleep Cycles and their Purposes
Dreams play a significant role in overall sleep processing. As they are created from random elements which are recognizable by the self, the brain cycles through the stages mentioned above repetitively in a specific sequence. Such sequence is based on each stage gaining from previous stage(s) individually, collectively or cumulatively, either in forward or backward succession, in terms of effectively creating and processing the acausal story with the results of distributed processing and categorization stages, additional to effectively processing the same with unresolved thoughts and emotions (if any), until the point there is no gain received from previous stage(s).
The following example simplifies the above explanation:
More accurate categorization leads to improved distributed processing, which leads to further improved categorization, which leads to further improved distributed processing, which leads to improved acausal processing, which leads to further improved categorization, and so on, until the point there is no significant gain received from the previous stage(s).
Besides gaining from previous stages, the other reason why sleep stages are divided is that based on the idea that as each of them are equally important for the overall sleep processing (as I have explained earlier), if for some reason the sleep period is curtailed, e.g., if a person sleeps for shorter period, each stage is curtailed proportionately.
Once the brain enters sleep state, a standby mechanism is activated. In the standby mode, the non-conscious part of the brain keeps a watch on sensory inputs based on a threshold (more about threshold below). If any sensory input crosses such threshold, it alerts the conscious part of the brain (i.e. the self), which is in internal processing mode, causing it to switch to general processing mode (i.e. waking state).
Although one can change such threshold to some degree using the conscious part, it is chiefly set by the non-conscious part of the brain (often dynamically) and differs from person to person, which is the reason some people can be more easily awakened than others.
As can be derived from the dream creation process, the non-conscious part of the brain creates a grammatically valid and coherent story which is free of cause-and-effect thinking out of elements that are randomly selected from the memory and thus, is not intentional, which is the reason why in reality, many of our dreams contain elements known to us (including those that hold no significance to us), but are not intended to mean anything to us
As can be derived from dream creation process, there is no scarcity of memory storage space in the human brain. Memories are never erased. They just become less accessible. When you say you forgot something, it only means that it has become less accessible to you. The same is due to availability of enormous information storage space in the DNA made possible by combinations of base molecules
Although some dreams are influenced by thoughts and emotions ingrained in the memory based on their strength and significance to the self, they just “come for a ride” and are not created for mental or emotional fulfilment. Such dreams only reveal thoughts and emotions that are ingrained in the memory
Negative dreams do not indicate that a person has a negative mind, unless they occur on a regular basis, which, based on the reasoning given earlier, demonstrates that such a person has negative thoughts and emotions ingrained in his/her brain (the same goes for positive entities like objects of desire which are ingrained in the brain, e.g. a girl/guy of one’s dreams)
Some dreaming also occurs in distributed processing stage, but as it is based on recalling data of distributed processing, which is fragmental, there is no story or visual imagery attached to it (the way it is in REM sleep), which is confirmed by sleep studies. The same is also responsible for abrupt awakenings, nightmares, etc.
Repetitive usage of acausal thinking aids “what-if”, “if-then-else”, etc. type of thinking, which aids creativity. If there were no mechanism of dreaming, it would not be easy (the way it currently is) for a person to think in a pattern other than cause and effect thinking
- As the sole purpose of dreams is to benefit from acausal thinking, which is fulfilled in the sleep state, no effort is done by the brain to memorize them
Note: This post sufficiently explains the logic behind mechanisms related to sleep and dreams. Please follow the links given below only when you want to dig deeper into the subject.
(Source – Mechanisms of the Mind by Parag Jasani)
1 Optimizing Aspect of the Evolutionary Process – page 3
2 Intramural & Extramural Communication – The Origin of Thought Process – page 36
3 Optimizing Aspect of the Evolutionary Process – page 3
4 Virtual Person (VP) – ‘Contextual Logical Processor’ – page 20
5 Human Brain is Designed to Make Decisions – page 181
6 Why do We Have Two Hemispheres? – page 182
7 Factors related to Perception – page 8
8 The Thought Process – Step-By-Step – page 47
9 Illustration – Dichotomizing Operating System – page 18
10 LB Monologue – page 36
11 Optimizing Aspect of the Evolutionary Process – page 3
12 Perception – page 77
13 Illustration – Dichotomizing Operating System – page 18
14 Reason for Hard-Wiring – page 96