Why do we Sleep and Dream?

Why do we Sleep and Dream?

The mystery of sleep and dream revealed. 

By Parag Jasani o www.YourDailyLife.blog
Updated on

Even when they consume one third of our lifetime, sleeping and dreaming are among the biggest mysteries of mankind.

Current research on the topic is full of data like frequencies, wavelengths, oxygen levels, heart rates, etc. What it does not explain is the reason why we sleep and dream, which is revealed in the following explanation:

There are three core reasons why we sleep and dream, which are 1) Categorization, 2) Distributed Processing and 3) Acausal Story Creation & Processing. Following is their explanation in detail…

Reason 1 – Categorization

The optimizing aspect of natural selection has designed our brain to make optimized decisions for its ongoing interactions based on its dynamically changing environments and conditions.

It stores all incoming information in a systematic manner, which enables it to quickly retrieve information connected to our ongoing interactions, thereby helping in making decisions on how to deal with them.

The T-shirt analogy explained in the post Understanding Awareness simplifies how it happens, which is as follows:

You go to a shop to purchase a t-shirt. You explain to the salesperson what type of 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 salesperson 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 systematically and links them to what I call “awareness buffer”.

While interacting, it navigates through a web of links to search for information and summaries stored in the memory that are related to such ongoing interactions in multiple ways (all of which is explained in detail in the post How Does Our Mind Develop). Doing so helps in drastically speeding up the process of fetching information related to ongoing interactions.

As information gained by our brain keeps accumulating on an ongoing basis, the accuracy of categories and hierarchies where it is stored becomes more and more significant for its efficient execution. Even a small deviation can snowball into devastating effect on the long run, which is one of the reasons sleeping is a must.

As the brain is always busy processing information, storing information from such ongoing interactions in precise categories and hierarchies in real-time is not possible. Such processing requires dedicated processing resources.

To accomplish the same, the brain allots a particular time for such processing, which is when system 2, i.e., the self, switches to internal processing mode. This is when the person goes to sleep.

In sleep mode, it resumes the process of storing information in precise categories and hierarchies without external disturbances.

To make it simple, 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. In the new house, they place the items in room-wise locations. Once they finish their work and leave, you begin placing each item in the exact location-where it is supposed to be without any external disturbance.

In a similar manner, information from your daily interactions is stored in general categories and hierarchies in your waking hours. Once you are asleep, that is, when your system 2 goes into standby mode and switches to internal processing, the process of classification is resumed to store it in precise categories and hierarchies without external disturbance from the sensory system.

Reason 2 – Distributed Processing

As explained in the article How Mind Emerges from the Brain, our brain is designed by the evolutionary process to make optimized decisions, which it achieves by processing them in two ways, direct logic processing and contextual logic processing. As both are different, they cannot be processed using common processing resources. The reason our brains have evolved with two hemispheres is to enable them to be processed separately.

Following are examples of both of them:

  • Direct logic processing of a person on a diet makes the decision to eat the cake 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 to be careful, as he has cheated him in the past

As it is possible for direct logic processing to 1) pause and resume its processing by saving and retrieving the data it is processing and as it can be 2) driven non-consciously, system 1 resumes processing it in the sleep state without any disturbance from the conscious system 2, i.e., the self, as that is when it is switched to internal processing mode. 

In the sleep mode, it resumes such processing by prioritizing parts of interactions it has evaluated as significant, either consciously or non-consciously, to reach its goals.

Our daily interactions use a high amount of direct logic processing, which, as explained earlier, is distributed between multiple sleep and awake 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 sleeping is a must.

In sleep mode, the contextual logic processing of system 2, which is in internal mode, helps system one’s direct logic processing as-and-when necessary, thereby aiding both direct and contextual logic processing. Such processing is the basis of the idiom sleep on it. An example of the same is when we say, ”It is a tough decision, I’ll let you know tomorrow, let me sleep over 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 goes to sleep, the lesser load of information his brain has to process, the better it performs.

Following such better performance, when he wakes up early, his brain is more efficient and ready to take on the next day’s interactions. The same is the first causal explanation behind Benjamin Franklin’s popular quote, “Early to bed and early to rise makes a man healthy, wealthy and wise”. It is also the reason why many of us feel fresh on waking up in the morning.

Categorization and distributed processing stages are the reasons why memories get stronger in sleep, which is known as memory consolidation in sleep studies.

Reason 3 – Acausal Story Creation and Processing

As we make decisions based on the knowledge we have gained from past interactions 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 a new one”, etc.

With such cause-and-effect thinking, we typically do not consider anything other than what such basic pattern of thinking offers while making decisions.

Based on the idea that nobody is perfect enough to claim that they always make the best set of decisions to reach their 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 creative using “out-of-the-box” thinking.

The optimizing aspect of natural selection has designed the mechanism of dreaming to resolve such limitation. The primary goal of the mechanism of dreaming is to optimize the decision making process using acausal thought processes, which are thought processes that are not generated by cause-and-effect thinking. Such thinking frees our brain from the confines of the perfectly valid, but rigid way of cause-and-effect thinking, which is reflected in the quote by Albert Einstein, “I never made one of my discoveries through the process of rational thinking”.

How the dreaming mechanism works:

When you are awake, your system 1 processes sensory data from your ongoing interactions. If preset data for perceptions is found hard-wired for such data in system 1, it converts them into perceptions, which, along with rest of the sensory data, i.e., sensations, are fed to your system 2. Your system 2 uses such sensations and perceptions to decode the contents of your interactions, which help you in deciding on how to deal with them.

When you are In the Acausal Story Creation and Processing stage of sleep, the same system 1 feeds data to your system 2, which is when it is switched to internal processing mode, but the data it feeds is not from sensory inputs, but from the memory of past sensations and perceptions resulting from processing such sensory inputs using thought processes. Following is the detailed description of the same:

To fulfil the requirements of acausal thinking mentioned earlier, the brain has evolved 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 basis and thus, their content does not have any purpose or meaning.

Before understanding the dream creation process, it is important to know the following:

  • System 2 links hierarchically stored concepts from its database to memory locations in system 1’s databank based on their categories. For example, data of concepts like your residence, cars, pets, teachers, etc. are linked to their respective physical locations in system 1. Such arrangement makes it possible for both systems to navigate either by category or by hierarchy, as and when required.
  • Dreams work by system 1 projecting sensation and perception data associated to the story to system 2.

The process of creating the initial sentence long narration to creating the entire story of the dream happens in four steps, which are as follows:

Step 1 – Random Root Sentence Retrieval: System 1 retrieves data of a randomly selected past interaction from the memory to form a sentence long narration.

E.g. Jay went to the market to purchase fruits.

Step 2, Acausal Sentence Creation. Next, it replaces concepts contained in the sentence long narration with randomly selected concepts from their same categories in the categorized storage of links in system 1. It also replaces data of other elements contained in the narration with data of random elements that are grammatically identical in structure. Both are then used to make a sentence long acausal narration.

E.g. Roy joined the navy to serve the country.

Other random selections 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 such narrations, “Roy”, “Neha” and “Sunil” are cousins and thus, their data is linked to the classification “cousins” in the location in system 1 where data of all cousins is stored. The same is with other concepts.

Step 3 – Root Story Creation: Next, it searches for a full-length interaction whose pattern or summarization matches (remotely, if not closely) the content of such randomly created sentence, e.g., the one where Neha enters the stadium to watch the game of cricket.

If it does not find a matching full-length experience, it creates a new one using a pattern or summary based on unresolved thoughts and emotions that are ingrained in the memory and are marked as significant.

Step 4, Final Story Creation. Next, it replaces concepts contained in such matching experience with randomly selected concepts from their respective categories linked to system 1. It also replaces data of elements contained in such matching experience with data of randomly selected elements that are grammatically identical in structure. Both are then used by system 1 to create the story of the dream.

Once the story is created, the sensation and perception data associated to the concepts and elements of the story is retrieved and fed to system 2 (which is in internal processing mode, i.e. in sleep state), which receives it as a dream.

  • As system 1 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 people and elements known to us
  • The reason why some dreams are in metaphoric form is based on the fact that templates for creating their stories are based on summaries of past experiences (as explained in steps 3 and 4). They get metaphoric form as concepts and elements contained in such experiences are replaced by system 1 with randomly selected concepts and elements that are linked to same or similar category in the categorized storage in its databank, as explained earlier
  • Even though dreams are generated by system 1, which uses direct logic processing, the reason why many of them do not seem to be logical is that system 2 is in internal processing mode, that is, in sleep state and thus, is unable to correct them using contextual logic, the way we do when we are awake

Finally, the acausal story of the dream is processed with 1) the result of the distributed processing stage and 2) unresolved thoughts and emotions ingrained in the memory, as explained earlier, and utilized if beneficial.

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 and other elements that are familiar to the self make the story realistic and comprehensible to system 2, which is in internal processing mode
  • Usage of sensation and perception data associated to feed the story 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 being told to you
  • It provides an extra stream of thoughts that match your experiences, but are not based on causation, which helps in both, categorization and distributed processing stages

Stages of Sleep

In the sleep state, processing in the brain goes through what is known as Non-REM and REM sleep stages (where REM stands for Rapid Eye Movement, which is a stage in sleep when eyes move rapidly), as follows:

1) Non-REM sleep stage 1 – which is Transition to Light Sleep

2) Non-REM sleep stage 2 – which is Categorization

3) Non-REM sleep stage 3– which is Distributed Processing

4) REM sleep – which is Acausal Story Creation & Processing

The reason for rapid eye moment in the REM stage is that eye movements add to realism when dreams are received by system 2, do not consume much energy and do not clash with other processes.

Sleep Cycles and their Purposes

In the sleep mode, stages of sleep cycle between non-REM sleep and REM sleep stages in an oscillatory manner multiple times. Their sequence is based on each stage gaining from the previous stages individually, collectively or cumulatively, in terms of effectively creating and processing the acausal story with the results of distributed processing and categorization stages. It also processes the same with unresolved thoughts and emotions, if any.

The same is simplified as follows:

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.

Besides gaining from previous stages, the other reason why sleep stages cycle is based on the fact that as all of them are equally important for the overall sleep processing, if for some reason the sleep period is curtailed, e.g., if a person aborts his sleep, each stage is curtailed proportionately.

Cycling of sleep stages is the core reason it does not make sense to study the topics of sleep and dreams individually.

Standby Mechanism

Once the brain enters sleep state, a standby mechanism is activated. In the standby mode, the non-conscious system 1 keeps a watch on sensory inputs based on a threshold. If any sensory input crosses such threshold, it alerts system 2, i.e., the self, which is in internal processing mode, i.e., in sleep mode, causing it to switch to general processing mode (i.e., causing it to wake up).

Although one can change such threshold to some degree using system 2, it is chiefly set by system 1 (often dynamically) and differs from person to person, which is the reason some people can be more easily awakened than others.

In Conclusion

  • As can be derived from the dream creation process, system 1 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, have no purpose or meaning other than acausal processing. The same is the reason why many of our dreams contain people and elements that are known to us, but are not intended to mean anything to us
  • Although some dreams are influenced by thoughts and emotions ingrained in the memory based on their strength and significance to the system 2, i.e., 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
  • As they are generated from random data, 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 the person has negative thoughts and emotions ingrained in his memory. The same goes for positive entities like objects of desire which are ingrained in the memory, for example, a girl of one’s dreams
  • Some dreaming also occurs in the 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). The same is also responsible for abrupt awakenings, nightmares, etc.
  • Repetitive usage of acausal thinking helps “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

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