The 3 brains in your head


An organization of the brain

The Triune Brain is a theory from the 60s that tried to model the organization of the brain.

It is technically inaccurate as an explanation for brain activity as neuroscience understands it but it remains one of the very few good approximations of what is going on in our head.

It was nevertheless a major step from medieval thinking saying that Reason was in the head, Emotion in the heart and Instinct in the guts. It still feels that way, though.

Bill Williams, a psychology professor turned trader, came up with his own division of the Mind, Core-Right-Left, which sort of match the Reptilian-Limbic-Neocortex division of the Triune Brain and I combine them into Brain 1, 2 and 3 in this Blog. Please refer to The Divisions of the Mind Article for the various correspondences..

I may use the terms interchangeably in our articles when they apply best, so please refer to the article on the Division of the Mind and its charts when needed.

The Triune Brain division was based on anatomical observations of various animals.

  • Lizards and birds had only the Reptilian configuration
  • Early mammals had both Reptilian and Limbic system (also called Paleomammalian complex)
  • Higher mammals, including humans, had the Reptilian, Limbic and Neocortex (a.k.a. Neomammalian complex

This delimitation is not cast in stone, various species have a little bit of all in various proportions. Yet higher mammals have the biggest Neocortex.

In this Blog, I adapt the Triune Brain theory and divide the brain into Brain 1, Brain 2, and Brain 3.

How the brain was born

About 800 million years ago, living things grew in complexity and adopted a new structure to handle that new complexity. A digestive chamber fed muscles animated by nerve tissues which sent and processed signals. They were what we call animals.

That living structure continued to grow in complexity and what was nerve tissue started its own subdivision of labor, one part would carry information back and forth and another would process the said information. The brain was born.

That nerve blob evolved to higher complexity and is still in use today. It is in charge of all bodily functions and handles information at an incredible speed, about 3 million bits per second. It handles things like dosing insulin, regulating temperature, maintaining heartbeat. That is what I call Brain 1 or Core or also Reptilian Brain.

Brain 1

Survival implies improvement. Rare are the examples of species who could survive changing environments without adaption. Therefore, Brain 1 eventually had to grow beyond its functions.

Originally, Brain 1 would handle healing after harm is done. A later version (1.1?) came up with removing the body part from harm with what we call reflexes. The pain was the main information type.

Brain 2

Brain 2 came into existence by implementing a new approach, avoiding harm altogether as soon as it could be detected. That is what Fear does. As we all know, this device is also still fully active.

Other emotions were added to Brain 2 arsenal of information handling. It went up to actually being able to handle information from another brain, through facial recognition and body language. The fear felt by another fellow human can be perceived from a distance.

The speed and capacity of that brain set are unknown and deemed infinite. I call it Brain 2 or Limbic system or Right Brain.

Brain 3

Then came problem-solving. Nature found a way to avoid harm before harm even materialize.
That is what Brain 3 is doing.

Most authors agree on the Neocortex being the center of these functions. We also call it the Left Brain. One of the major drawbacks of this brain is its poor capacity at handling information, a mere 16 bits of information per second. This part of the Mind is regarded by many as the utmost achievement in the matter of higher evolution.

But Brain 3 is in fact only the most recent part of the brain and like any newly released products, it is full of imperfections.

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Brain 2 – Limbic – is creating our life

Let’s go back to what the Limbic system actually does. The concept of going away from harm using Fear as a trigger is introducing a new concept: Decision making. The Limbic system is the actual center of our Life and is of the utmost importance.

Limbic is the center of Emotions (Fear, Anger), Connection (Love/Body language/Facial Recognition) and Decision.

  • People with damage in the Limbic areas can be unable to make a decision, they keep pondering all the options using their Neocortex.
  • People whose ability to connect has been impaired or poorly developed can be pure logicians and can be classified somewhere in the Autistic spectrum.
  • People whose emotions are poorly synced can be either useless or dangerous. A Healthy balanced Limbic system is a requirement for a healthy mental life.

A poorly developed or under-performing Brain 3 – Neocortex only makes you an idiot but does not deprive you of a healthy happy life. A malfunctioning Brain 1 – Reptilian complex will no let you live long if at all.

The three brains are in constant communication

The three brains actually communicate with each other but the Limbic remains the Boss. It is fed information from the reptilians and the Neocortex, then reacts to the generated emotions and makes a decision.

The Neocortex is the only one we can act on voluntarily. It is the one we are conscious of.
We can only observe the other two, usually through dreaming, intuition or in a transient state (in the zone).

The Neocortex can have an influence on the other two but more so on the Limbic to which it is more closely linked. The Reptilian is also in conversation with the Limbic.

Brain 2 is often misled by Brain 3

The Neocortex (like the Reptilian) is consistently feeding information to the Limbic. But the Limbic/Reptilian relationship has been refined over millions of years whether the Limbic is still not filtering out properly what the Neocortex is providing.

  • Reptilian will provide real-life information, like pain, hunger, low sugar levels, high level of sexual hormones, etc.
  • The Neocortex will provide information about abstract danger like social embarrassment and also solutions to problems it churned about.
  • Only Neocortex can understand offensive language but passes the information as a threat the same way Reptilian will pass information about the sound of incoming danger.
  • The Limbic cannot distinguish between the signals from Reptilian or Neocortex. Thus things like Fear of Criticism are treated as urgent matters as the Fear of physical harm.

This is why being yelled at can put us in a state of fright, although there is no real physical danger.

The Neocortex is also the slowest of all three systems. Several million times slower than the others. It cannot handle all the information that is fed by the other two. So they pass it only a filtered version. – see the article, We are all blind.

So what we are conscious of is just a tiny fraction of what is going on.

None of these three brains is programmed to shut off. Limbic must stay alert and Reptilian would let you die if it took even a minute off. The Neocortex was not supposed to be off either but its poor capacity requires periods of suspension so some clean up can be done in its information files. This what we call sleep.

Your Brain and your life – Recap

  • What keeps us alive happens in the Reptilian system – Brain 1.
  • What makes us alive happens in the Limbic system – Brain 2.
  • What makes us conscious we are alive happens in the Neocortex Brain 3.