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Do you know how alike you are with a Chimpanzee?

Almost 98.9%, genetically speaking. Not only that, you are genetically 94% similar to your pet and 90% with your cat.

You might be thinking ‘But I don’t behave like my pet or cat. No way

Then what separates us from pet, cat, or chimpanzees?

It’s our brain of course. The genes we have relevant to brain development is absent in other animals. We approximately have 3 million more neurons in our brain than that of chimpanzee’s. More neurons mean, more connections, more complexity, and more intelligence.

Do you know what’s in our head is the order of magnitude more complex than anything one sees in the entire universe. Although our brain is within us and we use in daily life but probably we still have no idea how this enigmatic brain works.

According to the physicist, Roger Penrose (University of Oxford)-

“If you look at the entire physical cosmos, our brains are a tiny, tiny part of it. But they’re the most perfectly organized part. Compared to the complexity of a brain, a galaxy is just an inert lump”

So let’s take a tour of our marvelous brain.

I am not going to discuss the anatomy of the human brain with you. That you must have read in your school and college. Just by a Google search, you can know everything about the anatomy of the human brain.

Instead, I am going to share an idea which fascinated me when I first got to know it.

Do you know you behave similarly as lizards or snakes behave?

There are a lot of similarities between you and your pet’s behavior.

How is that? And if so, then what makes us human?

In 1960’s neuroscientist Paul D. MacLean formulated a model of the human brain (The triune brain in evolution), describing the brain in terms of three distinct structures that emerged along an evolutionary path. That means his model describes how the human brain has developed over the years through evolution.

Dr. Paul D. MacLean inventor of Triune Brain Concept

According to his model, there are not only one brain but three independent brains exist in our head. Sounds strange! Try to remember the time when you wanted to do something but you knew you shouldn’t do that. from where these conflicting thoughts arise.

Also, you will feel hungry only when you will pay attention to it. As long as you are not thinking about food or hunger you are ok but the moment you pay attention, you will realize you are hungry. What’s happening! This is because of different parts of your brain.

According to MacLeon, these three brains are-

  1. The Reptilian Brain (R-Complex)
  2. The Limbic Brain (Paleomammalian Complex)
  3. The Neocortex (Neomammalian Complex)
The Human Brain

As suggesting the name, reptilian brain resembles main structures found in a reptile’s brain. Basal Ganglia part of the human brain represents the reptilian brain. The triune brain model suggests the basal ganglia was acquired first through evolution.

Basal Ganglia in Human Brain

This system of the brain is responsible for the most basic survival functions, such as heart rate, breathing, body temperature, and balance. This brain is mainly take care of our survival. When you try to hold your breath for a long time, as carbon dioxide builds up in your bloodstream, the reptilian brain is going to want to take over and make you breathe again. At extreme conditions, this part of brain makes your alert for danger.

Now think about reptiles like snakes, lizards. Their behavior is exactly the same as the functions of our reptilian brain. Survival is the main challenge for them. The reptilian brain is reliable but tends to be somewhat rigid and compulsive.

Limbic brain resembles little more complex animal kingdoms brain. This part of brain consist of various part of brain such as- amygdala, hippocampus, hypothalamus. This part is responsible for our abilities such as learning, memory, expressing emotions.

Limbic Brain in Humans

Limbic brain wrapped around the reptilian brain in a shell, or girdle. Now if you are curious to know the difference between reptilian and limbic brain then think about the difference between a snake and a cat. Unlike reptiles, mammals have some feelings and ability to learn. Training a mammal is much easier than a reptile. You got the difference.

Finally, the neocortex is our most newest brain. Remember I asked a question before ‘what makes us human’?

Well, this neocortex is the answer. In humans, this neocortex has grown immensely compared to any other animal and this makes us unique. Other primates like chimpanzee’s DNA differs from ours by only 1.6% as I said before, but a chimpanzee’s neocortex in the brain is not as developed as in humans.

What superpowers this part of the brain gives us?

All the higher-order conscious activities such as language, abstract thought, imagination, planning, and creativity to name a few are due to our neocortex.

Of special interest in this part is the prefrontal cortex, reside just behind our forehead. The prefrontal cortex may be slower in responding to incoming information than the limbic system but is much more sophisticated in its processing. Such “slow” thinking is the hallmark of our human intelligence. Complex and new thinking on technical, emotional, social, and logical planes take place here. This is where ideas grow. In short, your neocortex makes you more of a human.

Prefrontal cortex in neocortex

So what’s the conclusion?

MacLean’s model claims that activity in the three brain regions (reptilian brain, limbic system, and neocortex) is largely distinct when we are engaged in each of the mental activities outlined above.

For example, when we are in danger and must respond quickly, as an act of self-preservation, the reptilian structure is aroused, preparing us for action by initiating the release of chemicals throughout the body. When we are watching a shocking news story or receive an upsetting message, the limbic system is stimulated and, again, chemicals are released, which create our experience of emotions. Finally, when we are making decisions, solving problems or reasoning, the neocortex is engaged, without the involvement of the other brain structures.

But modern brain images have revealed that distinct parts of the human brain are not independently active during any emotional or rational experience, Various parts of the brain are simultaneously active in those time.

Nonetheless, MacLean’s model is an oversimplified concept and it is not entirely true. However, it’s neither entirely wrong also. Undoubtedly triune brain concept provides us a useful way to asses the relationship between the structure and functions of the human brain. It helps us to understand the analogy between the human brain and other creature’s brain on the planet earth.

You know what fascinates most about this triune model of the brain, it’s the fact which often people used to say to other human beings ‘become a more human’.

I used to think how anyone can become ‘a more human’. A human is a human, what is more and less about that. But after knowing about triune brain concept I think it’s not a wrong statement.

See, if your reptilian brain is more active, you will be more aggressive, anxious and scared and less aware, creative or inventive. In such cases, your behavior is more like a reptile (lizard/snake) than like a human. Every time you get angry or too much aggressive your neocortex becomes less active, in other words, you become a reptile from a human.

You know what’s the good news, our neocortex is not rigid but of plastic nature which means we can develop our neocortex at any time of your life to become more of a human. You just need to use your neocortex more often in daily life.

Be creative whenever possible, practice to keep your mind calm, reflect more often, learn new things like a new language or instrument or any skill you like. All of these will utilize and develop your neocortex and will make you a better human.

The human life is a gift to you, don’t waste it by becoming a reptile or animal.

Have a humanly week. Until next time -Joy


  2. The Concept of the “Triune Brain”
  3. 3 Brains in One
  4. The Triune Brain

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