In this post, we’ll unpack all you need to know about the Triune Brain, defining exactly what it is, the different parts and their unique characteristics and more.
What Is The Triune Brain?
The Triune Brain is a simplified model of brain development based on an evolutionary view that divides the human brain into a hierarchy of three distinct layers and describes how they each interact.
The 3 Layers Of The Triune Brain
There are 3 layers to the Triune Brain: the reptilian brain, mammalian brain and human brain. All three layers work symbiotically but with different purposes.
Reptilian Brain
The reptilian brain is located within the hindbrain. It is thus the biological part of the brain which evolved around 500 million years ago. It is associated with the warrior archetype which seeks freedom. Its purpose is survival and therefore it wants to avoid pain by looking for safety and attending to risks. It is associated with the hormone acetylcholine.
Mammalian Brain
The mammalian brain is located within the midbrain. It is thus the social part of the brain which evolved around 250 million years ago. It is associated with the lover archetype which seeks love. Its purpose is feeling and therefore it wants to gain pleasure by looking for rewards and attending to opportunities. It is associated with the hormone dopamine.
Human Brain
The reptilian brain is located within the brain stem. It is thus the intellectual part of the brain which evolved around 2.5 million years ago. It is associated with the magician archetype which seeks truth. Its purpose is thinking and therefore it wants to find connection by looking for bonding and attending to relationships. It is associated with the hormone oxytocin.
Triune Brain Table Summary
Below is a table summarising the three layers of the Triune Brain and also their characteristics.
| Reptilian Brain | Mammalian Brain | Human Brain | |
|---|---|---|---|
| Region | Brain Stem | Limbic System | Neocortex |
| Age | 500 Million | 250 Million | 2.5 Million |
| Archetype | Warrior | Lover | Magician |
| Purpose | Surviving | Feeling | Thinking |
| Wants To | Avoid Pain | Gain Pleasure | Find Connection |
| Looks For | Safety | Rewards | Bonding |
| Attends To | Risks | Opportunities | Relationships |
| Neurotransmitters | Acetylcholine | Dopamine | Oxytocin |
Summary (TL;DR)
The Triune Brain is a hierarchical model of the human brain that represents the gradual acquisition of the brain structures throughout evolution. It consists of three distinct layers; the reptilian brain, the mammalian brain and finally the human brain.
By knowing how each region is responsible for specific mental activities, we can therefore gain a clearer understanding of the natural and instinctual human needs and behaviour.
