The Triune Brain
“The price we pay for the anticipation of our future is anxiety about it.”
The concept of the triune brain originated from the neuroscientist Paul D. MacLean around the 1960s as a way to explain the different stages through which the brain evolved. Starting from the reptilian brain, followed by the limbic system and the neocortex. We still have all of these structures in us and they affect much of our behavior. The triune brain model is a conceptual separation more than a physical one. We don’t really have three brains, these parts are interconnected and all active all the time. But it is a good way to conceptualize it in a simple way and starting to understand the way we operate (and it is a reminder of why you shouldn’t go shopping while you’re hungry!).
The Reptilian Brain: it is the first step in evolution. It was called the reptilian brain because of the belief that reptiles were mainly dominated by this structure. It activates the body and organizes its basic functions and needs like breathing or keeping the heart beating. This part of the brain really cares only about searching for food, safety, and sex. It reacts to dangers by physically mobilizing muscles, heart, sweat, fast breathing, etc… It is also the main center for our aggressive behavior, the defense of our territory, and ritual displays.
The Limbic System: (or paleomammalian brain): it is the center of our emotions, memory, motivation, and learning. It is the central processing of our feelings of fear, love, anger and all the emotions that are indispensable when we interact with others. They help us work within a group and makes us care for it, as well as it makes us care for, and love, our offsprings, family, and partners (caring for them is important if we want to keep them safe). It is also the root of our motivation to pursue a particular goal, and learning and adapt to a new environment. It helps us make decisions based on what FEELS right and also what feels good.
The Neocortex: it is the newest step in evolution and it is the predominant feature that differs humans from other animals. Our neocortex is the biggest in size and proportions compared to other animals (76% of our brain is neocortex).
The neocortex is the seat of our higher cognitive skills: perception, planning, abstract thinking, moral judgement, language, etc… It is the root of new inventions and basically every technology we are surrounded by. We owe our modern world to the neocortex. It gives us the free will to choose our path in any circumstance and the ability to plan out the steps necessary to achieve our goals.
These three systems don’t operate in isolation but are interconnected and they influence each other all the time! How we think affects how we feel, which then influences how we act. And it is not unidirectional from top to bottom. Each part can influence the other two; so that our thinking creates an emotion, but also our emotions influence our thinking, and our body then influences our feelings and our thinking. Our emotions can cloud our vision and our sense of perspective, making us feel that something can be the end of the world, and we then forget about it two days later. We might get angry, while actually, we are just hungry. We can get scared of events that might never happen, just because we saw them on TV. This is why you shouldn't go shopping while you’re hungry, or you should think twice before you send that angry email. Next time you feel the urge to do something take a moment to reflect, which part of the brain is actually influencing you?
If you would like to know more about how this system is connected to our feeling of stress, click here
Cheers
Bibliography and references
Sagan, Carl. The Dragons of Eden: Speculations on the Evolution of Human Intelligence. Published: 1977.
https://www.interaction-design.org/literature/article/our-three-brains-the-reptilian-brain
https://www.interaction-design.org/literature/article/our-three-brains-the-emotional-brain