Question: Have you heard that we have a reptilian, mammalian, and rational brain?
If you have, I’m not surprised! This is an extremely common belief in the yoga world. But it’s no longer considered accurate by modern neuroscientists. It’s an old myth we should let go of! 😱
The basic gist of this myth (called “the triune brain”) is that our brain evolved in three layers:
The oldest and deepest layer is the “reptilian brain” (also called the “lizard brain” or your “inner beast”). This layer is said to house our base instincts.
The middle layer of the brain is claimed to be our “emotional center” – a.k.a. the “limbic system”. (Our emotions are said to stem from our ancient mammal ancestors, so this layer of the brain is also called the “mammalian brain”.)
Finally, the outermost layer of the brain is said to be the newest layer. It’s called the neocortex and is allegedly the “rational center” of the brain.
Although this triune brain model tells a neat-and-tidy story that’s easily digestible, it’s an oversimplified model that’s been scientifically disproven. Evolution doesn’t actually work this way, and our brain certainly doesn’t function this way.
Rather than consisting of localized “centers” of psychological function (the emotion center, the rational center, the pain center, etc.), psychological functions actually take place on a whole brain level.
Our brain consists of a vast array of neural networks that span multiple brain regions to coordinate everything about the way we think, feel, perceive, and emote.
In other words, brain function is unimaginably more complex than the outdated triune brain model gives it credit for.
The Triune Brain Myth in Yoga
This scientifically disproven triune brain model unfortunately underlies many outdated approaches to psychology, and many of these ideas have made their way into the yoga world in the form of:
content in yoga teacher trainings
explanatory models in many somatics-based practices
approaches to psychology in numerous yoga therapy programs
If this is news to you, you are far from alone! In my experience, most people aren’t aware that the triune brain is a myth (and therefore practices and methods based on it should be questioned and critiqued). It’s a really tough myth to shake – probably because it resonates with ideas we really like to believe about human nature.
(BTW that tendency to believe ideas that resonate with what we already want to believe is called motivated reasoning, and it’s something we all do; in fact, our brains evolved to work this way!)
Anyway, there is SO much more to say about all of this. I’ve really only gotten started here in this blog post.
If you’d like to learn about TONS of essential insights about the brain and nervous system that are not commonly taught in the yoga world, take the brand new course that just launched on my website: Welcome to Your Brain: New Nervous System Essentials for Yogis!
I culled together incredible insights from a variety of disciplines to create this course content. The narrative I’ve put together in this presentation is one that I’ve never seen offered before in the yoga world. I have high hopes that you’ll learn a lot and will end up with a different (and more science-based) view of your body in the world.