Lizard Brain is the term used in popular psychology and personal development, referring to the older parts of the brain. In non-technical language, the lizard brain, supposed to be the very primitive part of the brain common between reptiles and mammals, is considered responsible for basic survival functions such as breathing and fight or flight response.
The lizard brain is commonly contrasted with the mouse and monkey brains. While the former represents the part of the human brain responsible for memory and emotion, the latter denotes the newer part of the brain, capable of complex cognitive functions and higher-order thinking.
The following diagram depicts this so-called triune model of the brain (+):
No matter how close to reality, this simplified divided model of the brain has been attractive for authors of management, psychology, and personal development books. For example, Seth Godin, the well-known business writer, has used the term extensively in his book Linchpin. Here are a few samples:
- Everyone has a little voice inside of their head that’s angry and afraid. The voice is the resistance, your lizard brain, and it wants you to be average (and safe).
- The lizard brain is hungry, scared, and horny.
- The lizard brain will fight (to the death) if it has to, but would rather run away.
- The lizard brain is not merely a concept. It’s real, and it’s living on the top of your spine, fighting for your survival.
John Medina, the author of the best-selling book Brain Rules, is also comfortable with using the term “lizard brain”:
Criticism of the model: lizard brain, mouse brain, and monkey brain
Lisa Feldman Barret, the well-known and respected neuroscientist, the author of various academic books, and chief editor of The Emotion Review journal, has criticised this model in simple words understandable for the non-technical audience.
In her book, Seven and a Half Lessons About the Brain, Barret describes the model as “one of the most successful and widespread errors in all of science.”
Look at the following passage from her book:
Barret tells the story behind this model and the way it got traction and survived till now. A physician named Paul MacLean has visually inspected the brains of lizards and mammals, including humans, and concluded that part of these brains is similar. He considered it as the old part, shaped in the early stages of evolution, and responsible for basic survival functions. In such a model, the human brain has extra parts sitting over this old brain, which evolved in later stages of evolution, responsible for complex cognitive functions.
But what’s the better description of the brain’s structure? Barret tells us that:
Why lizard’s brain is attractive to authors, coaches and mentors?
Most of the courses, classes and discussions about behavioral modification and emotion regulation revolve around a fundamental yet essential point: “You must monitor your first reactions and manage your impulses.” Or in other words: “Think twice before any judgment or doing anything.” This recommendation is crucial, and authors and coaches prefer to reinforce it with scientific evidence. Thus, instead of simply saying, “Beware of impulsive behavior,” they like to put it beside “scientific” pieces of evidence. Neuroscience is an attractive and persuasive term, and why not use these kinds of pseudo-neuroscientific descriptions as support for our recommendations?
Is it wrong to use this term? No. This simplified model can be helpful in teaching. The term lizard brain is much shorter and more understandable than “all fast emotional conservative automatic responses of the human brain.” But we have to remember and remind that we are not talking about the brain’s actual structure, and it’s just a metaphor.