MYTH BUSTERS: No, You Don’t Have a ‘Lizard Brain’
From: Science & Culture Today:
By Casey Luskin:
(339 WORDS) — How many of us sat through a college-level psychology or evolution course and heard the professor claim that we have a “lizard brain”? It’s just like ontogeny recapitulates phylogeny: an evolutionary model that many of us were taught in school, but it’s totally false.
According to the now-defunct hypothesis about ontogeny recapitulating phylogeny, evolution tacks new stages of development onto older ones to make new types of organisms. This view would therefore claim that your ancestors originally went through a “fish” stage of development, followed by a “reptile” stage, and then finally became a mammal, etc.
News from McGill University
Many evo-psych theorists would maintain that something similar happened with brain evolution — new neural components just got tacked onto old ones to create more complex brains with more and more advanced capabilities.
Photo by Егор Камелев on Unsplash
A new article from McGill University’s Office for Science and Society, “You Do Not Have a Lizard Brain,” explains the “lizard brain” theory — and why it is wrong:
We have all heard that we have a lizard brain. In fact, popular wandering hero Jack Reacher is said to have a highly reliable lizard brain, a sort of primitive instinct that alerts him to what is really going on.
On top of this ancestral brain, we are said to have evolved a second brain, full of emotions, shared with mammals like mice and horses. Lizards are detached, but mammals? We experience fear, anger, joy, defiance, and longing. And crowning this limbic system is what makes us uniquely human: a third brain capable of speech, of contemplation, and of complex thoughts.
Widely Believed, but False
Unlike ontogeny recapitulates phylogeny, the idea that we have a “lizard brain” is still widely believed. The McGill article cites a 2020 study, “Your Brain Is Not an Onion With a Tiny Reptile Inside,” which evaluated 20 introductory psychology textbooks and found among those that covered brain evolution “almost all … made the mistake of teaching students about the lizard brain.”