“As a neuroscientist, I see scientific myths about the brain repeated regularly in the media and corners of academic research,” [says psychologist Lisa Feldman Barrett in her book Seven and a Half Lessons About the Brain.]
The myth she targets in a recent article at Nautilus is the “triune brain,” the idea that our brain developed and continues to function in three successive layers.
But is there really a lizard brain that predates the early and late mammal brain? Not that Lisa Feldman Barrett can tell, because “ Most neurons have multiple jobs, not a single psychological purpose,” as opposed to being puzzle pieces that only fit in one place.
“This compelling tale of brain evolution arose in the mid 20th century, when the most powerful tool for inspecting brains was an ordinary microscope. Modern research in molecular genetics, however, has revealed that the triune brain idea is a myth. Brains don’t evolve in layers, and all mammal brains (and most likely, all vertebrate brains as well) are built from a single manufacturing plan using the same kinds of neurons.
Nevertheless, the triune brain idea has tremendous staying power because it provides an appealing explanation of human nature. If bad behavior stems from our inner beasts, then we’re less responsible for some of our actions.”