In John Medina’s Brain Rules, rule #2 says, “The human brain evolved, too.” This chapter focuses on how our brains developed. One factor in that development was that our ancestors gave up on consistency. They didn’t have much choice; the changing environment slowly, steadily pushed them out of the trees and onto the grasslands.
Instead of learning how to survive in just one or two ecological niches we took on the entire globe. Those unable to rapidly solve new problems or learn from mistakes didn’t survive long enough to pass on their genes. The net effect of this evolution was that we didn’t become stronger; we became smarter. We learn to grow our fangs not in the mouth it in the head.
As Medina points out, learning to walk upright — something you can’t do in the trees — freed up our hands and was also energy-efficient, freeing energy to build and fuel our minds.
As we evolved, our brains became larger. The triune model sees three brains:
- The brain stem, or lizard brain, controlling basic functions like breathing, heart rate, sleeping.
- The mammalian brain, dealing with functions like “fighting, feeding, fueling, and… reproductive behavior.”
- The cerebral cortex or the human brain, managing most of what we think of as higher reasoning.
How did we manage this evolutionarily? We developed childhood.
Much of our brainpower develops after birth, which means our survival depends on adults who can protect children. we had to learn how to cooperate. We can form impressions about the internal states of other people, something known as the theory of mind.
Suppose you are not the biggest person on the block, but you have thousands of years to become one. What do you do? If you are an animal, the most straightforward approach is becoming physically bigger… but there is another way to double your biomass. It’s not by creating a body but by creating an ally. If you can establish cooperative agreements with some of your neighbors, you can double your power even if you do not personally told your strength.
Another major trait we developed is the ability to reason symbolically. Here, too, we need time. Under the age of three, children don’t reason symbolically very well. Past that age, they can grasp and wield powerful human tools like language; they can reason; and they can deliberately set out to learn.
Brain photo by jj_judes / Jude.