Brain Rule 2: The Brain Evolved...

For various reasons I find myself having to read through a book called Brain Rules.  The first two chapters are fascinating, although no doubt many will push back on its evolutionary approach.  The first chapter gives John Medina's first rule: Exercise!  Even a little exercise improves brain power.

He takes an evolutionary perspective.  Humans evolved to move.  That's how we survived as a species, he will say in the second chapter.  We moved 12 miles a day on average in the early days of our ancestors, he says.  It's stupid to cut recess out of public school education, he says.  It's like eating less in order to gain weight. I think this is the chapter where he says it cuts the risk of Alzheimers by something like 60%.

His second rule is that the brain evolved too.  It's a fascinating chapter.  "The brain appears to be designed to (1) solve problems (2) related to surviving (3) in an unstable outdoor environment, and (4) to do so in nearly constant motion" (31-32).  It did this so that we could survive long enough to have sex, have children, and live long enough to protect them to grow up to have more sex and children.  From a Christian perspective, I might add, it's not a particular grandiose view of humanity, but we are at least this much.  We may be more, but we are at least this much.

Later on in the chapter, he has a rather crass, even if possibly accurate sense of how the human womb evolved.  The key to the survival of our species, Medina claims, is not that we got stronger but that we got smarter (32, 37).  This meant that those with bigger brains--and thus bigger heads--survived more effectively than others.  This meant that women with larger wombs survived birth better--and that babies came out sooner.  Now parenting and childhood had to take place for years, unlike species where the offspring come out pretty much ready to go.

Medina has a fascinating version of human evolution.  We should keep in mind not only that his account may be debatable to some Christians but also among evolutionary experts themselves. Medina traces the key to our evolution to fundamental changes in the earth's weather (35).  It knocked our human ancestors out of the trees and onto flat ground that made offspring who stood upright and moved around a lot better suited to survive than those bent over.

Here is one of the take-aways from this chapter. We survived as a species, he says in so many words, because we became a species that improvises and adapts to new environments rather than staying in the same place.  We moved out all over the globe and adapted wherever we went.  His take-away for learning is something called Variability Selection Theory.  Learning is the interaction between two powerful features of the brain: "a database in which to store a fund of knowledge, and the ability to improvise off of that database.  One allows us to know when we've made mistakes.  The other allows us to learn from them" (37-38).

His conclusion is that "any learning environment that deals with only the database instincts or only the improvisatory instincts ignores one half of our ability."  Learning should not err on either extreme.  It should both provide content of knowledge and develop creative skills to be able to improvise and apply knowledge to new situations.

No matter how a person thinks the human brain developed, Medina's evolutionary model helps us picture what the three basic parts of the brain do.  First, we have a "lizard brain," basically our medula, our brain stem.  "The brain stem controls most of your body's housekeeping chores" (40), like breathing, heart rate, sleeping, and waking.

Then we have a second brain sitting on top of it, our mammalian or cat brain.  It is the seat of our emotions and animal functions like fighting, feeding, fleeing, and reproductive behavior.  The amygdala is responsible for emotions and emotional memory.  The hippocampus converts short term into long term memory.  The thalamus is the "control tower of the senses" (41).

But the human brain overshadowing these other parts is the cortex.  It is the part where our ability to fantasize comes from.  Humans can uniquely "attribute characteristics and meanings to things that don't actually possess them" (33).  Medina draws on "Dual Representation Theory" and actually starts off the chapter with the story of his son treating a stick as a sword (31).

This higher function of our brains allows us to "peer inside somebody's mental life and make predictions" (44).  It allows us to pool our strength together in order to survive.  That is the title of the chapter, Survival.  Rather than evolve stronger, Medina says, we decided to cooperate with each other and face that Wooley Mammoth together (43-44).

Accordingly, relationship is important to learning.  In his summary of the chapter, one of Medina's points is that "Symbolic reasoning... may have arisen from our need to understand one another's intentions and motivations, allowing us to coordinate within a group" (47).  And as a by-product, poor relationships between teacher and learner can often sabotage learning.