I end each chapter a few more potential ways to apply the research in our daily lives. But these are not prescriptions. They are hypotheses. If you try them, you will be doing your own little research project to see whether they work for you.
Back to the jungle
What we know about the brain comes from biologists who study brain tissues, experimental psychologists who study behavior, cognitive neuroscientists who study how the first relates to the second, and evolutionary biologists. Though we know precious little about how the brain works, our evolutionary history tells us this: 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. I call this the brain’s performance envelope.
Each subject in this book—exercise, sleep, stress, wiring, attention, memory, sensory integration, vision, music, gender, and exploration—relates to this performance envelope. We were in motion, getting lots of exercise. Environmental instability led to the extremely flexible way our brains are wired, allowing us to solve problems through exploration. To survive in the great outdoors, we needed to learn from our mistakes. That meant paying attention to certain things at the expense of others, and it meant creating memories in a particular way. Though we have been stuffing them into classrooms and cubicles for decades, our brains actually were built to survive in jungles and grasslands. We have not outgrown this.
Because we don’t fully understand how our brains work, we do dumb things. We try to talk on our cell phones and drive at the same time, even though it is literally impossible for our brains to multitask when it comes to paying attention. We have created high-stress office environments, even though a stressed brain is significantly less productive than a non-stressed brain. Our schools are designed so that most real learning has to occur at home. Taken together, what do the studies in this book show? Mostly this: If you wanted to create an education environment that was directly opposed to what the brain was good at doing, you probably would design something like a classroom. If you wanted to create a business environment that was directly opposed to what the brain was good at doing, you probably would design something like a cubicle. And if you wanted to change things, you might have to tear down both and start over.
Blame it on the fact that brain scientists rarely have a conversation with teachers and business professionals, education majors and accountants, superintendents and CEOs. Unless you have the Journal of Neuroscience sitting on your coffee table, you’re out of the loop.
This book is meant to get you into the loop.
Survival: Why your brain is so amazing
Brain Rule #1: The human brain evolved, too
When he was 4, my son Noah picked up a stick in our backyard and showed it to me. “Nice stick you have there, young fellow,” I said. He replied earnestly, “That’s not a stick. That’s a sword! Stick ’em up!” I raised my hands to the air. We both laughed. As I went back into the house, I realized my son had just displayed virtually every unique thinking ability a human possesses—one that took several million years to manufacture. And he did so in less than two seconds. Heavy stuff for a 4-year-old. Other animals have powerful cognitive abilities, too, and yet there is something qualitatively different about the way humans think. How and why did our brains evolve this way?
A survival strategy
It all comes down to sex. Our bodies latched on to any genetic adaptation that helped us survive long enough to pass our genes on to the next generation. There’s no bigger rule in biology than evolution through natural selection, and the brain is a biological tissue. So it too follows the rule of natural selection.
There are two ways to beat the cruelty of a harsh environment: You can become stronger or you can become smarter. We did the latter. It seems most improbable that such a physically weak species could take over the planet not by adding muscles to our skeletons but by adding neurons to our brains. But we did, and scientists have expended a great deal of effort trying to figure out how. I want to explore four major concepts that not only set the stage for all of the Brain Rules, but also explain how we came to conquer the world.
We can make things up
One trait really does separate us from the gorillas: the ability to use symbolic reasoning. When we see a five-sided geometric shape, we’re not stuck perceiving it as a pentagon. We can just as easily perceive the US military headquarters. Or a Chrysler minivan. Our brains can behold a symbolic object as real by itself and yet, simultaneously, also representing something else. That’s what my son was doing when he brandished his stick sword. Researcher Judy DeLoache calls it Dual Representational Theory. Stated formally, it describes our ability to attribute characteristics and meanings to things that don’t actually possess them. Stated informally, we can make things up that aren’t there. We are human because we can fantasize.
We are so good at dual representation, we combine symbols to derive layers of meaning. It gives us the capacity for language, and for writing down that language. It gives us the capacity to reason mathematically. It gives us the capacity for art. Combinations of circles and squares become geometry and Cubist paintings. Combinations of dots and squiggles become music and poetry. There is an unbroken intellectual line between symbolic reasoning and the ability to create culture. And no other creature is capable of doing it.
The all-important human trait of symbolic reasoning helped our species not only survive but thrive. Our evolutionary ancestors didn’t have to keep falling into the same quicksand pit if they could tell others about it; even better if they learned to put up warning signs. With words, with language, we could extract a great deal of knowledge about our living situation without always having to experience its harsh lessons directly. It makes sense that once our species evolved to have symbolic reasoning, we kept it. So what was it about our environment that would give a survival advantage to those who could reason symbolically?
We adapted to variation itself
Most of what we know about the intellectual progress of our species is based on evidence of toolmaking. That’s not necessarily the most accurate indicator, but it’s the best we’ve got. For the first few million years, the record is not very impressive: We mostly just grabbed rocks and smashed them into things. Scientists, perhaps trying to salvage some of our dignity, called these stones “hand axes.” A million years later, we still grabbed “hand axes,” but we began to smash them into other rocks, making them more pointed. Now we had sharper rocks. It wasn’t much, but it was enough to begin untethering ourselves from a sole reliance on our East African womb, and indeed any other ecological niche. Then things started to get interesting. We created fire and started cooking our food. Eventually, we migrated out of Africa in successive waves, our direct Homo sapiens ancestors making the journey as little as 100,000 years ago. Then, 40,000 years ago, something almost unbelievable happened. Our ancestors suddenly took up painting and sculpture, creating fine art and jewelry. This change was both abrupt and profound. Thirty-seven thousand years later, we were making pyramids. Five thousand years after that, rocket fuel.
Many scientists think our growth spurt can be explained by the onset of dual-representation ability. And many think our dual-representation ability—along with physical changes that precipitated it—can be explained by a nasty change in the weather.
Most of human prehistory occurred in junglelike climates: steamy, humid, and in dire need of air-conditioning. This was comfortably predictable. Then the climate changed. Ice cores taken from Greenland show that the climate staggers from being unbearably hot to being sadistically cold. As little as 100,000 years ago, you could be born in a nearly arctic environment but then, mere decades later, be taking off your loincloth to catch the golden rays of the grassland sun. Such instability was bound to have a powerful effect on any creature
