without modern medical intervention. The solution? Give birth while the baby’s head is small enough to fit through the birth canal. The problem? You create childhood. Most mammals reach adulthood within months. Our long childhood gave the brain time to finish its developmental programs outside the womb. It also created a creature vulnerable to predators for years and not reproductively fit for more than a decade. That’s an eternity when you live in the great outdoors, as we did for eons.
But the trade-off was worth it. A child was fully capable of learning just about anything and, at least for the first few years, not good for doing much else. This created the concept not only of learner but, for adults, of teacher. Of course, it was no use having babies who took years to grow if the adults were eaten before they could finish their thoughtful parenting. We weaklings needed to out-compete the big boys on their home turf, leaving our new home safer for sex and babies. We decided on a strange strategy. We decided to try to get along with each other.
We cooperated: You scratch my back …
Trying to fight off a woolly mammoth? Alone, and the fight might look like Bambi vs. Godzilla. Two or three of you together—coordinating behavior and establishing the concept of “teamwork”—and you present a formidable challenge. You can figure out how to compel the mammoth to tumble over a cliff, for one. There is ample evidence that this is exactly what we did.
This changes the rules of the game. We learned to cooperate, which means creating a shared goal that takes into account our allies’ interests as well as our own. In order to understand our allies’ interests, we must be able to understand others’ motivations, including their reward and punishment systems. We need to know where their “itch” is. To do this, we constantly make predictions about other people’s mental states. Say we hear news about a couple: The husband died, and then the wife died. Our minds start working to infer the mental state of the wife: The husband died, and then the wife died of grief.
We create a view, however brief, into the psychological interior of the wife. We have an impression of her mental state, perhaps even knowledge about her relationship with her husband. These inferences are the signature characteristic of something called Theory of Mind. We activate it all the time. We try to see our entire world in terms of motivations, ascribing motivations to our pets and even to inanimate objects. The skill is useful for selecting a mate, for navigating the day-to-day issues surrounding living together, for parenting. Theory of Mind is something humans have like no other creature. It is as close to mind reading as we are likely to get.
This ability to peer inside somebody’s mental life and make predictions takes a tremendous amount of intelligence and, not surprisingly, brain activity. Knowing where to find fruit in the jungle is cognitive child’s play compared with predicting and manipulating other people within a group setting. Many researchers believe a direct line exists between the acquisition of this skill and our intellectual dominance of the planet.
When we try to predict another person’s mental state, we have physically very little to go on. Signs do not appear above a person’s head, flashing in bold letters his or her motivations. We are forced to detect something that is not physically obvious at all, such as fear, shame, greed, or loyalty. This talent is so automatic, we hardly know when we do it. We began doing it in every domain. Remember dual representation: the stick and the thing that the stick represents? Our intellectual prowess, from language to mathematics to art, may have come from the powerful need to predict our neighbor’s psychological interiors. As I said, your brain is amazing.
Why did I want to spend time walking you through the brain’s survival strategies? Because they aren’t just part of our species’ ancient history. They give us real insight into how humans acquire knowledge. We improvise off a database, thinking symbolically about our world. We are predisposed to social cooperation, which requires constantly reading other people. Along with the performance envelope, these concepts determine at the most fundamental level how our brains work.
Now that you’ve gotten the gist of things, let’s dive into the details.
Brain Rule #1
The human brain evolved, too.
• 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.
• We started with a “lizard brain” to keep us breathing, then added a brain like a cat’s, and then topped those with the thin layer known as the cortex—the third, and powerful, “human” brain.
• We adapted to change itself, after we were forced from the trees to the savannah when climate swings disrupted our food supply.
• Going from four legs to two to walk on the savannah freed up energy to develop a complex brain.
• Symbolic reasoning is a uniquely human talent. It may have arisen from our need to understand one another’s intentions and motivations. This allowed us to coordinate within a group, which is how we took over the Earth.
Brain Rule #2
Exercise boosts brain power.
IF THE CAMERAS WEREN’T rolling and the media abuzz with live reports, it is possible nobody would have believed the following story:
A man had been handcuffed, shackled, and thrown into California’s Long Beach Harbor, where he was quickly fastened to a floating cable. The cable had been attached at the other end to 70 boats, bobbing up and down in the harbor, each carrying a single person. Battling strong winds and currents, the man then swam, towing all 70 boats (and passengers) behind him, traveling 1½ miles from Queensway Bridge. The man, Jack LaLanne, was celebrating his birthday.
He had just turned 70 years old.
Jack LaLanne, born in 1914, has been called the godfather of the American fitness movement. He starred in one of the longest-running exercise programs produced for commercial television. A prolific inventor, LaLanne designed the first leg-extension machines, the first cable-fastened pulleys, and the first weight selectors, all now standard issue in the modern gym. He is credited with inventing an exercise that supposedly bears his name, the Jumping Jack. LaLanne lived to the age of 96. But even these feats are probably not the most interesting aspect of this famed bodybuilder’s story.
If you watch him during an interview late in his life, your biggest impression will be not the strength of his muscles but the strength of his mind. LaLanne is mentally alert. His sense of humor is both lightning fast and improvisatory. “I tell people I can’t afford to die. It will wreck my image!” he joked to Larry King. He once railed: “Do you know how many calories are in butter and cheese and ice cream? Would you get your dog up in the morning for a cup of coffee and a donut?” (He claims he hasn’t had dessert since 1929.) He has the energy of an athlete in his 20s, and he is possessed of an impressive intellectual vigor.
So it’s hard not to ask, “Is there a relationship between exercise and mental alertness?” The answer, it turns out, is yes.
Survival of the fittest
Though a great deal of our evolutionary
