The Brain: The Story of You

by David Eagleman

Our overall brain activity is a mix of all these different frequencies, but depending on what we’re doing we’ll exhibit some more than others.

When we practice new skills, they become physically hardwired, sinking below the level of consciousness.

Practiced skills become written into the micro-structure of the brain.

A procedural memory is a long-term memory that represents how to do things automatically, like riding a bicycle or tying shoelaces. For Austin, cup stacking has become a procedural memory that is written into the microscopic hardware of his brain, making his actions both rapid and energy-efficient.

This ability to burn programs into the structure of the brain is one of its most powerful tricks.

Once etched into the circuitry of the brain these skills can be run without thinking – without conscious effort – and this frees up resources, allowing the conscious me to attend to, and absorb, other tasks.

During flow, the brain enters a state of hypofrontality, meaning that parts of the prefrontal cortex temporarily become less active. These are areas involved in abstract thinking, planning into the future, and concentrating on one’s sense of self.

The man who first began to illuminate the hidden depths of the unconscious was one of the most influential scientists of the twentieth century. Sigmund Freud entered medical school in Vienna in 1873, and specialized in neurology.

Freud’s insight was that much of their behavior was a product of unseen mental processes. This simple idea transformed psychiatry, ushering in a new way of understanding human drives and emotions.

Take an effect called “priming”, in which one thing influences the perception of something else.

Because the brain mechanisms for judging intrapersonal warmth overlap with the mechanisms for judging physical warmth, and so one influences the other.

In another study, it was shown that if you sit in a hard chair you’ll be a more hard-line negotiator in a business transaction; in a soft chair you’ll yield more.

Pasting a picture of a housefly in urinals at airports nudges men to aim better.

This view of governance is called soft paternalism, and Thaler and Sunstein believe that gently guiding the unconscious brain has a far more powerful influence on our decision making than outright enforcement ever can.

Consciousness gets involved when the unexpected happens, when we need to work out what to do next. Although the brain tries to tick along as long as possible on autopilot, it’s not always possible in a world that throws curveballs.

Although the CEO has access to very few details of the day-to-day running of the company, he or she always has the long-view of the company in mind.

This titanic complexity leaves us with just enough insight to understand a simple fact: our lives are steered by forces far beyond our capacity for awareness or control.

Listening to Jim’s neural activity – pop!pop!pop! – it’s impossible not to be awed. After all, this is what every decision in the history of our species sounded like. Every marriage proposal, every declaration of war, every leap of the imagination, every mission launched into the unknown, every act of kindness, every lie, every euphoric breakthrough, every decisive moment. It all happened right here, in the darkness of the skull, emerging from patterns of activity in networks of biological cells.

These neurons aren’t acting alone in their electioneering. At the same time, the competing possibility – lemon – is represented by its own neural party. Each coalition – mint and lemon – tries to gain the upper hand by intensifying its own activity and suppressing the other’s. They fight it out until one triumphs in the winner-take-all competition. The winning network defines what you do next.

Normally the two hemispheres are connected by a super-highway of nerves called the corpus callosum, and this allows the right and left halves to coordinate and work in concert.

But when the corpus callosum is severed, a remarkable and haunting clinical condition can emerge: alien hand syndrome.

The normal conflict running in the brain is revealed as the two hemispheres act independently of each other.

The trolley dilemma. When people are asked what they would do in this scenario, almost everyone pulls the lever. After all, it’s far better that only one person is killed rather than four, right?

The trolley dilemma, scenario 2. In this situation, almost no one is willing to push the man. Why not? When asked, they give answers like “that would be murder” and “that would just be wrong.”

To the brain, the first scenario is just a math problem. The dilemma activates regions involved in solving logical problems.

In the second scenario, you have to physically interact with the man and push him to his death. That recruits additional networks into the decision: brain regions involved in emotion.

Consider modern warfare, which has become more like pulling the lever than pushing the man off the tower. When a person hits the button to launch a long-range missile, it involves only the networks involved in solving logical problems.

Across the animal kingdom, every creature is wired to seek reward. What is a reward? At its essence, it’s something that will move the body closer to its ideal set points.

So when we’re faced with an array of possibilities, we integrate internal and external data to try to maximize reward, however it’s defined to us as individuals.

Using the Hollywood studios in our minds, we travel in time to our imagined futures to see how much value they’ll have. And that’s how I make my choices, comparing possible futures against one another.

Your valuation of everything around you is changeable, because quite often our predictions don’t match what actually happens. The key to effective learning lies in tracking this prediction error: the difference between the expected outcome of a choice and the outcome that actually occurred.

How does this work? There’s a tiny, ancient system in the brain whose mission is to keep updating your assessments of the world. This system is made of tiny groups of cells in your midbrain that speak in the language of a neurotransmitter called dopamine. When there’s a mismatch between your expectation and your reality, this midbrain dopamine system broadcasts a signal that re-evaluates the price point. This signal tells the rest of the system whether things turned out better than expected (an increased burst of dopamine) or worse (a decrease in dopamine). That prediction error signal allows the rest of the brain to adjust its expectations to try to be closer to reality next time. The dopamine acts as an error corrector: a chemical appraiser that always works to make your appraisals as updated as they can be. That way, you can prioritize your decisions based on your optimized guesses about the future.

Fundamentally, the brain is tuned to detect unexpected outcomes – and this sensitivity is at the heart of animals’ ability to adapt and learn. It’s no surprise, then, that the brain architecture involved in learning from experience is consistent across species, from honeybees to humans. This suggests that brains discovered the basic principles of learning from reward long ago.

But there’s a twist that often gets in the way of good decision making: options right in front of us tend to be valued higher than those we merely simulate.

Because the seduction of the immediate satisfaction pulls so strongly on our decision making, the housing bubble can be understood not simply as an economic phenomenon, but also as a neural one.

To the brain, the future can only ever be a pale shadow of the now. The power of now explains why people make decisions that feel good in the moment but have lousy consequences in the future: people who take a drink or a drug hit even though they know they shouldn’t; athletes who take anabolic steroids even though it may shave years off their lives; married partners who give in to an available affair.

Ulysses knew that his future self would be in no position to make good decisions. So the Ulysses of sound mind arranged things so that he couldn’t do the wrong thing. This sort of deal between your present and future self is known as a Ulysses contract.

Because self-control requires energy, which means we have less energy available for the next thing we need to do. And that’s why resisting temptation, making hard decisions, or taking initiative all seem to draw from the same well of energy. So willpower isn’t something that we just exercise – it’s something we deplete.

Consider the choice of monogamy – bonding and staying with a single partner. This would seem like a decision that involves your culture, values, and morals. All that is true, but there’s a deeper force acting on your decision making as well: your hormones. One in particular, called oxytocin, is a key ingredient in the magic of bonding.

After all, from an evolutionary perspective, we might expect that a male shouldn’t want monogamy if his biological mandate is to spread his genes as widely as possible. But for the survival of the children, having two parents around is better than one. This simple fact is so important that the brain possesses hidden ways to influence your decision making on this front.

They’re doing it because the drugs tap into fundamental reward circuitry in their brains. The drugs effectively tell the brain that this decision is better than all the other things it could be doing. Other brain networks may join the battle, representing all the reasons to resist the drug. But in an addict, the craving network wins.

We ask her to think about the cost crack cocaine has had to her – in terms of finances, in terms of relationships, in terms of employment. That activates a different set of brain areas, which we summarize as the suppression network.

Using fast computational techniques in the scanner, we can measure which network is winning: the short-term thinking of the craving network, or the long-term thinking of the impulse control or suppression network.

She may or may not be consciously aware of how she’s doing it, but by repeated practice she can strengthen the neural circuitry that allows her to suppress.

Equipped with an understanding of how human brains actually make decisions, we can develop new approaches beyond punishment.

An important technique is to train them to pause and consider the future outcome of any choice they might make – encouraging them to run simulations of what might happen – thereby strengthening neural connections that can override the immediate gratification of impulses.

Poor impulse control is a hallmark characteristic of the majority of criminals in the prison system.

Without the ability to weigh alternatives, we would be hostages to our most basic drives.

Although you have a single identity, you’re not of a single mind: instead, you are a collection of many competing drives. By understanding how choices battle it out in the brain, we can learn to make better decisions for ourselves, and for our society.

Heider and Simmel used this animation to demonstrate how readily we perceive social intention all around us.