Your brain is not for thinking.
Why did human brains evolve? It’s common to assume that our brains evolve in some kind of upward progression – say from lower animals to higher animals, with the most sophisticated, thinking brain of all, the human brain, at the top. After all, thinking is the human superpower, right? Wrong.
The question is not answerable because there is no ‘why’. But we can presume what is your brain’s most important job. It’s not rationality. Not emotion. Not thinking. Not empathy.
Your brain’s most important job is to control your body – to manage resources – by predicting energy needs before they arise so you can efficiently make worthwhile movements and survive.
Of course, our brains do think and feel and imagine hundreds of experiences, such as letting you read this summary. But all of these mental capacities are consequences of a central mission to keep you alive and well by managing your body budget.
You have one brain, not three.
The ‘triune brain’ idea is one of the most successful and widespread errors in all of science. For example, when your taste buds are tempted by a slice of chocolate cake but you decline it because you just finished breakfast, it’s easy to believe that your impulsive limbic system pushed you in a cake-ward direction and your rational neocortex wrestled the pair into submission. But human brains don’t work that way.
Bad behavior doesn’t come from inner beasts and good behavior is not the result of rationality. Rationality and emotion are not at war… they don’t even live in the separate parts of the brain.
These ideas, if taken seriously, could shake the foundations of all sorts of sacred institutions in our society. In law, for example, attorneys plead their client’s emotions overwhelmed their reason in the heat of passion and therefore they aren’t fully to blame for their actions. But feeling distressed is not evidence of being irrational or that your so-called emotional brain has hijacked your supposed rational brain.
You have one brain, not three. To move past the three brain myth, we need to fundamentally rethink what it means to be rational, what it means to be responsible for our actions and perhaps what it means to be human.
Your brain is a network.
If you’ve heard that the left side of your brain is logical and the right side is creative, that’s just a metaphor that emerged from beliefs about the brain that are now outdated.
If real brains don’t work that way and the triune brain is a myth, then what kind of brain do we have? The answer begins with an important insight – your brain is a network, a collection of parts that are connected to functions as a single unit. The Internet Is a network of connected devices. Your social network is a collection of connected people. Your brain is a collection of a single, massive and flexible structure that consists of 128 billion neurons.
However, your brain is more than just neurons (it includes blood vessels, fluids and other kinds of cells that we don’t fully understand yet). Your brain network may even extend into your gut and intestines, where scientists have found microbes that communicate with your brain via neuro-transmitters.
As scientists learn more, we may discover better ways to describe its structure and function. Until then, understanding the brain as a complex network allows us to ponder how a human brain creates a human mind without any need for an allegedly rational and oversize neocortex.
Little Brains wire themselves to their world
To a remarkable extent, a baby’s genes are guided and regulated by the surrounding environment. The brain areas that are most centrally involved in vision, for example, develop normally after birth only if a baby’s retinas are regularly exposed to light. An infant’s brain also learns to locate sounds in the world based on the specific shape of the baby’s ear. Even stranger, a baby’s body requires some genes from the outside world that travel inside of bacteria and other critters and affect the brain in ways that scientists are only beginning to understand.
A baby’s wiring instructions come not only from the physical environment also from the social environment such as caregivers and parents. When you cradle a newborn girl in your arms, you present your face to her at just the right distance to teach her brain to process and recognize faces. When you expose her to boxes and buildings, you’re training her visual system to see edges and corners. Many other social things we do like cuddling and talking, sculpt her brain in necessary and irrevocable ways.
When it comes to the brain, nature versus nurture are alluring but not realistic. We have the kind of nature that requires nurture.
Our genes require a physical and social environment – a niche filled with other humans who shared our infant gazes, spoke to us with intent, set our sleep schedule and controlled our body temperature – all in order to produce a finished brain.
Your brain predicts (almost) everything you do.
When you were a child, your caregivers tended the environment that wired your brain. They created your niche. You didn’t get to choose the niche and you’re not responsible for your early wiring. If you grew up around certain types of people who wear the same type of clothing, agree on certain beliefs, practice the same religion or have a similar body shape or skin tones, these sorts of similarities tuned and pruned your brain to predict what people are like. Your developing brain was handed a trajectory.
Things are different after you grow up. You can hang out with all kinds of people. You can challenge the beliefs that you were swaddled in as a child. You can change your own niche. Your actions today become your brain’s predictions for tomorrow. Those predictions drive your future actions. You have some control to hone your predictions in new directions and you have some responsibility for the results.
Not everyone has broad choices about what they can hone, but everyone has some choice.
If you embrace this responsibility, think about the possibilities. What could be your life like? What type of person could you become?
Your brain secretly works with other brains.
Part of being a social species, as it turns out, is that we regulate one another’s body budgets – the ways in which our brains manage the bodily resources we use every day. Just like how caregivers help their babies’ brains to budget their resources, the mutual body budgeting and rewiring continue long after those little brains are grown. For your whole life, outside of your awareness, you make deposits of a sort into other people’s body budgets as well as withdrawals. Others do the same for you.
Some brains are more attentive to people around them, while others are less so. But everybody has somebody (even psychopaths are dependent on other people, just in an unfortunate way). Ultimately, your family, friends, neighbors and even strangers contribute to your brain’s structure and function and help your brain keep your body humming along.
This co-regulation has measurable effects. Changes in one person’s body often prompts changes in another, whether the two are romantically involved, just friends or strangers meeting for the first time. When you’re with someone you care about, your breathing synchronizes, as can the beating of your hearts. This sort of physical connection happens between infants and their caregivers, between therapists and their clients and among people taking a yoga class or singing in a choir together. One of us leads, the other follows, and sometimes we stitch. But if we don’t like each other, our brains are like dance partners who keep stepping on each other’s toes.
Brains make more than one kind of mind.
Your kind of mind is just one among many and you’re not stuck with the mind you have. You can modify your reminder. People do this all the time. College students use caffeine or amphetamines to create minds that can pull an all-nighter before an exam. Partygoers drink alcohol to create minds that are more relaxed and less inhibited in social situations. These chemical modifications last only for a short time. For long-lasting modifications, you can try new experiences or learn new things.
A particularly challenging way to modify your mind is by moving into another culture. If you’ve seen movies like Lost in Translation, you know how it goes. The characters are thrust into cultures so unfamiliar that they don’t know how to conduct themselves. Imagine landing in a culture where you don’t know even the most basic things like how to greet people or even stand to other people without being rude. Your mind must acclimate to this new culture. Scientists call this activity ‘acculturation’ and it’s like swimming in new ambiguous sense data and your brain needs to prune itself so it can efficiently guess what to do.
Acculturation is not always about crossing geographical boundaries. You can change cultures when you switch between work life and home life. When you change jobs. When you have to learn the different norms and jargon of the new industry. Military personnel, for example, have to acculturate at least twice – when they enter armed forces and when they return home from deployment.
Our brains can create reality.
A striking thing about social reality is we don’t often realize what we make it. The human brain mistakes social reality for physical reality. For example, humans vary tremendously like every animal species does. But unlike the rest, we organize this variation into little boxes with labels such as gender, race and nationality. We treat the labelled boxes as if they’re part of nature. The concept of ‘race’ often includes physical characteristics such as skin tone. But skin tone is on a continuum and boundaries between one set of shades and another maintained by people in a society.
We, as a culture, choose the features of discriminations and draw dividing lines that magnify the differences between the group we call ‘us’ and the group we call ‘them’.
The lines are not random but they aren’t stipulated by biology either. After the lines are drawn, people treat skin tone as a symbol for something else. That is social reality. Social reality is a superpower that emerges from an ensemble of human brains. It gives us the possibility to chart our own destiny and even influence the evolution of our species. We have more control over reality than we might think. We also have more responsibility for reality than we might realize.
Every type of social reality is a dividing line. Some help people, such as driving laws that prevent head-on collisions. Others hurt people such as slavery and social classes. People debate the morality of such dividing lines but each of us bears some responsibility every time we reinforce them. A superpower works best when you know you have it.