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Mind Wide Open: Your Brain and the Neuroscience of Everyday Lifeby Steven Johnson
PREFACE Kafka's Room
How pathetically scanty my self-knowledge is compared with, say, my knowledge of my room....There is no such thing as observation of the inner world, as there is of the outer world.
The idea for this book began with a nervous joke — a handful of nervous jokes, to be precise. A few years ago, thanks to a lucky convergence of events and a long-standing curiosity, I found myself in the office of a biofeedback practitioner, lying on a couch with sensors attached to my palms, fingertips, and forehead. As we talked, the two of us stared into a computer monitor, where a series of numbers flashed on the screen like some kind of low-budget version of the CNBC ticker tape. The numbers documented precisely how much I was sweating and updated several times a second. I've never taken a lie detector test, but something about having a stranger ask me questions while keeping a close eye on my sweat glands put me on edge. And so I started making jokes.
Getting a little tense was partly the point of the exercise. The machine I was attached to was tracking changes in my adrenaline levels, the "fight-or-flight" hormone secreted by the adrenal glands in situations that require a sudden surge of energy. Increased adrenaline can be detected through a number of means: because the hormone diverts blood from the extremes of the body to the core, drops in temperature at the extremities often suggest a release of adrenaline (hence the sensors on my fingertips). Sweating is also a telltale sign of heightened adrenaline levels. Because damp skin conducts electricity more effectively than dry skin, the electrodes on my palms could track how much I was sweating by monitoring changes in conductivity over time.
Biofeedback systems are designed to give you a new kind of control over your body and mind by making physiological changes visible in a new way. After a few sessions, biofeedback users learn to "drive" their adrenaline levels up or down almost as though they were deciding to lift a finger or bend a knee. The brain, of course, is constantly adjusting adrenaline levels anyway — it's just that you're not usually aware of the process other than as a background sense of increased energy or calm.
For the first five minutes of the session, my adrenaline levels remained at the midpoint of the scrolling chart, bouncing around ever so slightly, but with no real pronounced variation. And then something in the situation — I can't remember now what it was — caused me to make an offhand joke. We both chuckled at my remark and then noticed that a huge spike had appeared on the monitor. Making the joke had triggered a surge of adrenaline in me. Or was it the reverse? Perhaps the rise in adrenaline was me mentally revving the engines before launching my joke into the environment. Whatever the causal chain, my joke-telling and my adrenaline levels were locked in some kind of chemical embrace.
The extent of that link became clear at the end of our session, when the therapist handed me a printout of my adrenaline levels plotted over our thirty-minute encounter. It was, simply put, a timeline of my attempts at humor: a flat line interrupted by five or six dramatic spikes. I looked at that paper and thought: I've caught a glimpse of me here, viewed from an angle that I've never experienced before. I'd known for many years that I had a tendency to crack jokes compulsively in certain social situations, particularly in situations where the formality of the setting made humor a riskier bet. But I'd never thought about those jokes as triggering a chemical reaction in my own head. Suddenly, they seemed less like casual attempts at humor and more like a drug addict's hungering for a new fix.
I knew those adrenaline surges were just the tip of the iceberg. The creation and appreciation of humor is a remarkably complex neurological event, involving many parts of the brain and a host of chemical messengers. Doctors at the University of California Medical School, for example, recently located a small region near the front of the left brain that appears to trigger the feeling of mirth; while treating a sixteen-year-old epileptic patient, they applied a tiny jolt of electric current to the area, which caused the patient to find humor in whatever she happened to be looking at. This wasn't merely a physical reflex of laughter: things genuinely seemed funny to her when the region was stimulated. ("You guys are just so funny — standing around," she told her startled doctors.) Laughter itself involves a complex array of muscle actions, and there is increasing evidence that it triggers the release of small amounts of endorphins, the brain's natural painkillers. (The next time you visit a comedy club, think "opium den.") But making jokes in conversation also requires a subtle sense of one's audience, a feel for their sense of humor and state of mind. Such outer-directed imagination is itself governed by another part of the brain, a part believed to be damaged in autistics and that accounts for their strained social interactions.
This is what came to my mind as I thought about my nervous jokes on the biofeedback practitioner's couch: that with each of those jokes somewhere in my head there was an elaborate electrochemical ballet unfolding, one that had been evolving since my first smile, or before. And now I had glimpsed a subsection of that inner performance as it happened. I found myself wondering how many of these little chemical subroutines are running in my brain on any given day? At any given moment? And what would it tell me about myself if I could see them, the way I could see those adrenaline spikes on the printout?
And so biofeedback started me on my quest. I set out to track down as many charts, real-time displays, and 3-D models of my mental life as I could find. I talked to some of the world's leading neuroscientists, asking them the question I'd been asking myself: "How had understanding the brain changed the way they thought about themselves?" I also found technology startups and armchair enthusiasts who had embraced brain science as a tool for self-exploration. It was a propitious time to make this journey. Over the past three decades, science has given us extraordinary glimpses of the brain's inner geography, illuminating the amazing extent to which different tasks activate clearly defined regions: recognizing the face of a loved one, or planning a grocery list, or stringing together a sentence. Thus far, these new scientific tools have been employed mostly to observe people who have suffered neurological damage and to assess the mental maps shared by all human brains. But brains are like fingerprints — each of us possesses a unique neurological topography. We now have the technology in place to picture that inner landscape, in itself as it really is. These are tools, in other words, for exploring our individual minds, with all their quirkiness and inimitability. These are tools for capturing who we are, on the level of synapses and neurotransmitters and brain waves. Every human brain is capable of generating different patterns of electrical and chemical activity. The promise of these new tools involves being able to figure out what your pattern looks like. And then figuring out what that pattern tells you about yourself.
It's likely that you've thought about the patterns of your own brain's wiring before. The general movement of popular psychology over the past century has been one from deeply figurative descriptions of mental traits toward greater physiological specificity: the movement, in a sense, from Oedipus to the neuron. Adrenaline itself has entered our everyday lexicon, as has the notion of our body administering quick chemical fixes purely for pleasure: we do things, we say, for the adrenaline rush, or the endorphin high. Radio ads now tout various wonder drugs' ability to alter our neurotransmitter profiles as though they were selling dandruff shampoo. If you've read Listening to Prozac, you've probably met a person who seemed depressed and thought: hmm, very low serotonin. But such responses are just hunches about our inner physiological states, and crude ones at that. There are dozens of so-called information molecules in your body — neurotransmitters, hormones, peptides — each playing a key role in your shifting emotional response to external events, triggering everything from the nurturing instinct in mothers to the agitated surge of a panic attack. Could tools that measure the minute-by-minute levels of those substances in your body and brain teach you something about your own emotional toolbox? Could they help you make sense of your dreams, or your phobias? We've learned to track our mood changes with a statistician's exactitude, to explore our childhood memories, to keep our minds alert with exercise. But your moods and memories and perceptions are themselves derived from electrochemical activity in your brain. What could you learn about yourself if you could catch a glimpse of that activity directly? If you could see what your brain looked like when it was remembering a long-forgotten childhood experience, or listening to a favorite song, or conceiving a good idea?
Brain-imaging tools are miracles of modern science, but they are not the only channels to your mind's inner life. Simply possessing a more informed understanding of your brain's internal architecture can change the way you think about yourself. Part of such a process involves separating out mental routines that you typically experience in unison. If you know nothing about what's actually happening in your head, the neurological activity you experience is invisible: it's just you being yourself. But the more you learn about the brain's architecture, the more you recognize that what happens in your head is more like an orchestra than a soloist, with dozens of players contributing to the overall mix. You can hear the symphony as a unified wash of sound, but you can also distinguish the trombones from the timpani, the violins from the cellos. To come to a comparable understanding of your own head, you don't need a million-dollar imaging machine. You just need to learn something about the brain's components and their typical patterns of activation. Sometimes those components come in the form of specialized brain regions; sometimes they come in the form of chemicals, like serotonin. Invariably, a certain mood that strikes you will contain a mix of both, the result of both neurochemical release and predictable activity in specific regions of your brain.
As you learn to detect these brain components, you start to recognize how much multitasking is really going on in your own head. You realize that the emotion you feel isn't simply a reaction to the world at that moment, but rather something closer to a drug, with a strange life of its own. There's what we used to call a "rational" you and an "emotional" you, and the two aren't always in sync. Brain science has now given us more accurate descriptions of these two sides of a personality, mapped onto specific regions of the brain. Instead of "rational" and "emotional," today we have the "neocortical" you and the "limbic" you.
Consider this situation, which you've probably encountered many times before. You're in a perfectly good mood, having a conversation with a friend or colleague. You're not particularly aware of your emotional state, but it's purring along behind the scenes, making your dialogue free and unencumbered. And then your friend makes a passing reference to something unsettling, maybe a little stressful. Not earth-shattering, not immediately life-jeopardizing, but stressful nonetheless. Maybe he's alluded to some upcoming corporate retreat you haven't been invited to, or a tax deadline you'd forgotten about. Whatever it is, the news triggers a falling sensation in your body; you feel deflated and on edge.
And then your friend says something that surprises or distracts you, and the depressing news flies out of your working memory, replaced by some other thought. At this moment, something uncanny happens in your head, not unlike the feeling of déjà vu. You feel the stress in your body and your head, but you can't remember what triggered it in the first place. The feeling has been separated from the thought. Or put another way, you've lost the thought, but the feeling keeps on churning. Normally in this type of a situation you end up rewinding the tape of the conversation in your head — What were we just talking about? — and you locate the original item after a few seconds, at which point your mental state seems to snap back into place, just like the feeling of déjà vu lifting and linear time reinstating itself. You're still stressed, but at least you know the reason why.
Discontinuities occur like this because your conscious, second-by-second processing of a verbal conversation happens in one part of your brain, while your emotional evaluations happen somewhere else. Most of your immediate focus on generating and comprehending spoken words takes place, broadly speaking, in the prefrontal lobes of the neocortex, the most evolutionarily modern part of the brain. (Two small regions are particularly crucial: Broca's and Wernicke's areas, the former largely focused on creating speech, the latter on processing incoming words.) But the emotions largely issue forth from areas located below the cortex, the region often called the "limbic system," while some of their bodily effects are triggered one layer below the limbic system, in the brain stem that lies at the top of your spinal column. The activity in the prefrontal lobes consists mostly of the flash of neurons talking to each other in a very small region of your head, while the limbic system starts a cascade of events that lead to the release of chemicals that travel throughout the body, including one called "cortisol" that is responsible for much of the physical damage caused by long-term stress.
So when you hear that stress-inducing sentence, two reactions go off in your head: your language centers and working memory decode the meaning and put it front and center in your consciousness; and a subcortical system triggers the stress response, releasing cortisol and other chemicals throughout your brain and body. The two systems operate at fundamentally different speeds, the prefrontal activity unfolding on the level of microseconds and the stress system on the level of seconds or even minutes. That's why the two can get out of sync with one another. You think of something stressful and just as quickly forget about it. The prefrontal lobes can move that fast. But your emotional systems lag behind — there's still cortisol floating in your bloodstream thirty seconds after the news vanishes from your working memory. And so the feeling stays alive in you.
The question is: for that moment of disconnect, what exactly is in charge here? Your frontal lobes or your limbic system? And which one should you trust?
Brain science books sometimes suffer from a recurrent problem, one with no small measure of irony. The subject matter of a book about the human brain is, by definition, as close to home as you get. (These books are being read by human brains, after all.) But the deeper you delve into the details of brain anatomy, the higher the ratio of Latinate to English words becomes, and before long the lay reader is struggling to keep track of names like the "cingulate cortex" and the "nucleus accumbens." Some books try to scale this learning curve by starting off with a crash course in neuroanatomy. My approach is different: we'll start instead with a brain in action — feeling fear, laughing at a joke, coming up with a good idea — and tease out the underlying mechanisms as we go.
I've also tried to limit the terminology needed to read this book: a half dozen chemicals, a half dozen brain regions, and a rudimentary understanding of the way neurons communicate. It is one of my fundamental assumptions that you can get something useful out of neuroscience with this level of mastery. (For the aficionados and the extracurious, I've included more detailed explanations in the endnotes.) The brain contains multitudes, as Whitman said in another context, but you don't need to memorize them all to be a better user of your brain. If you know the landmarks, you can get your bearings. And when you're navigating a space as complicated as your own brain, getting your bearings can make all the difference.
If you've read a little about the brain over the past decade, you've no doubt encountered two topics that have dominated the public discussion of brain science. The first has to do with explaining consciousness, what the neuroscientist Antonio Damasio calls "the feeling of what happens." The second has to do with the field of evolutionary psychology, which argues that our brains contain a kind of mental toolbox selected over millions of years of evolution to help our ancestors survive and reproduce in challenging environments. Consciousness and evolution are each fascinating avenues for exploration, but this book will try to sidestep both, in slightly different ways.
Let's start with consciousness. Imagine you're seeing the face of a loved one after a long time apart, and feeling the pleasurable emotions triggered by that sight. We know a great deal about the path of incoming visual stimuli, shuttling information about the light bouncing off the contours of the face from your optic nerve to the sensory cortex. We know that this information resonates with memory storage systems controlled by the hippocampus, helping you remember details about your loved one. We also know quite a bit about the chemicals released in your brain that conjure up the feeling of emotional warmth. Thanks both to modern imaging technologies and studies of patients with localized brain damage, we can describe with truly remarkable precision the neurological ballet performed in your head when you gaze at the face of a child or spouse. But our scientific vision grows foggier when we try to explain how those patterns of neurochemical activity somehow create your first-person experience of that gaze: the "faceness" of your loved one's face, the "emotionness" of the emotional feeling. Consciousness theorists call these properties "qualia": the brain's representation of both the external world and the body's internal state — the taste of red wine, the look of light shimmering on water, the feeling of sudden fear hijacking your body.
It seems preposterous at first, but there is a real question as to why we need qualia at all. We could theoretically have evolved brains capable of the entire range of human mental responses — processing internal and external stimuli, evaluating situations as either emotionally positive or negative, executing long-term plans — without actually feeling any of these processes. We'd be like robots or zombies, indistinguishable from normal humans from the outside but empty on the inside. So the question becomes: how did this strange property of mind come about? The brain is ultimately just a big lump of atoms strung together in a particular configuration, no different in this sense from a teakettle or a crown of broccoli. Presumably the teakettle and the broccoli aren't conscious of themselves or their environment, so why should we be?
To simplify almost to the point of parody, there are four competing answers to that question on today's consciousness stage. The first is that the broccoli and the teakettle are conscious in some unimaginably different way from how we are. In other words, qualia is a property of matter itself, and the human brain is simply the most advanced qualia recording apparatus yet evolved. The second answer is that something unique exists in the configuration of cells that makes consciousness happen in brains and not in broccoli, though the nature of that something is a matter of great debate. The third answer implicates a mystery substance not yet understood by science — quantum behavior, perhaps, or some kind of spiritual life force — that turns a bunch of interconnected cells into a feeling brain. The fourth is the trick answer, proposing that one of the properties of consciousness is that it can't explain itself, and so we'll never get to the bottom of qualia no matter how scientifically and technologically adept we become.
These are all mesmerizing possibilities, even if they do tend to induce a kind of existential vertigo (or make you a little squeamish the next time you drop a piece of broccoli into a pot of boiling water). I wouldn't be at all surprised if one of the many theories of consciousness proposed in the past decade turns out to be largely correct. But science is very far from a consensus on this question right now, and I suspect it will remain in that state for the foreseeable future.
And so in this book, I've made it a matter of policy to avoid the question of consciousness as often as possible. Running away from the problem of qualia turns out to be a relatively healthy strategy, because there's a huge number of interesting and productive things that you can say about the brain without tackling the question of why consciousness feels the way it does. Think about my biofeedback session and my joke-telling adrenaline fix. Getting even that brief glimpse of my brain's chemical feedback system taught me something new about my personality and my conversational habits, and sharpened my awareness of the way making jokes changed my internal mood. (And explained why I sometimes had a tendency to make jokes inappropriately.) But despite these insights, I have no idea whatsoever why an adrenaline rush feels the way it does. I can describe its edgy uplift, compare it to the effects of exogenous drugs like caffeine, predict the ways it will change my subsequent behavior. But I can't tell you where the qualia of adrenaline comes from. It would be nice to know, of course, but fortunately it's not the only kind of knowledge that neuroscience can impart to us.
Then there's the evolutionary psychology debate, which runs parallel to — and is often indistinguishable from — the question of nature and nurture. Are our mental faculties simply the product of evolved genes, or are they shaped by the circumstances of our upbringing? Unlike the mysteries of consciousness, this question has a clear, and I believe convincing, answer: they're both. We are a mix of nature and nurture through and through, and it's precisely the interplay between evolved tools and cultural experience that creates the richness of the human condition.
In this book, I discuss some of the properties of the brain in terms of evolution, because a Darwinian perspective can sometimes illuminate features that might otherwise be shrouded in darkness, or help us understand drives and habits of mind that are unduly powerful or hard to shake. In chapter four, for instance, we'll look more closely at the brain science of laughter, and part of that analysis will touch on why laughter evolved in the first place, which in turn helps us understand something new about when and why we laugh in everyday life. (It has much less to do with humor than you might think.)
So evolutionary explanations will not be entirely absent from the chapters ahead, but neither will they be front and center. You can be agnostic about — or downright hostile toward — the premise of the evolved brain and still gain something from modern brain science, because on a basic level, the languages of nature and nurture are written in the same ink. My brain, for instance, may be releasing adrenaline with each successful punch line because millions of years of evolution endowed me with DNA that wired it that way. Or it may be that some unique set of circumstances from my childhood influenced that circuit in my brain. Most likely, of course, it's a bit of both: adrenaline release during laughter may be a common human trait, just a little exaggerated in my case. But whatever the original cause, the wiring is there in my head, releasing its adrenaline like some kind of neurochemical Old Faithful. It's fascinating to speculate whether a specific trait came from your ancestors or your fifth-grade teacher, but you don't need to have a convincing answer to learn about the inner life of your brain.
When public conversation turns to the way our biology shapes our behavior, we often encounter a quick denunciation of the entire premise: someone will claim that talking about minds in biological or Darwinian terms is "biological determinism," a highbrow, sanitized version of the old horrors of racism, eugenics, and social Darwinism. For the most part, these fears are unfounded. Evolutionary psychology addresses the shared characteristics of the human species, what unites us all irrespective of race or culture — exactly the opposite of what a race-based inquiry into our biological roots would attempt to discover.
Of course, the one place in which the evolutionary psychologists have in fact emphasized differences over commonalities is the fraught world of the sexes. Because so much of natural selection is predicated on reproductive success or failure, and because men and women have such different biological stakes in the act of reproduction, and because the sexual divide has been evolving for hundreds of millions of years, and not hundreds of thousands — it is inevitable that natural selection would craft slightly different toolboxes for each sex. Viewed with modern imaging technologies, men's and women's brains are nearly as distinct from each other as their bodies are. They have reliably different amounts of neurons and gray matter; some areas linked with sexuality and aggression are larger in men than in women; the left and right hemispheres are more tightly integrated in women than in men. And of course, those brains — and the bodies they are attached to — are partially shaped by two totally different kinds of hormones, the androgens and estrogens, which play a key role both in development and adult life experiences. Men and women are most certainly not from Mars and Venus, but it is entirely fair to say that they are on different drugs. A world in which the sexes were mentally indistinguishable might be a less conflict-ridden world, though also a little duller. But the truth is it is not the world we inhabit. Writing a book about brain science without describing some of these differences would be an exercise in bad faith, emphasizing politics over science in a way that does injustice to both.
In the past few decades, a certain type of science story has become commonplace in the media. You've probably encountered dozens of renditions of it: scientists announce that they have uncovered the roots of a particular human psychological attribute. The two standard variations of this story are the brain scanning version and the evolutionary psychology version. In the former, scientists pick some trait or behavior — a craving for sugar, say — and use a brain-imaging device to scan someone while they're experiencing that craving. The part of the brain that lights up during the scan — the dorsal striatum, in this case — is identified as the "craving center" of the brain, and before long a press release is being drafted.
The evolutionary psychology version of the same story follows a different path. Instead of locating neurological roots, the scientists discover historical roots: the evolutionary history of why one trait came to be selected. This is a more speculative science, but a powerful one nonetheless. It takes an explanatory approach, not just a descriptive one, trying to answer the ultimate question of why we are the way we are. So the evolutionary psychologists explain that we have sugar cravings because carbohydrates were rare on the savannahs of Africa where the modern human brain evolved. A rule of thumb that was adaptive in one environment (if you happen to find sugar, eat as much of it as you can) turns out to be maladaptive in an environment where Coca-Cola is practically in the water supply.
These two stories are intriguing ones, and there's much to be learned from both approaches. But neither story tells you something about your own present-tense experience that you don't know already. You're already familiar with your sugar cravings, and while it's nice to learn about their origins, knowing the role of the dorsal striatum won't help much the next time you're salivating over that Mars bar. If science is going to tell you something useful about your brain, it has to go beyond simply explaining the roots of some familiar mental phenomenon. Your brain is filled with a lively cast of characters sharing space inside your cranium, and while it's interesting to find out their exact addresses, that information is ultimately unsatisfying. Call it the "neuromap fallacy." If neuroscience turns out to be mostly good at telling us the location of the "food craving center," or the "jealousy center," then it will be of limited relevance to ordinary people seeking a new kind of self-awareness — because learning where jealousy lives in your head doesn't make you understand the emotion any more clearly. Those neuromaps will be of great interest to scientists, of course, and doctors. But to the layperson, they'll be little more than trivia.
The best that the brain sciences offer comes in the form of genuine insights, insights in both senses of the word: a looking within and a new way of understanding. To that end, I have applied a test of sorts to the stories I've assembled for this book. I call it the "long-decay" test — as with a sound wave that takes an extended time to trail off into silence (or a radioactive material with a long half-life). There are insights about the brain that prompt a quick burst of recognition — "So that's where the food craving comes from!" — and then just as quickly fade in the mind. These insights fail the long-decay test — they don't stick with you in any profound way. To pass the test, the insight has to reverberate for weeks or months after you've first encountered it; it has to pop up in conversation or in moments of self-reflection; it may even change your behavior based on what it teaches you about yourself. Long-decay ideas transform as much as they inform.
For the most part, the long-decay ideas I've assembled here have direct relevance to ordinary minds, minds untroubled by the extreme conditions profiled in so much of the scientific literature: amnesia, Parkinson's, Alzheimer's, manic-depression, the many forms of aphasia. The most powerful theories of mind have always had something useful to contribute to generally healthy minds and not just troubled ones. Freud developed his theories partially by analyzing the debilitating disorders of hysterics and schizophrenics, but psychoanalysis ultimately attracted such a large audience because you didn't need to be mentally ill to find something useful in it. You could explore your Oedipal complex and analyze your dreams even if you weren't worried about your sanity. I believe modern neuroscience deserves to be seen the same way: as relevant to the healthy as it is to the ill, as relevant to those of us wrestling with the small triumphs and tragedies of everyday life as it is to those battling more forbidding demons.
Enough disclaimers. I've tried to write what follows not as a polemic or a broadside, but as a kind of appreciation. Think of the way an art historian or a musicologist can help you discern new qualities in a great painting or symphony; your perception widens when you look through their eyes or listen with their ears. Brain experts can help us do the same with our own mental life. Under their tutelage, we start noticing reflexes and patterns hitherto invisible to us. Knowing something about the brain's mechanics — and particularly your brain's mechanics — widens your own self-awareness as powerfully as any therapy or meditation or drug. Brain science has become an avenue for introspection, a way of bridging the physiological reality of your brain with the mental life you already inhabit. The science and technology today are no longer limited to telling us how the mind works. They also have something to say about how your mind works.
Unlike so many technoscientific advances, the brain sciences and their imaging technologies are, almost by definition, a kind of mirror. They capture what our brains are doing and reflect that information back to us. You gaze into the glass, and the reflection says to you, "Here is your brain." This book is the story of my journey into that mirror.
Copyright © 2004 by Steven Johnson
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