While there is evidence that we have special neurons whose specific job is mirroring, that evidence has not reached the preponderance level necessary to claim a discovery—at least to a jaded physicist. For us, within the pages of this book, it doesn’t matter whether mirror neurons really exist because whatever we have in our brains is doing plenty of mirroring. The alternative to mirroring is called mentalizing. Mirroring or mentalizing, whichever mechanism turns out to be closer to the truth won’t affect our conclusions, so let’s just call it mirroring.
One suspects, wink-wink, that mirroring might have something to do with, nudge-nudge, the popularity of pornography. You know, maybe.
3.4.1 Theory of mind
Have you ever wondered if you thought it all up? Could the entire universe be a figment of your imagination? Maybe nothing exists beyond your thoughts. If so, I appreciate you thinking of me.
Solipsism is sort of half true. You exist only in this dream world of my imagination. I hope you don’t find this offensive. Or, I should say, I hope my model of you doesn’t find this offensive.
In its circularity, solipsism is an airtight, useless philosophy. People who experience solipsism lack many things, including a theory of mind.
Your theory of mind is simply your belief that I have thoughts, that my brain, encapsulated in this bony shell atop my animated corpse, experiences the world more or less the same way that you do. It should really be called your theory of other people’s minds. Children develop their theories of mind by age three, about the time they start forming long-term memories; the two phenomena may or may not be related. Some studies indicate that our theories of mind emerge around eighteen months, about when we learn to talk.
Ultimately, having a theory of mind boils down to the legitimacy of a statement that we make all the time: “I know how you feel.”
Consider that statement.
Our models of the world have to be similar enough for us to agree on pretty much all factual information. Red is red, after all. Maybe what you and I see differs, but we agree it’s red.
But feelings?
It’s as if we can read each other’s minds. How often do you interrupt someone mid-sentence because you know what they’re going to say? I get you; I know where you’re going. Sometimes we misunderstand, but more often than not, we experience empathy that is all but indistinguishable from mind reading; mind reading that is the mirroring of emotions.
When we detect each other’s perceptions, reactions, biases, and assumptions, as well as emotions—whether through body language, facial expression, or perspiration—we react to it, at least partially, as though we are sharing that experience. We express, we sweat, and we think. And we mimic each other. That reaction is fed back through the thalamus and on through the whole chain.
3.5 SENTIENCE AND CONSCIOUSNESS
Sentience means being aware and capable of acting on sensory input. Consciousness means worrying about being aware.
The continuing interplay of billions of processes feeding patterns up and down, forward and backward is at once the cause and experience of consciousness. Or at least, that’s the best explanation that neuroscience has right now. The trick is not to think of all these simultaneous processes, some synchronous and some asynchronous, and how they emerge into something so unlike themselves, but to keep in mind the constant rush of new data that has to be processed even as the slightly earlier data are processed and the still-earlier data are processed. Consciousness does not exist independent of time’s passage.
Perhaps the single most acute indication of consciousness is the realization that it is inextricably the experience of time passing, and that someday it will end.
3.5.1 Consciousness threshold
How much bottom-up thinking is required to generate top-down thinking?
When you boil water, you heat it until it reaches a critical temperature, the boiling point, at which time it becomes steam, a transition from one state to another. The universe is packed with phase transitions like water to steam, ice to water, quick to dead—shifts between states that have quite different properties.
Most neuroscientists believe that consciousness emerges when the accumulation of bottom-up processes surpasses a threshold of complexity. The idea is that there is a point where the interactions of bottom-up processes reach a complexity threshold—like a boiling point—and the simple electromechanical processes of interacting neurons make a transition—liquid turns to steam—and consciousness emerges.
Of course, no one knows for sure.
The three different levels of consciousness consist of sentience, primary consciousness, and higher-level consciousness, distinctions that follow the evolution of the brain from your inner frog to your inner puppy to your inner Feynman.
Sentience means being capable of processing and responding to sensory input. Frogs, lobsters, and fish are sentient. Even trees and plants respond to external conditions, albeit on different timescales, so let’s put them into the sentient bin too.
Mammals, like dogs, apes, dolphins, deer, mice, and cows, as well as birds, especially the uncannily clever crows, ravens, and parrots, show every sign of having primary consciousness. All these animals create realities for themselves and perform some level of planning on a timescale of at least several seconds. But are they aware that they are aware? Do they have higher-level consciousness? Do they worry?
3.5.2 Consciousness spectrum
Instead of a threshold, maybe consciousness is a continuous property that varies in degree, like the continuous increase in temperature of water from cold (33°F, 1°C) to hot (211°F, 99°C), rather than the transition from liquid (at 212°F, 100°C) to steam (still at 212°F, 100°C).
Instead of big jumps from unconscious rocks to sentient plants to reactionary reptiles to primary conscious mammals to higher-level conscious people, let’s entertain the possibility that consciousness ranges from the experience of plants like General Sherman that have no neurons and presumably nothing resembling consciousness, to people, with every creature appearing somewhere along that continuum.
Perhaps this consciousness spectrum is ordered by brain size—after all, complexity increases with the number of processors. More processors mean more neurons, and more neurons mean a bigger brain. Ordering by brain size puts people well to one side of the spectrum but below many animals including elephants, killer whales, and sperm whales, who have the largest brains of all.
The standard approach to gauging the intelligence of a species, going back to Aristotle, is to use the “encephalization quotient”— jargon for the ratio of brain weight to body weight. The idea is that a big animal needs a bigger brain to handle its big body, so the excess size doesn’t mean that the big-brained, big-bodied animal would be smarter than a big-brained but smaller-bodied animal. Humans win the brain-weight-to-body-weight ratio competition.
Self-awareness indicates consciousness. If you recognize yourself as yourself, then you’re probably aware of your awareness. Put a red mark on the nose of a baby and then put her in front of a mirror. Between six and twelve months old, she’ll respond to her reflection as if it were another baby. From twelve to twenty months, she’ll find the image a bit confusing and might reach out to touch the mark on the reflection’s nose or avoid the reflection altogether. At right around twenty-four months, the baby sees herself, notices the mark, reaches up to her own nose, and wipes it off. Mature elephants, dolphins, orcas, and many birds also pass this so-called rouge test.
Dogs don’t usually pass the rouge test. Vision is the primary sense for people, elephants, and birds, but dogs rely more heavily on scent. Of course, dogs recognize their reflections in the smell of their own pee, fur, and bedding. How many times have you seen a dog stop to sniff a fire hydrant? Like checking the sign-in sheet as you walk into a meeting, dogs like to know who has walked through the neighborhood and like to sign in themselves too.
My favorite way to approach the idea of a consciousness spectrum is to use information theory
, but then I’m kind of a geek, so it figures that I’d like a mathematical approach. Information theory comes from thermodynamics, the physics of order and entropy. Neuroscientists Gerald Edelman, Giulino Tononi, and Kristof Koch calculate a quantity called integrated information to determine the level of organization of a whole and compare it to the sum of the organization of the parts—a quantitative way of answering whether or not a whole really is greater than the sum of its parts.
The idea of integrated information is that the difference between the organization of your neurons and the organization of what emerges from your neurons is the amount of consciousness you experience. Integrated information leads to a spectrum that allows for any organized group of inanimate objects, like neurons, to experience consciousness. So far, there is no unambiguous way to measure the organization of your brain or your mind, but they’re working on it.
More likely than either a threshold effect or a continuous spectrum, consciousness probably emerges in different amounts in multiple steps, rather than either a smooth slope or a single giant leap. This moderate position follows the incremental complexity of brain evolution—brainstem to limbic system to neocortex—without neglecting that the whole system is rewired and re-optimized at each stage of that evolution for every critter.
The question then becomes: What states of awareness lie between sentience and consciousness and what might lie beyond?
I’ve conveniently overlooked the role of language in our ability to elucidate our thoughts not just to each other but to ourselves. Maybe the ability to formulate thoughts in a structured way gets us over the threshold to high-level consciousness. We’ll return to this later.
3.6 FREE WILL
Can you choose what to do with the information that percolates into your consciousness?
Are you free to choose to toss this book aside? Maybe have a nice book burning? Wait! Don’t do it! Please come back. Of course you can make that choice.
Or is that choice an illusion?
We saw in chapter 2 that lots of decisions are made by bottom-up processes before we become aware of them. Your inner Feynman had nothing to say about whether or not you ran away from the saber-toothed tiger. Piles of experimental evidence show that trivial decisions occur before you’re conscious of them.
Does the evidence that we make decisions from the bottom-up rather than the conscious top-down indicate that our free will is an illusion? Many neuroscientists reject free will in favor of a deterministic view of choice. That is, instead of being free to will a decision, we seem to be driven by bottom-up processors to make decisions without the conscious will to alter them. Perhaps the illusion of choice is a mechanism for making sense of the world, just another association of disparate memories and instincts providing impetus to act.
The whole feed-forward/backward loopiness of emerging consciousness and hanging around in bars with your mom is chaotic. You kick a normal football and it goes through the goalposts. If you kick it a tiny bit differently, it will still go through the uprights. But if you kick a chaotic football just the tiniest, teeniest bit differently, it goes straight up or backward; it’s chaotic and that means we can’t predict where it will go.
Your brain is chaotic too.
Thirstiness boils up to consciousness, and you decide—whatever that means—to go to a bar, try a new beer, watch some TV, maybe exchange a few wisecracks with other humans. Your bottom-up initial conditions include things like where you place your feet, how you hold your head, and the trillions of your other miniscule attributes as you enter the bar. If your path happens to guide you past someone drinking a piña colada and your head is positioned such that you get a whiff of the coconut, it could change your mind. You’re thirsty, after all, and you haven’t had a piña colada in a while, so your top-down consciousness starts firing the possibilities down to your processors, including your taste buds, and you start jonesing for a fruity rum concoction. That desire percolates up and a mai tai sounds even better, and the best mai tais are a few blocks down the street at the tiki bar! You turn around, go to the tiki bar, start drinking rum, hit it off with the bartender, whom you eventually marry, and never realize that your mom was sucking down scotch and arguing politics at the bar you left the night of the world-changing mai tai.
We can all point to tiny events, miniscule changes in the conditions of our lives that led to large differences in where we are and how we got there. A while back, we ran into the deeply interconnected circular process of how we create a coherent, single reality from the constant stream of sensory input. The picture-in-a-picture-ness of that process consists of a large number of tiny effects, most of which have a tiny impact, but a few of which, like getting a waft of piña colada, have large consequences. It’s called the butterfly effect—the idea that a butterfly flapping its wings in Fontana can cause a tornado in Tulsa.
Assume for the moment that you do not have free will.
The fact that your brain is a chaotic biochemical machine, and the fact that it is fundamentally impossible to measure the complete state of that biomechanical machine with perfect accuracy at any time—after all, nothing can be measured with perfect accuracy—means that it is impossible, not just improbable, but impossible, to predict your behavior.
Adding it all up, there is no way to determine whether or not you have free will; therefore, you are an indeterminate animal who either has free will or the precise equivalent.
And so is your dog.
3.7 THE ESSENTIAL WEIRDNESS OF DEATH
We’ve all lost friends and family to the inevitable end of their consciousnesses.
No matter how short or long the process, whether dead from some immediate cause that gave no warning or dead after a drawn-out struggle, the weirdest thing about death is the sheer on/off of it. How can someone switch from being a thinking thing to being a nonthinking thing?
The insanity that a thinking being could exist one minute and be meat the next, the essential weirdness of death, comes from the way we build our realities.
The person you knew was a model of the actual person you had in your brain. If wisdom is to know others and enlightenment is to know oneself, then wisdom and enlightenment are worth pursuing but are also goals that can never be obtained. We’re too dynamic. The instant you attain enlightenment, you change. It’s like trying to pick up a watermelon seed; as soon as you get a grip, it spurts away. Do you know someone, really know her?
Look at figure 10. The circles on the left of each pair represent your models of a person and those on the right represent who he really is— his character, opinions, abilities, faults, quirks, everything about him. In (a), you’ve just met. Your model of this guy is built from your expectations that is, from patterns that your bottom-up processors assemble from his physical appearance, his T-shirt, what he’s drinking, whom he’s with, what you may have heard about him from other people, and on and on. Those prejudices are fed forward and, just below your high-level consciousness, you assemble a model of what to expect from him. The overlap of the two closed curves measures your model’s accuracy.
As you get to know each other (b), your model grows more accurate; some of your prejudices were right and some were wrong. Eventually, in (c), there’s pretty good overlap between your model and the actual person. Good friends know how each other responds to politics, religion, music, and beer; they know how and when they can rely on each other.
Figure 10: A graphic version of the process of coming to know someone: (a) just met, (b) getting to know each other, (c) an old friend.
Bring your best friend to mind right now. Picture her. Pretty easy, isn’t it? Now ask her if she’s read this book. You probably don’t know for sure but pretend that she says yes. Now ask her opinion. You have a pretty good idea of what she would say, don’t you? You can even gauge what she liked and didn’t like and why she read it in the first place. At this stage of your interior dialogue, you start a little internal banter, exchange inside jokes, or argue with each other.
/> She’s not there, but the model of her is still in your head. That disconnect between your internal awareness of this person and the external reality that she’s not there is weird enough when the person you’re thinking of is alive. It goes off the rails when you think of someone who’s dead.
When someone close to you dies, even a dear pet, it is literally incomprehensible that this person is dead, gone, demised. Yes, literally incomprehensible because the model of this person in your mind did not die. The model didn’t even change; it stopped changing. And that’s the disconnect that brings the painful dissonance.
You think of the dead person the same way that you did when she was alive, right up until that jolt of reality comes back and you remember that your friend is gone. If you’re religious, your faith might provide an attachment to that model, a heaven-sort-of-thing where you can imagine your friend as you did when she was alive. Whether or not it’s true, that religious attachment is yet another pattern, a model you construct in your brain.
When someone dies, their experience of time passing ends, but your experience of them doesn’t.
3.8 GOOD, FAST, OR CHEAP: PICK TWO
We are model-building, pattern-recognizing predictors—which makes us lazy bigots. It’s as though Mother Nature said, “You can be good, fast, or cheap—pick two,” and natural selection said, “We’ll take fast and cheap.” In biological terms, cheap means efficient.
You learned the sound of your mother’s voice before you left her womb. You had to learn most patterns, but you came out already able to recognize nipples. Booting up a brain takes years because you need a trove of patterns in order to think. You have to break a few neurons to get your first few patterns. In the next chapter, we’ll figure out how babies’ brains adapt to the initial onslaught of reality.
The Left Brain Speaks, the Right Brain Laughs Page 7