by Mark Pagel
Still, there is reason to believe that humans are still evolving, and the reasons come back to our brains: the real message of our evolution is written into our responses to the cultural changes our brains have unleashed. HAR1 will almost certainly prove to be just one of many genes affecting the structure and organization of our brains. Two that have already been identified are ASPM and microcephalin. A variant form of microcephalin that arose 37,000 years ago is currently sweeping through human populations. The timing of its probable origin corresponds to the full flowering of culture in fully modern humans. A variant of the ASPM gene, also sweeping through human populations, arose just 5,700 years ago, coinciding with the spread of agriculture and animal domestication, the development of cities, and early writing. Its remarkably young age implies that the human brain is still evolving and evolving rapidly. If you are of European, Middle Eastern, or Far Eastern descent, including Iberians, Basques, Russians, North Africans, and South Asians, chances are you have this variant in your brain. But if so you should not conclude that you have higher intelligence—the variant form might simply confer some sort of metabolic or energetic difference. No one yet knows.
Beyond brain genes, genes that affect the size of our teeth and jaws and genes related to our appearance and attractiveness to others are still evolving. Even where we don’t have direct genetic evidence, there is good reason to expect that as we change the nature of our society, many new kinds of abilities will be favored, and this will drive new trends in our evolution. The ability to concentrate for long periods, as is required of many workers who use computers, or as is increasingly asked of school-age children, might be one such trend. Language and communication abilities continue to grow in importance as more and more of our business is about trades and exchanges. The number of children someone produces is statistically linked to their wealth, and so if there are any genes that might be related to temperaments or abilities that affect our earning power, those genes will be evolving. Current trends among women to have children later in life will favor women with a genetic predisposition to delay their menopause.
Crime has been falling steadily for at least 1,000 years, and we have every reason to believe that it has been falling for the last 10,000 years, or ever since we began to live in larger communities. Remarkable statistics kept for the last millennium in the United Kingdom show that crime rates have declined throughout that period, and have shown especially sharp drops at periods in history when militias or other gun-bearing groups have been disarmed. Just as there is selection for tameness in the domestication process of wild animals, modern society has increasingly selected against excessively aggressive people within communities. Violent and antisocial people are increasingly being pushed to the margins of society, where they have fewer job prospects and fewer opportunities to reproduce. They may be put in jail, or even executed. The world can sometimes seem a violent place, but we are steadily becoming a more democratic and peaceful species, more cooperative, kinder, more empathetic, and more generous, descended from more aggressive ancestors in our not-too-distant past. We are still being tamed by culture, and if there are genetic differences among us that map onto these more peaceable natures, they will be finding favor in our ranks.
Part III
THE THEATRE OF
THE MIND
* * *
Prologue
PART II SHOWED US the complex network of social relationships, alliances, reputations, and identities that make the cooperative venture of human society work. But those chapters ignored an opportunity that lurks in the background of our cooperative societies. That opportunity is to manipulate them to serve us just that little bit better than average, to somehow get a bit more than our share of the spoils. How have our minds been structured to do this, especially as other minds will be trying do the same as ours?
Before we can begin to answer these questions, we need to confront the greatest mystery of our minds, and that is consciousness itself and just who or what is in charge of it. For most of us, our day-to-day existence is taken for granted and led by an actor we know well. The actor is us, the “I” that is doing the speaking when we say, “I did this,” or, “I did that,” the “me” that we see when we peer inside our minds, and the “you” that is reading this text. If you are like most people, your connection to your inner self is so intimate that it defines you—you cannot imagine yourself as someone else, and you never go away (even though sometimes you might wish you did), except perhaps when you are asleep.
Remarkably, there is reason to believe that this part of our self, this “I” or “me,” is something of an illusion. The great eighteenth-century philosopher David Hume, thinking about personal identity, wrote that “for my part, when I enter most intimately into what I call myself, I always stumble on some particular perception or other, of heat or cold, light or shade, love or hatred, pain or pleasure. I never can catch myself at any time without a perception, and never can observe any thing but the perception.”
What Hume had stumbled on was the realization that he could not find a “watcher”—no homunculus residing in his brain summoning the next perception or idea; no self that was independent of his thoughts. He concluded that we
are nothing but a bundle or collection of different perceptions, which succeed each other with an inconceivable rapidity, and are in a perpetual flux and movement… the mind is a kind of theatre, where several perceptions successively make their appearance; pass, re-pass, glide away, and mingle in an infinite variety of postures and situations… . The comparison of the theatre must not mislead us. They are the successive perceptions only, that constitute the mind; nor have we the most distant notion of the place where these scenes are represented, or of the materials of which it is composed.
Hume’s ideas can be difficult to accept. Are we really just a collection of different perceptions that come gliding along into our minds, and if we are, who or what decides what gets presented? Our perception of consciousness or what it means to have a mind is that there is precisely a sort of inner screen on which our life plays out, and that “we” are there not merely to watch it but to control what gets played on it. But we now know that Hume’s instincts were right: there is no central place where our brains collect up all our thoughts and present them for “you” to watch. If there were an inner “you,” then that you would also have to have an inner you, and so on, ad infinitum. For no less a giant of European philosophy than Immanuel Kant, Hume’s ideas on the mind and metaphysics were enough, in Kant’s own words, to break “my dogmatic slumber.”
There is a proposal from modern brain-imaging studies that would have interested Hume, and forces us to take seriously the idea of our minds as a place “where several perceptions successively make their appearance; pass, re-pass, glide away, and mingle in an infinite variety of postures and situations.” It is that even at rest our minds are not merely blank, springing into action only when something requires their attention. Rather, our minds spontaneously engage in what has been called “stimulus-independent thought.” They naturally wander, flitting from one thought to another with fluidity and ease, and without being “asked,” as if their default setting is to be busy and occupied. Who or what is causing this, and for what end? No one really knows, but regions in the brain’s cortex that cause this activity have been identified. Stimulus-independent thought might be why our minds daydream, rather than merely going into idle when we are not using them, like the impression we might get of a cat sitting on a windowsill with its eyes slowly falling shut. Stimulus-independent thought might be why we are easily bored, do crossword puzzles and brain-teasers, play chess, read books and visit art galleries, watch films, play or listen to music, or even just draw circles in the sand or toss stones into the air if only to see how they fall. Stimulus-independent thought might also be why we dream and could be a reason why some people suffer from insomnia.
It is as if our minds have appetites for thinking, and this might be just what we expect of a mind
that rides inside a body that has a vastly greater capability for changing its world than does the body of any other mind. On the other hand, some might speculate that our stimulus-independent thought is merely a byproduct of thoughts vying for our attention. This is not the radical idea it might sound. Ideas have to compete for space in our minds, and those best at somehow making their way into our consciousness will have a much higher chance of being transmitted to some other mind. It could even be that these “selfish” ideas created consciousness itself as a way of getting us to tell others about them. What appears as a region of our brain that acts independently of our thoughts—the part of our brains responsible for stimulus-independent thought—might just be a launch platform they created.
But it is doubtful this is the whole story of the contents of our minds. Stimulus-independent thought might provide the raw input to Hume’s theatre, but the idea of natural selection, that the fittest survive, may help to frame its contents. Writing in 1995, Richard Dawkins called our attention to the fact that “not a single one of our ancestors was felled by an enemy, or by a virus, or by a misjudged footstep on a cliff edge, before bringing at least one child into the world.” Dawkins’s simple but compelling point was that we inherit our genes from a long line of survivors—and not from those who lived alongside our ancestors but failed to survive; there is real selection in natural selection. It is why the current generation of survivors have genes that are good at making bodies: over many generations, natural selection has concentrated into the survivors’ bodies genes that make bodies good at surviving. It is why our hands and feet, eyes and ears, are so good at being hands and feet, eyes and ears.
Natural selection, weeding out the survivors from the non-survivors, is also why brains are so good at being the central processing and relay centers of our bodies. But while other animals have brains and they think, it is our conscious awareness, that self-reflective sense of self, that we think sets us apart. A dog sitting at the base of a tree, peering up into its branches, might be thinking that there is a squirrel up the tree, but we don’t believe it is having the thought, “I think there is a squirrel up there.” Dog owners will disagree with this remark, but try this out with your dog. Drive a stake into the ground and then another maybe 20 feet away. Put a long leash on your dog and tie one end of it to the first stake. Then loop the dog by its leash around the second stake so that it is facing back toward the first. Now put a plate of food just out of reach. People who study animal behavior call this “the detour task.” Experiments show that your dog will strain and strain against its leash “thinking” that if it just pulls harder it will get the food.
Most dogs do eventually work out what to do, but a dog that was “having thoughts” about its predicament would solve the problem immediately, as we would expect of a human set this task. So to Dawkins’s list we can tentatively add that not a single one of our ancestors’ perceptions—in Hume’s broad sense—let them down. None of our ancestors was felled by misperceiving “heat or cold, light or shade, love or hatred, pain or pleasure.” But we can also add to this that none of our ancestors failed to survive from misjudging an opponent’s rage, misunderstanding the collective mind of their group, by failing to communicate their own intents, needs, or desires, or by misunderstanding these in others, not at least before bringing a child into the world. Our social and psychological framework, even the broad outlines of our aesthetic and religious preferences, may have been molded this way. It is easy to dismiss this contention as unimportant in our modern world, but that is not the world in which our minds evolved. That world was one, to paraphrase John Irving in The World According to Garp, with an “undertoad,” and in which “the dog really bites.”
Still, I say “tentatively” in the preceding paragraph because some may wish to exempt our conscious minds from any sort of control or shaping, allowing us “free will,” or the ability to think about what we want to think about, when we want to, and why. But this may be to ask the wrong question or expect too much. What we want to ask of our minds is what someone with a conscious mind who wanted to be a survivor would use that mind for, and how would they use it. Returning to Hume’s notion of a theatre, then, we can ask just what will appear in it. The answers are the topics of chapters 8 and 9, but we can anticipate them in a general way. We should see that our minds are especially finely tuned to manipulate social systems for their own ends because that is how they will reap the most benefits. But remember, if our mind is a theatre, you might have less control over its contents than you think.
CHAPTER 8
Human Language—
The Voice of Our Genes
That our language evolved because we are the only species
with something to talk about
SOMETHING TO TALK ABOUT
YOU POSSESS the most powerful, dangerous, and subversive trait that natural selection has ever devised. It is a piece of neural-audio technology for rewiring other people’s minds. You have a way to implant thoughts and ideas from your mind directly into someone else’s mind, and they can attempt to do the same to you, without either of you having to perform surgery. Instead, natural selection has equipped you with an apparatus for producing action at a distance. It is not a roar or a bark, but something far more sophisticated. It is your language, of course; its apparatus is your brain and vocal cords and its medium is sound waves that travel through the air. When you speak you are using a form of telemetry, not so different from the remote control of your television; it is just that your language relies on pulses of air pressure rather than pulses of infrared light. Just as we use the infrared device to alter some electronic setting within a television so that it tunes to a different channel that suits our mood, we use our language to alter the settings inside someone else’s brain in a way that will serve our interests. Language is your genes talking, getting things they want.
Language’s subversive power has been recognized through the ages in censorship, in words you cannot use and in phrases you are not allowed to say. According to the Bible story of the Tower of Babel, early humans developed the conceit that by working together they could build a tower that would take them to heaven. God, angered at this attempt to usurp His power, destroyed the tower, and to ensure that it would not be rebuilt he forever confused the people by giving them different languages. Even today, saying the wrong thing at the wrong time or place can get you accosted, thrown into jail, or even killed, and all because of a puff of air emanating from your mouth. Our training in the arts of using this powerful instrument starts early on. Imagine the amazement in the mind of a child when it first discovers that just by making the right sound or sequence of sounds, it can get objects, as if by magic, to move across rooms, and into its hands, or maybe even into its mouth.
We instinctively recognize that our language is unique among all forms of biological communication, but what do we mean by that? All animals communicate, but humans are the only animals with language. Human language is distinct in having the property of being compositional: we alone communicate in sentences composed of discrete words that take the roles of subjects, objects, and verbs. This makes our language a digital form of communication as compared to the continuously varying signals that typify the grunts, whistles, barks, chest-thumping, bleating, odors, colors, chemical signals, chirruping, or roars of the rest of life. Those familiar sights, sounds, and smells can only be more or less intense, or more or less persistent. They might signal an animal’s status, or intentions, or indicate its physical prowess; they might tell a predator it has been spotted, or send a message to nearby relatives of an imminent danger. But lacking subjects, verbs, and objects, these acts of communication do not combine and recombine to produce an endless variety of different messages.
Thus, your pet dog can tell you it is angry, and even how angry it is, but it cannot recount its life story. By comparison, we can use our language to look into the future, share the thoughts of others, and benefit from the wisdom of the past. We can make plans,
cut deals, and reach agreement. We can woo prospective mates and warn off our enemies. We can describe who did what to whom, when they did it, and for what reason. We can describe how to do things, and what things to avoid. We can express irony, surprise, and glee, worry, pessimism, love, and hate or desire. We can be witty or grave, we can be precise or deliberately vague.
No one knows when the capacity to communicate with language evolved, but we can narrow the range of possibilities. Our closest genetic relatives the modern chimpanzees cannot speak, but we can, and so this tells us that language evolved sometime in the 6 to 7 million years that separate us from our common ancestor with them. H. habilis and H. erectus skulls reveal the impressions of two slightly protruding regions of the brain—known as Broca’s and Wernicke’s areas after their discoverers—that neuroscientists have identified as being involved in speech, at least in humans. This had led some researchers to suggest that a capacity for speech, even if perhaps a rudimentary one, might have existed 2 million or more years ago. But Broca’s and Wernicke’s areas are also enlarged in some apes, so their presence is not by itself a trustworthy indicator that a species had language. There is also no evidence to suggest that these early Homo species had anything even remotely close to the complex societies, tools, or other artifacts that we recognize as fully human.
A question that excites great differences of opinion is whether the Neanderthals spoke. This excitement has been fanned by the recent discovery that the Neanderthals had the same variant of the segment of DNA known as FOXP2 that we do, and that has been implicated, among many other effects, in influencing the fine motor control of facial muscles that is required for the production of speech. But, just as was true of Broca’s and Wernicke’s areas in H. habilis and H. erectus, having the same variant of FOXP2 as modern humans do doesn’t tell us that the Neanderthals had language—they might have but, as we have seen in earlier chapters, we cannot conclude that they did on the basis of this short segment of DNA.
