The Accidental Species: Misunderstandings of Human Evolution

by Henry Gee

  If language isn’t uniquely human, either in its function or its complexity, what about writing, the recording of language in symbolic form outside the body, such that it can be preserved and disseminated far more widely than spoken language ever can? Because of writing, we no longer have to learn everything anew in each generation, or rely on oral tradition that disseminates slowly, is prone to error, and can be conveyed to only a few people at once.

  Isn’t writing—and, by extension, the power of writing to address many people at once—the key to the current domination of the earth by humans? Well, perhaps. Except that many animals use such extracorporeal forms of communication, and many of these animals have little in the way of language, and perhaps less of brains. One thinks of the pheromone trails of ants, or the urine trails of voles—and these are just two examples of extracorporeal communication and reporting that we know about.

  A more philosophical problem is recognizing as representational any signs or actions made by other creatures. How do we know that the architecture of termite nests isn’t random, but a purposeful inscription of their history? This idea might seem outrageous, but a current problem in anthropology is learning how to recognize whether scrawls made by early humans were just inchoate doodles or deliberate records left by inquiring minds.7 And if such things are hard to judge for members of our own species, we can have little hope that we might recognize, still less decipher, any form of extracorporeal communication left by other animals.

  I contend, however, that at least some extracorporeal forms of communication are just that—representational—in that they contain particular meanings that are there to be interpreted by others of the same species once the author has left the scene. The example is, however, personal and anecdotal—because I have personal experience of it on a daily basis—and that is the intensely odoriferous imagination of dogs and the ability of dogs to leave messages to be interpreted by other dogs without direct dog-to-dog contact.

  Most days when I take my dogs out walking, it’s not the exercise they seem to crave, but the social stimulation. An invitation to go for a walk is greeted with intense excitement—much barking, wagging of tails, and general jumping up and down—but a gentle amble of less than two miles leaves them completely exhausted. It’s the social stimulation, I think, that saps them—not the actual physical exercise. Every few steps we stop so that the dogs can sniff what seem to them to be interesting blades of grass, lampposts, walls, tree stumps, and so on. They sniff with the deliberation of master wine tasters, and, sometimes, mark the site with small urine samples of their own. To me, the human observer, it looks just as if they are sampling the status updates of other dogs on their doggy social network—let’s call it SniffBook—and perhaps leaving their own comments. We humans have a very poor sense of smell compared with that of dogs, so we cannot appreciate the refinement, the nuance, the bouquet—the meaning—of the scents the dogs are exchanging, but given what we know about gossip in general, and the importance of social networks, we can have a good guess. The dogs are trading information about who’s who, who’s been around, who has said what to whom, and, perhaps most of all, their state of health. We humans do it through vision, language, and sound—dogs do it through smell. The modality is different, but the end result is just the same.

  I live on the very picturesque coast of north Norfolk in England, which is great dog-walking country. Being proverbially flat, it’s perfect for an easy ramble. The beaches are vast and deserted; the skies are enormous and dramatic. One morning my wife had arranged to meet with two friends for a walk, and she asked me to drive her and our dogs to a cliff-top rendezvous, whence they’d make their own way home. Her friends were there, waiting, with their own dogs, as we arrived. As I drove away, I was much taken by the scene in the rearview mirror. A meter and a half above ground level, the humans were talking animatedly with one another, mouths moving, hands waving—a meter below that, the dogs were greeting one another with equal enthusiasm, with much sniffing of bottoms and wagging of tails. Without being distracted by the words uttered by the humans, it seemed to me that the behavior of humans and dogs was all but identical irrespective of the mode of communication. I felt like the animals at the end of George Orwell’s Animal Farm, peering through the window as the pigs and the farmers feast convivially inside, looking first at the pigs, and then at the farmers, and at the pigs again, and finally not being able to decide who was who.

  11: The Way We Think

  So much for bipedality. So much for large brains, technology, intelligence, and language. There might—just might—be one ability, one trait, that marks us out as special. We human beings, surely, differ from other animals in that we are conscious.1 That is, we are aware of our actions and their consequences, having the ability to imagine ourselves as participants in the drama of our own lives, and how our lives interact with those of others.

  I find the term “consciousness” rather vague, and so the effort to understand it is as challenging as trying to nail jelly to the ceiling. I prefer “self-awareness,” the meaning of which is self-explanatory: that we have a sense of “self,” as if we are a whole, cohesive entity, inhabiting a body. In this book I use the term “sentience” rather than “self-awareness,” because it is shorter and more elegant, but my meaning is precisely the same. A sentient being will be aware of itself as a character in the drama of its life, and thus aware of the consequences of its actions on others, and to some extent of the internal mental states of the other characters. Psychologists might say that sentient beings have “a theory of mind.”

  Art, religion, even science, spring directly from this sense of self. Sentience brings along with it the crushing realization of the brevity of life, the inevitability of death, and through that, a desire to investigate and explain the human condition.

  The poet John Keats knew all about this, perhaps better than anyone. As a young apothecary in early nineteenth-century England, the business of disease, debilitation, disfigurement, and death was part of his daily round. He saw his relatives and friends sicken and die young, mainly from tuberculosis, to which he, too, eventually succumbed. The transience of life was well expressed in his epitaph: “Here lies one whose name was writ in water.” Yet in a desperately short life—he died before he was twenty-six—he created arguably the greatest poetry ever written in English.

  In his great poem Ode to a Nightingale (written in May 1819), he contrasts the pain of a mortal doomed to muse on his lot, with the joy of the nightingale, living ever for the moment and therefore not doomed to death, a concept that would mean nothing to the insentient.

  Fade far away, dissolve, and quite forget

  What thou among the leaves has never known,

  The weariness, the fever and the fret

  Here, where men sit and hear each other groan;

  Where palsy shakes a few, sad, last gray hairs,

  Where youth grows pale, and spectre-thin, and dies,

  Where but to think is to be full of sorrow

  And leaden-eyed despairs;

  Where Beauty cannot keep her lustrous eyes,

  Or new Love pine at them beyond to-morrow.

  But sentience—the luxury of self-knowledge—is in fact not unique to humans, and its presence in other animals can be tested and verified. Clayton and her colleagues have shown that crows modify their behavior in predictable ways depending on the identity, number, and attitudes of other crows in the vicinity.2

  In one experiment, a western scrub jay buries some food in full view of other jays, but will then return when no other jays are around, unearth the cache, and bury it somewhere else. Significantly, the jays that rebury their food in private are those that had been thieves of the caches of others in the past. The conclusion seems clear—the jay pictures itself as a participant in a drama in which it guesses the intentions of other jays close by, which would be to steal its food store. The jay seems to be able to put itself in the minds of its fellows, imagining what it would do in a simila
r situation.3 Sentience is a valuable asset for any social animal, but with sentience comes deceit. It is probably no coincidence that very young children are very bad liars until around the age of three, when they first acquire a “theory of mind” and can put themselves in the shoes of others. By the same token, people with autism-spectrum disorders can have great difficulty in social situations because they have trouble reading the emotional states of others,4 and must learn by intellection what others seem to absorb by instinct. Autism-spectrum disorders might therefore be seen as disorders of sentience.

  Sentience, however, is not an unalloyed benefit . . .

  Hold it right there: how can something that seems so beneficial, so wonderful, that it might easily be seen as the final attainment of humanity, the justification of an exalted place as the acme and purpose of Creation, the final revelatory light that switches on in our minds, from which flows all art, culture, science, and indeed everything that seems to make human life so much richer and more distinctive from that of any other organism, be seen as in any way a disadvantage?

  Well, let’s start with something we all know, and some of us remember with much toe-curling embarrassment: our teenage years. One might interpret the extreme self-consciousness of teenagers, whose brains are undergoing drastic remodeling before the final attainment of adulthood,5 as a disarming and sometimes crippling excess of sentience. Teenagers try to grapple, perhaps for the first time in their lives, with age-old questions—questions such as the meaning of existence, man’s inhumanity to man, and so on—that their parents have long abandoned in favor of more tractable problems, such as the location of one’s spectacles, or the identity of whoever it was that put the Benzedrine in Mrs. Murphy’s Ovaltine.6 It’s perhaps no accident that the greatest artists, poets, musicians, mathematicians, and even scientists tend to do their best work when they are young, when their self-knowledge is at its peak. To paraphrase Tom Lehrer: when Mozart was my age, he’d been dead for fifteen years.

  Everyone who’s been a teenager will have experienced the same agonies of self-consciousness, and will have been relieved, frankly, when that fit’s over. But if teenage sentience can be a handicap, just imagine how difficult life would be, intolerable even, if we were sentient all the time.

  When one is learning a new skill, whether it’s a sport, driving a car, or learning a musical instrument, one is often painfully aware of every movement one makes, and wonders if one will ever get the hang of it. With practice, however, the movements we make as we perform these tasks become automatic, wired into those parts of the brain that do things without our having to be conscious of them.

  That’s why an experienced driver, say, will be able to drive along a familiar route literally without thinking about every turn of the wheel, every press on the gas or the brake, and will be able to take evasive action (such as swerving out of the path of an oncoming vehicle, or applying the brakes before a potential collision) faster than conscious thought would seem to allow. When a driver finishes his journey, he will not be able to recall the precise sequence of actions he took as he drove, as he would were he a computer. A concert pianist will be able to play a complex, learned piece by letting her fingers do the walking with what musicians call “muscle memory,” using the sheet music only as a backup.

  I believe that we live most of our lives in this way. Just as we don’t give conscious thoughts to routine, learned habits such as driving, we do not, as a rule, record in any self-conscious way the moments of our lives as they pass. When you look back at one day lived, you recall a small series of incidents as blurry snapshots, not every single moment as you lived it in exhaustive detail. The vast bulk of the time through which we travel is passed in a state of insentience.

  In fact, I’d go so far as saying that most people live most of their lives without much being troubled by sentience. Is this not a somewhat snobbish attitude? To be sure, you could see it that way, but consider the alternative—and if you do, you’ll see that it is almost too horrible to contemplate.

  The Argentine essayist Jorge Luis Borges did just that in a memorable story called Funes the Memorious.7 Ireneo Funes is a young man who, as a result of a head injury, has perfect recall of every moment of his life. The effect is disabling: because he sees and records in perfect detail, he can no longer categorize objects, for every new thing he sees is unique. For example, Funes is unable to recognize any individual dog as a member of a class of creature called “dogs,” by abstracting those features that all dogs have in common. Funes would have read as meaningless Ogden Nash’s prescription in Introduction to Dogs:

  The dog is man’s best friend.

  He has a tail on one end.

  Up in front he has teeth.

  And four legs underneath.

  Because Funes sees every detail of every dog, he is unable to distinguish between those features that are specific to each dog, and those that belong to dogs more generally. To Funes, each dog is sui generis: so distinct, one from the other, that no categorization is possible.

  By the same token, Funes remembers everything that happens with perfect clarity, and is therefore unable to summarize any one day of his life by abstracting any highlights—to us, the snapshots we remember—as in doing so he is forced to relive each day in real time. Everything in his life is important, and, as a result, nothing is. Incapable of judgment, he is confined to a single room, paralyzed by self-awareness. It seems clear that while sentience has adaptive value for social creatures, one might have too much of a good thing.

  All of the above rests on a single, untested assumption about the mechanics of sentience. To be sentient—to have a “theory of mind”—you must be able to imagine yourself in the drama of your own life, as if you were an actor on a stage along with imagined representations of your friends and relations.

  Now, here’s the thing—if you’re all on this imaginary stage strutting your stuff, who is the audience? The conventional answer is that you yourself are the audience. But to picture that, you have in a sense to be watching yourself watch the drama, in which case there has to be another version of you watching the watcher, and yet another watching the watcher of the watcher, and so on—an infinite hall of mirrors. In the mind’s theater the watchers come and go, toward absurdam, reductio.

  In Consciousness Explained, philosopher Daniel Dennett shows that this image of a mental theater might make a pleasing metaphor, but it is almost certainly not how the mind works. The philosopher René Descartes imagined that the “soul,” or in our terms our sense of “self,” was located in a physical part of the brain (he chose the pineal gland), but no evidence has ever come to light that any physical part of the brain corresponds with this so-called Cartesian theater. There is no central command center, like the bridge of a ship through which lots of little people look out through our eyes as windows, surveying the world and acting on information received. In terms of actual anatomy, rather than metaphor, there is no single part of the brain that processes all incoming sensory information, integrates it, mulls it over, and then instructs the appropriate responses.

  Sensory information does come in, and is processed by various parts of the brain—but the processing is piecemeal, done by several different parts of the brain. Eventually, responses are formed, but again, not in any straightforward way that depends on the inputs. Indeed, the assumption even by trained neuroscientists and philosophers that there must, somewhere, be something akin to the Cartesian theater has led to all sorts of seemingly anomalous research results, perhaps most notably the initiation of a motor action before the subject is “conscious” of taking that action—a result that has led to all sorts of questions about free will.8 The simpler solution—but somehow the harder one to take—is that there is no single center of consciousness. There is no Cartesian theater, no command center, no captain’s bridge. Sentience is an illusion, a kind of running commentary kludged together after the fact, by and for the benefit of lots of different parts of the brain at once. And the brain is eas
ily fooled.

  I am sure you’ve had dreams in which you are involved in epic dramas, dreams with plots that seem to take a great deal of time to unfold, but that end with some tumultuous noise. You awake and find that the noise is your alarm clock. As you stir yourself into wakefulness, you will naturally ask yourself how your brain laid out such a complex drama so that it culminated precisely at the moment your alarm went off. You might say that as you know very well that your alarm is going to go off at (say) seven o’clock—so well that you often wake up at 6:59, just in time to switch it off—then your mental impresario will have started a well-timed sequence of events designed to culminate at that moment.

  But that must be wrong, as there have been other occasions when long, complex dreams have ended with some disturbance caused by a sudden, external stimulus that could not have been predicted. Is your mind a time traveler? Can you see the future? Of course not—your senses respond to the stimulus, but your mind makes sense of it backward, rationalizing it after the fact, giving the illusion of the forward passage of time.

  We are visual creatures, so it’s not surprising that vision has long been the playground of neurobiologists seeking to understand consciousness.9 Light impinges on the retina, causes an electrochemical change in the optic nerve, creating a signal that travels along the optic nerve to the brain, eventually arriving at the part of the cerebral cortex where the signal is processed. Does this raw signal arrive at an imagined version of a movie screening room? Apparently not—the signal is processed in various ways before it gets to the cerebral cortex. What we “think” we “see” is very far from the pattern of photons that hit the retina. The “image” has been cross-referenced with other sensory data and memories of past images, adding meaning. If this weren’t the case, that thieving scrub jay wouldn’t be able to tell the difference between its fellow jays and any other bunch of photons. This idea—that non visual inputs give meaning to a visual image—is a bugbear for researchers into artificial intelligence, who have difficulty getting a computer to recognize that when an object goes behind another object and comes out the other side, the two are in fact the same, coherent object.