Thumbs, Toes, and Tears Page 8

  There are other nonverbal forms of communication. To express dominance in a group, lions or gorillas will charge the challenger, and most times the challenger rolls over on its back, and shows its belly to concede defeat. Horses have a biting and kicking order, just as chickens have a pecking order. The unfortunate horses and chickens that find themselves at the low end of the totem pole accept the abuse. It’s a form of communication that lets every animal in the group know where they stand.

  This unconscious language that bodies speak is as wired into the human race as it is into other species. When physically attacked, our first instinct is to put our hands and arms around our heads, duck, crouch, basically withdraw our bodies from the attacker as much as we possibly can, something scientists call “tactical withdrawal.” It is a form of flight when we can’t actually flee. We have developed other subtle forms of tactical withdrawal from verbal attacks and confrontations, too. We hang our heads, wince, or shrug, for example, all motions that send subliminal signals of a desire to be somewhere else.3

  Evolutionary psychologists theorize that body language evolved as a visceral, external communication of the inner state of the creatures displaying it. It uses the usually unintentional vocabulary of our limbs and muscles to reveal what is on our minds or in our hearts. That is one reason why when we speak with someone face-to-face, our bodies are often holding a parallel conversation with them that can be substantially different from the messages contained in the strings of words we are exchanging. We have all finished a conversation or meeting feeling down or confused or unusually good, not because of anything that was actually said, but because we have subliminally downloaded messages of sadness or deception or joy expressed in the bodies and faces of the people we just met with.

  Darwin wrote about the nonverbal ways both animals and humans communicate in his 1872 book The Expression of the Emotions in Man and Animals. He speculated on everything from what it meant when a cat pins its ears back to the way we turn down the corners of our mouths when we are sad. Seventy-five years after Darwin explored those ideas, anthropologist Edward T. Hall and psychologist Paul Ekman, among others, introduced the world to kinesics, the science of body language, and began to more closely explore the meanings that lay hidden behind crossed legs, licked lips, and raised eyebrows. One study even showed that when we see something we like, not only do our eyes widen (presumably to get a better look), but our pupils do, too, something good poker players keep in mind.

  Our bodies speak at this primal level because the body’s language is ancient. Its messages travel along paleocircuits, nerve pathways that were set in place millions of years before the brain had assembled the hardware used for speech and conscious thought. Some body language, such as shrugging, traces its origin to the motor pathways that existed in the spinal cords of jawed fish that first began to swim Earth’s seas during the Silurian period 420 million years ago. When we push our palms down or straighten our backs and raise our heads in a conversation, we are recapitulating behavior traced to reptiles that developed a predisposed, genetic ability to look larger and fiercer by temporarily rising up on their hind legs.

  Still other studies have shown that lower rates of head nodding during conversation can be associated with deceitful communication. In fact, there are potentially hundreds of nonverbal cues related to deception, from increased blinking to movements such as rubbing our noses or necks or eyes as we speak. If we are suddenly caught off guard in a conversation or find ourselves in a personally uncomfortable position, we might gulp or swallow hard, and bob our Adam’s apple like a yo-yo.

  Even the way we stand in relation to those around us says a lot about whether we feel uncomfortable, threatened, open, or respectful. Our bodies tend to square up with the people we admire.4

  Scientists believe that most body language is rooted in the irreducible basics of a species’ survival—fight, flight, submission, courtship, even disgust with rotten or poisonous foods. Eventually these ancient reflexes evolved into reactions that revealed increasingly complex inner states, such as fear, anger, or personal revulsion. And then those became important forms of communication; ways of saying, “I submit. I’m scared. I’m happy. I want to mate!” They laid the first foundations of communication, which grew more sophisticated as creatures became more intelligent. (The body language of a dog, for example, is more complicated and more telling than the body language of a gecko.) In time, especially with primates, body language engaged new parts of the anatomy to express information and emotion—faces, for example.

  …

  The faces of most four-legged mammals act not as communicators but as weapons. They are the end point of a projectile outfitted with snouts for smelling, eyes for tracking danger, and teeth for attack or defense. But when our ancestors stood upright, our faces no longer sat at the ends of our bodies, and that changed their appearance and function.5 The fossils of every new version of upright savanna ape that scientists have examined have so far revealed that with the passage of time, foreheads rose to make room for rapidly growing brains; flat, fleshy noses increasingly protruded; and snoutlike jaws eventually morphed into the squarer chins and the flatter cheeks that characterize our human looks.

  We already know that our ancestors were born at progressively earlier stages in their development, and increasingly carried that high-browed, youthful look further into adulthood. The line from their foreheads to their chins steadily grew straighter. Their increasing use of tools and weapons for hunting, meat-eating, and battle reduced the need for the boulder-shaped molars used to grind leaves and nuts, and fanglike incisors used for biting both competitors within the troop, and predators outside of it. This reduced the size of their jaws, and along with their altered foreheads, moved their eyes to the center of their faces, where they sat above the broadening planes of their cheeks. All of these rearrangements transformed their expressions into better placards for displaying their thoughts and emotions.

  Over time savanna apes developed new ways to put those placards to work. Of the thousands of species of mammals on Earth, the human species owns the most expressive face. It has forty-four muscles, twenty-two on each side, about twice as many as a chimpanzee. These muscles not only adhere to bone, but also to one another and to the skin above them, enabling us to arch our eyebrows expressively or turn on a beaming smile. Our faces speak volumes of subtle emotion with just the tiniest frown, a quick wink, a pout, or a piercing, skeptical stare.6

  Face-to-Face

  Psychologists agree that we use our faces to communicate six primary emotions: happiness, sadness, fear, anger, disgust, and surprise. They disagree a bit on three others: contempt, shame, and startle. Startle, you would think, is closely connected to surprise, but some researchers feel it is unique, closer to a visceral reaction than to an emotional one. Contempt may be related to disgust, but some psychologists argue that the behaviors that elicit contempt are slightly different, and the facial movements that express it are more asymmetrical than disgust, which has its origins in avoiding dangerous food. Maybe one evolved from the other. There’s no way to know. The same is true of shame, which also may be related to disgust—in this case, disgust with ourselves. Whether these facial expressions were also used by immediate ancestors such as Homo erectus we may never know.

  Whatever the case, these reactions are so primal and deeply engrained that they are very difficult to hide and extremely tough to fake. And because of how focused our facial expressions are—because they are front and center in this little area, lighting up like neon signs—they have enormous impact. In conversation facial expressions seem to buttress what we are saying more effectively than a slouch, a rubbed neck, a turned shoulder, and other body language. When someone is surprised by something you say, you recognize the surprise in her face immediately; there is no mistaking the meaning. The same with a smile or a frown.

  The interesting thing about facial expressions is that they seem to arise without a lot of deep conscious thought, but they
are more intentional than body language. We don’t usually think, “I believe I’ll frown at that.” It simply happens, before we’ve had a chance to think. On the other hand, we can sometimes decide to consciously smile for any number of reasons—because we are happy, because we are uncomfortable, because we are covering up another feeling. In the case of speech, we almost always think about what we intend to say before we actually say it.

  In addition to the specific expressions that have evolved to symbolize clear states of mind, we use a second category, called emblems, which reveal culturally specific symbolic communications, such as a wink. Winks mean something in the United States but nothing at all on Easter Island. We also use manipulators like lip biting; illustrators (raised eyebrows); and regulators, which guide and direct conversation, actions such as nods or head turns, smiles, or a wrinkled brow.7

  Facial expressions that communicate primary emotions such as happiness and sadness might straddle the worlds of the unconscious and the premeditated. They lie in the no-man’s-land between a purely visceral, physical reaction such as a scream and the methodically conscious communication of a lawyer’s summation before a jury.

  Neurologists have found that such facial expressions as grimacing or setting our jaws trace their roots to the primal behavior of teeth-bearing. And the wide, white eyes of fear and horror, or the pursed lips of stubbornness and anger, find their origins in the evolution of mammalian midbrain nerve bundles in the cingulate gyrus facial circuit, which run along winding pathways from a brain area called the anterior cingulate cortex. They then pass directly through the hippocampus, the amygdala, and the hypothalamus—three key emotional centers in the brain—to link to the large cranial and facial nerves that control the larynx and muscles that make sound and move our lips.

  It is almost as if, still bereft of speech, evolution had found a way to step beyond the more vague language of our ancestors’ bodies to provide them with an increasingly precise vocabulary of movements focused in the one place we could never miss when dealing with one another now that we stood upright. Our faces became an emotional billboard, a miniature, more subtle, and more focused way to speak with our bodies.

  Though we can tell from the skull fragments of Homo habilis that he looked far more simian than human, his forehead was higher and his jaw smaller than the australopithecines before him. His face was probably hairless in the way his chimp cousins were. (Although it is not immediately obvious, chimps are bare-faced. It’s just that their low brows, muzzles, and smaller cheeks reduce the hairless area.) And, as Homo habilis moved across the plains of Africa, fashioning his simple, sharp tools, scavenging and gathering, competing and cooperating, this new face would have more easily expressed the increasingly complex emotions behind it.

  However, it is in Homo habilis’s evolutionary successor that we see a creature where for the first time a primate looked more like us than an ape. That was an important turning point in more ways than one.

  …

  About one and a half million years ago, an adolescent boy died making his way along the shores of Lake Turkana in what is today Kenya, Africa. We don’t know why or how; fever perhaps, possibly a predator ran him down, maybe he had somehow become separated from the troop and couldn’t find his way back. But when paleoanthropologists Alan Walker and Richard Leakey uncovered his remains in 1984, they realized they had discovered a new kind of creature. They called him Turkana Boy and named the species that he represented Homo erectus (the erect human).

  Since the discovery of Turkana Boy, other fossil finds have revealed H. erectus as the ultimate savanna primate. He was bigger, stronger, faster, and more mobile than Homo habilis, built for speed and distance—a hunter, not a scavenger, that migrated far beyond Africa.8

  From the neck down, H. erectus looked remarkably similar to modern humans, except that he was even more genetically optimized for running than we are. His rib cage was virtually identical to ours. His hips were actually more narrow and his femur and tibia, unlike the savanna apes that preceded him, proportioned exactly as ours.9 And he was tall. Leakey and Walker found an almost complete skeleton, and though Turkana Boy himself was only five feet, three inches tall, his bone structure and dimensions indicated he was an adolescent. Had he survived, Walker and Leakey estimated he would likely have grown to six feet in adulthood. When he walked or ran, his stride would have been extraordinarily graceful and efficient, an ability that would have served him well because, unlike H. habilis, he was a big-game hunter, if the fossil tools that have been discovered with other H. erectus remnants are any indications. Chief among these was the hand ax, a tool that begins to show up in the fossil record about 1.4 million years ago.

  The hand ax was a Stone Age version of the Swiss Army Knife, and considerably more sturdy and refined than the small cutting tools H. habilis used. It looked something like a large arrowhead with a pointed tip, sharp edges, and a top that could be gripped to cut, dig, club, or hammer. It took skill and strength to fashion such an ax. Mostly they were made of quartzite, lava glass, chert, or flint that had to be broken out of larger stones and then honed to an edge, probably with smaller rocks, animal bones, or antlers. Since it was often roughly the size of a hand, it was transportable, and the fossil evidence indicates that it traveled with Homo erectus wherever he went.

  And by all accounts, H. erectus went farther faster than any previous primate, probably because of his preference for meat. Our best guess is that he followed herds of herbivores that supplied him with food, clothing, and tools. While recent fossil finds indicate that H. habilis made some forays into the Middle East and southern Russia, H. erectus migrated out of Africa almost the moment he arrived on the scene, and immediately began to put thousands of miles between him and his African homelands.10 Rutgers University geochronologist Carl Swisher III and his colleagues have found H. erectus sites in Indonesia and the Republic of Georgia that date to between 1.8 million and 1.7 million years ago. After that he headed far into China and eventually over the land bridges of Southeast Asia into Australia.11

  But more than the tools, stature, and travel habits of H. erectus had evolved. In proportion to his body size, he had the largest brain of any primate, or any animal alive. It was a good two-thirds the size of ours, and some 50 percent larger than that of Homo habilis, crowding the forehead outward so the old apelike slope was nearly gone. His head and face would not have looked exactly like ours, but hints of us would have been there. The brow ridges were thicker, the mouth still a bit muzzlelike, but his would have been an expressive face. Given the environment he was living in, nature would have favored that adaptation because it made him a better communicator. Here was a creature, after all, who was not only smarter, but, arguably, more social and more interdependent than H. habilis. That would have made the communication of joy and sadness, aggression and anger, amusement and contentment, remorse and sexiness more important than ever as his inner world grew more complex and required better tools for socializing.

  The ability to charm a mate, communicate during hunting, or stare down a competitor would have been invaluable because despite his prodigious intellect, H. erectus was almost certainly incapable of speech as we know it. Standing upright had helped rearrange the shape of his throat and larynx, but generally scientists agree that the relationships among tongue, lungs, throat, and nose still needed fine-tuning before speech was possible. All efforts to teach chimps or other primates to speak words have failed miserably, not because they aren’t intelligent, but because they simply don’t have the throats, muscle control, and nerves needed for it. (There is also a difference between spoken language and simply saying words. A parrot can say words but doesn’t understand what it is saying or abide by any rules of grammar.)

  Nor had Broca’s area likely reached the level in Homo erectus it has in our species. Our brains are about 30 percent larger, and most of those additions have shown up in the cerebral and prefrontal cortex, areas key to high cognitive functions such as modern speech
. Even if the cerebral horsepower was there to think far more sophisticated thoughts than any gorilla or chimp, and even if the muscles for speech were in place, the neurons that are needed to control the intricate musculature that speaking requires may simply not have evolved yet. Alan Walker has pointed out that the inner column of H. erectus’s vertebrae was probably too small to handle the rapid and concentrated neuronal commands that wordmaking requires.12

  As evidence, Walker points to a small bone in the spine of Turkana Boy known as T7, the lowest vertebra of the thorax. All vertebrae have a hole in their centers through which the spinal cord passes. In modern humans this hole is large enough in T7 to fit all the nerve fibers needed for the fine muscle control of the rib cage and lungs when we exhale (something necessary to speech). But that same hole is smaller in Turkana Boy’s spine, even taking into account his teenage size. Walker believes that the wiring for finely controlled speech simply wasn’t capable of carrying all the signals needed to generate even rudimentary speech.13

  Nevertheless, H. erectus was, as Walker has put it, “devastatingly clever for his time,” and as his more advanced toolmaking indicates, he did have fast and facile hands. Perhaps he had other ways of communicating that didn’t require words. If the F5 region of his brain was blossoming into a primordial version of Broca’s area, and combining the power of his mirror neurons with a refined ability to manipulate objects, maybe H. erectus was able to create gestures, rather than sounds, that held meaning.

  This would have been a shattering leap forward. Given the increasing complexity of his life on all fronts—environmental, emotional, mental, and social—the forces of natural selection would have favored any improvement over facial expressions as a way to share ideas and feelings, positive or negative.14,15

  …

  British psychologist Merlin Donald has speculated that the best way for H. erectus to communicate would have been to mime what he was thinking. Fluttering fingers might have gotten across the idea of a bird or flying. Or the motion for building or using a particular tool might have become a perfectly natural way to communicate the idea of the action itself—a digging or a cutting motion, for example.