Thumbs, Toes, and Tears

by Chip Walter

  What Dunbar’s theory doesn’t directly address is the issue of mentally manipulating symbols, something that gesture and signing deal with so well. But maybe there is a middle ground where both Dunbar’s theories and theories of gesture and symbol manipulation can meet. Maybe the whines and moans and grunts of grooming are more closely related to prosody, the meanings we bring to our conversation in the tone and inflection of voices, whereas the words themselves, their meaning, syntax, and organization, are more closely related to the symbol shuffling that hands and gesture and, ultimately, Broca’s and Wernicke’s areas excel at. Both emotion and content are crucial to language as we know it; without both, any kind of communication would be crippled.

  The Insights of Dr. Wernicke

  Like Broca, Karl Wernicke, a Polish-born neurologist and psychiatrist trained in Germany, discovered the part of the brain named for him in 1874 by studying those who suffered damage to a specific cerebral area that impaired their ability to communicate. Except in Broca’s case, the impairments were related to the ability to process and understand speech (or signed language), not to generate it.

  Wernicke’s area is in the temporal lobe on the left side of the brain (in most humans), where it meets the parietal lobe, roughly behind the left ear next to the primary auditory cortex. Wernicke’s area is linked to Broca’s area. Without Wernicke’s area we would be incapable of understanding any language we hear as language. Those who suffer from Wernicke’s aphasia (or receptive aphasia) are unable to comprehend what others are saying to them.

  Brain scans indicate that Wernicke’s area plays a role in processing word sounds as speech and then searches the mind’s dictionary before passing their meanings along to other parts of the brain.

  Wernicke’s area is also often affected in those who suffer from schizophrenia and may explain why they sometimes hear hallucinatory “voices” that talk to them and that feel completely real.

  The discoveries of parts of the brain like Broca’s and Wernicke’s areas indicate that certain abilities seem to reside in extremely specific locations. For example, neurologists have found one tiny area of the brain—about 1 centimeter square—that activates only when consonants are heard! Some Wernicke aphasics are afflicted with an impairment called anomia, which makes it impossible for them to name certain objects, sometimes very particular ones—body parts or vehicles, colors or proper names, for example. One patient could not name fruits or vegetables, which prompted psychologist Edgar Zurif to joke that the syndrome should be called “banananomia.”11 But oftentimes that isn’t the case, and it seems impossible to locate any one region that owns a particular function.

  At the same time, both grooming and symbol manipulation touch directly upon two other equally crucial aspects of language: the ways we use it to create and manage our personal relationships, and the ways we converse with ourselves to shape our own mental and emotional lives—a kind of self-grooming, otherwise known as consciousness.

  These two parts of us—our social selves and our inner selves—are inextricably bound. In fact, over the course of our lives, they define and remake one another, and their fusion is what has made the cultural progress that differentiates us so thoroughly from all other creatures.

  Language is the all-purpose tool we have used to create human culture. But we could never have tethered our minds together to realize this world-building if we hadn’t first managed to cooperate and connect with one another. That’s why the emotional aspects of language are so central. In the end, nothing would get done if we couldn’t use language and the mind it has created, to adhere somehow to one another and get along.

  Connecting emotionally is so important, in fact, that most of us spend the majority of our time tuning into the apparently “impractical” aspects of communication and conversation. Fully two-thirds (on average) of the talking we do is not at all pragmatic in the sense that it accomplishes anything we might call work.12 Mostly we don’t talk about how we are going to complete this project or that, get the car fixed, or find our way from point A to point B. Instead, we jabber on about personal experiences, likes and dislikes, and the ways our relationships are going well or in circles or down the tubes. This is the grooming aspect of conversation—just touching, gossiping, checking in, and sharing.

  We know this from another experiment that Robin Dunbar and his students performed. They eavesdropped on hundreds of conversations and monitored what each person was talking about several times a minute. The practicalities of work, religion, politics, even sports usually monopolized no more than 10 percent of the conversations. The conclusion: All of this talking about others, and by implication our relationships or opinions about them, allows us to keep track of and influence others’ thinking about the friends, competitors, lovers, office workers, and family that run in our common circle, our troop. We are not simply tracking everyone else, says Dunbar, we are trying to synchronize what the troop thinks about us with what we want the troop to think about us. We are trying to match our self-image with our social image.

  Think of conversations among teenagers. They act as complex feedback loops that each teen uses to project an inner image to the rest of the group in the hope that that image will be accepted. If it is, then that acceptance in turn reinforces the teen’s inner image. Each party jockeys for position, advertising the traits that make him or her an important member of the group, which is to say datable, influential, worth listening to. Teens might use charm, humor, sex appeal, kindness, creativity, even bullying to accomplish the goal, but the work is unrelenting and always evident. They are learning to be both individuals and social animals at the same time. As we grow older, the methods may become more subtle and refined, but they never stop.13

  The whole issue of successfully managing our reputations is important in all company, but it is particularly important when members of the opposite sex are around. Another Dunbar study reveals that when a group is all male, the discussion of ethics, business, and religion consumes no more than 5 percent of the conversation. But when women and men are both involved, it rises to 15 to 20 percent. Dunbar calls this “vocal lekking.” Lekking is a behavior in the animal kingdom that males of the species use to show off what they have to offer potential mates. Dunbar found that younger men in a group spend two-thirds of their time talking about themselves. In other words, they are strutting their stuff—verbally.

  Apparently this works. Anthropologists have found that tribal chiefs are often both gifted orators and highly polygenous, which means they excel at attracting and keeping multiple mates, a practice that very effectively spreads that chief’s particular genes into the next generation.14

  Women, as a group, however, talk considerably less about themselves than men. But this isn’t necessarily a sign of weakness or deference. They may be keeping their mouths shut so they can sit back and evaluate what the males in the conversation have to offer, the way peahens decide which peacocks they want to mate with by comparing tail feathers.

  These sorts of social minglings, loaded with their constant monitoring, jockeying, imagining, and lekking, could only have accelerated the social complexity versus brain arms race. After all, it is hard cerebral work trying to imagine what a potential mate might find most attractive in you while at the same time keeping an eye on the competition so you can outmatch them. Nothing is more changeable, even chaotic, on a day-to-day basis than the shifting tides of personal relationships. And nothing is more important. It requires constant use of the prefrontal cortex, the continual construction and redesign of strategies, plans, and scenarios, not to mention the rationalizations we routinely use to explain to ourselves why we, or others, do the things we do.

  Communication, in the form of a budding language, would have been the primary tool in managing those relationships, and evolution would have favored early humans who used their masterful communication skills to better handle them. Applying language to the organization of the hunt or to explaining how to whack an ax head would certainly h
ave been useful, but in the big scheme of things it wouldn’t hold a candle to the advantages that a silver tongue delivered when telling a riveting story about how the mammoth was felled. Eloquence contributes to how others come to form their image of us, and that image is central to our personal, emotional, and social lives. They are all connected because the persona that emerges out of the groupthink of the troop is crucial not only to how others see us but also to how we see ourselves.

  This interpersonal feedback loop means that we understand problems more easily when they are connected to social situations; we have the inborn capability to unravel social problems because our brains evolved to deal with them.15 Linda Cosmides, a scientist at the University of California, Santa Barbara, has even argued that humans have a special ability to recognize instances when social contracts are being violated, or when actions do not sync with words. This is crucial because members of groups will disintegrate if trust erodes, and soon instead of safety in numbers, chaos reigns and devolves into every man for himself.16,17

  Another way of putting this is to say that our personal behavior is enforced not just from the outside, but from the inside, too. If we fail the troop, we risk becoming isolated, and no one wants to be isolated, companionless, and powerless. So we try very hard to get along with others.

  This is one of the great ironies of human nature. We are self-aware enough that we want to express our individuality, but dependent enough on those around us that we also want, sometimes desperately, to fit in. In many ways our lifelong goal is to somehow strike a reasonable balance between the two. In this way the language we use to glue us together also shapes what we tell ourselves is acceptable behavior. This is what John Skoyles and Dorion Sagan call “the troop within our heads” in their book Up from Dragons.

  …

  We have, thanks again to our prefrontal cortex, an ability that psychologists call Theory of Mind (ToM), a talent for guessing at what we think others may be thinking. It is absolutely central to imagining how others may react to what we do. Whether we want to please or deceive them, correctly guessing what is on others’ minds improves the chances of us getting what we want.

  When Theory of Mind and the troop inside of our head combine, something like a moral sense emerges. If, for example, taking all of the bananas was going to feed one of our ancestors in the short term, but make him a social outcast in the long term, then he may have decided not to take them, or at least have decided to share some of them. Or if sharing all of the bananas was going to make him powerful, he may have decided to be generous rather than selfish. Either way, in imagining what others may think is acceptable behavior and also in your own long-term best interest, you will very likely curb your more selfish desires. There is a kind of justice in that.

  Anyone who is particularly good at this kind of thinking is going to have an evolutionary advantage and an advantage in life. It’s the classic, “I know that he knows that I know he really wants the chocolate ice cream, not the vanilla.” It harkens back to game theory and mirror neurons, the ability to put yourself into someone else’s shoes. This is the prefrontal cortex laboring overtime. It is also the troop hard at work inside your head, and once it is there (and we all have it, starting with the earliest lessons we learn at the feet of our parents), it is there to stay, shaping the people we are.18

  All of these forces—social, mental, and emotional—with which we endeavor to control the behavior of the person we call our “self” really constitute the thing we call consciousness. Human self-awareness and conscious, purposeful behavior really can’t be separated. But it’s not altogether clear how the more ancient, unconscious drives that we carry with us from our ancestral past influence how we act or why we act that way.

  Cognitive scientist Michael Gazzaniga has a theory about this. He believes it can all be traced very directly to the place in our brain where speech is being processed.

  …

  For some reason, in most humans, both the generation and comprehension of language is handled on the left side of the brain. There are various theories as to why. Some believe it may be related to handedness.19 The left hemisphere of the brain governs control of the right side of the body, including our right hands. Most humans are right-handed. There is some evidence that beneath the skulls of Homo habilis there was just the slightest bulge of an incipient Broca’s area. Since Broca’s area is involved in controlling the hands as well as in generating speech, maybe there is some connection between right-handedness and speech, some specialization that was going on. After all, this part of the brain already housed the computational circuitry necessary for using hands to arrange objects. Maybe it was a natural location for the deliberate, sequential control of symbols and words as well.

  In The Language Instinct Steven Pinker theorizes that language may have taken up residence in the left side of the brain because it wasn’t very concerned with dimensions such as space and direction. “Human language may have been concentrated in one hemisphere,” he says, “because it … is coordinated in time but not environmental space: words are strung together in order but do not have to be aimed in various directions.”20

  In his book on the origins of language, psychologist Michael Corballis argues that at some point there may have been a single-gene mutation that created a strong bias toward both right-handedness and left-cerebral dominance for language. In short, it was an evolutionary accident, and in another universe, had certain genes mutated differently, we would be mostly left-handed and right-headed.

  It is also possible that the right hemisphere was simply crammed to capacity when we first began to develop the neuronal bricks and mortar for language, so the gray matter had to find room in the left hemisphere. The right hemisphere already had long been busy perceiving emotional cues as well as all nonverbal but very powerful forms of communication, such as shapes and facial expressions. Experiments have even shown that a mother carrying her baby tends to detect the soundless grimace of her child if she is holding the baby on her left side, which is controlled by the right hemisphere. This may explain why most mothers tend to hold their babies in their left arm. Even monkeys and apes respond more intensely and more quickly when the facial signals of other monkeys are more visible to the left sides of their faces.21

  Whatever the reasons why speech and verbal thought are generated in the brain’s left hemisphere, Michael Gazzaniga feels it is central to the nature of our species. Over the years his work has focused on the two hemispheres of the brain, and he has conducted exhaustive tests with “split-brain” patients, individuals who have had the thick bundle of 250 million nerves called the corpus collosum that connect the two hemispheres of the brain surgically severed. This is usually a last-resort treatment for rare cases of epilepsy where the seizures make normal life impossible.

  For most people their hemispheres work just fine after the operation, and the brain seems to mysteriously find other ways to move information between them. But under certain experimental conditions it becomes clear that in split-brain patients the two sides of the brain are not in direct communication in the way most of us experience. Visual information, for example, is not communicated from the right to the left or vice versa. The same with smell, touch, and sound. Since hemispheric control of the body is also largely contralateral (the right hemisphere controls the left side of the body, and the right brain the left of the body), it turns out that patients can only manipulate objects with their right hands if the commands come from the left hemisphere, and vice versa. (Either hemisphere can control the muscles of both upper arms, however.)

  Over the years Gazzaniga has worked closely with a particular patient named Joe, whose corpus callosum was severed after he began having terrible seizures at age nineteen. Joe hasn’t suffered any problems as a result of the surgery, and like most split-brain patients has gone on to live a normal and seizure-free life. However, because of the operation the two hemispheres of Joe’s brain are not in instant communication. This isn’t usually noticeab
le, except under specific conditions that have revealed some remarkable insights into how our minds work.

  In one experiment with Joe that I witnessed several years ago, he was seated in front of a computer screen. Gazzaniga asked him to stare directly at a dot in the middle of the monitor. As Joe did, an image of a tree was flashed on the right side of the screen, and on the left the word BLOW. They appeared simultaneously, but for only a split second. Fixating on the dot in the middle ensured that Joe’s left eye only saw the word BLOW and his right eye only registered the image of the tree. That meant that the image captured by Joe’s right eye was sent to the verbal, left side of his brain, and the word BLOW was sent to the mute, right side.

  After the experiment Joe was asked what he saw, and he immediately answered a tree because the left, speaking side of his brain had registered the image. But when he was asked what he saw on the left side of the screen, he said he had missed it. The fact is that he hadn’t missed it. His eye registered the word and sent it to the right side of his brain, but it couldn’t put what he saw into words because it had no capacity for language.

  In another experiment Joe was asked to close his eyes. Gazzaniga then put a roll of tape in his left hand. He held it and rolled it around in his palm several times, but when he was asked what he thought it was, his best guess was a pencil—really nothing more than a stab in the dark. But when the same roll of tape was placed in his right hand, the left side of his brain immediately enabled him to identify it accurately.

  These experiments mainly proved that Joe’s two hemispheres weren’t in direct and instantaneous communication. But the next experiment illustrated the powerful ways that the speech centers in the brain paint a picture of the world that each of us recognizes as reality, and how that picture may also play a crucial role in generating a sense of self.22 Joe sat in front of the same computer monitor. This time the word ORANGE was flashed on the left side of the screen, where the signal traveled to the right, nonverbal hemisphere of the brain, and the image of a bird was flashed to the right. Next Joe was asked to draw a picture of what he saw with his left hand (the one controlled by the nonverbal side of the brain). Joe promptly picked up an orange marker and drew not the word ORANGE but a picture of an orange. When he had finished, however, he was perplexed. He really had no idea why he had drawn such a thing. When asked what he saw, he explained he saw a bird, not an orange (that was what registered in the left, speaking part of his brain). Gazzaniga then asked him to finish drawing what he saw with his right hand. Joe then converted the orange he had drawn into a bird that looked something like a kiwi.