The influential linguist Noam Chomsky advanced the idea that language may not be due to natural selection at all, and gained an important ally in Stephen Jay Gould, who admonished evolutionary biologists for jumping to the conclusion that language evolved to solve an environmental challenge. Gould believed that language might be the end result of a long ago process far removed from its present use. Steven Pinker and Paul Bloom have attempted to bridge the gap between the Chomskyites and Darwinists by proposing a middle ground. Perhaps, they posit, language developed as an offshoot of a form of mental thinking they call mentalese that in turn was in response to environmental stresses. The brain’s ability to think in these abstract terms was necessary to reconstruct a true picture of the world.12 Owen Jesperson posits that language grew out of a form of play.13
William Calvin proposed that language evolved out of our need to master complex serial maneuvers.14 As do Doreen Kimura and Philip Lieberman,15 Calvin argues that the complex serial gesture of accurately throwing a stone can be likened to the motor skill necessary to assemble sequentially a syntactically and grammatically correct sentence. Merlin Donald proposes that both language and art evolved out of a process of mimesis, a word he defines as the human ability to reconstruct three-dimensional space using spoken words or graphic images.16
Derek Bickerton set forth the theory that language was largely the result of a magnificent beneficial chance mutation, and that its primary function is to represent abstract thought internally. Only later did language serve as a communication vehicle to transfer information between individuals.17 Terence Deacon attributes the astonishing rise of language to the human ability to create symbols.18 Michael Corballis argues that the development of the spoken word arose from human gesture.19 Morton Christiansen proposes that language is a parasite that is using humans as its host, and that we have become dependent on each other to propagate. Language needs humans, and humans need language. We are in a weird kind of symbiotic relationship with a new kind of incorporeal organism called language.20
These are a sampling of the many inventive theories proposed to explain the origins of human language. But among the welter of competing claims, no one explanation has yet emerged triumphant. Something seems missing, something that could help to explain our relatively recent logarithmic leap to expressiveness.
When an adaptation as intricately filigreed as human speech bursts upon the evolutionary scene, it is usually in the wake of one or more dreadful environmental pressures bearing down, forcing a species to choose between evolving or exiting the scene. An alternative explanation: A grand new opportunity for a species makes a fortuitous abrupt appearance. To take advantage of this potential bounty, the species must hastily throw together a novel adaptation.
What, then, was the looming environmental disaster that, if not adequately and urgently addressed, would cause the human species to “go missing,” as the English are fond of saying? Alternatively, what was the manna-from-heaven opportunity that required speech?
I propose that the threat was maternal mortality, and the reward, the opportunity to be the first and only animal to roam freely in the lush uplands of the future while all the others remained individually marooned on isolated islands in the immense archipelago of the present. Suppose human language evolved so that men and women could negotiate the terms of when, where, and how they would have sex. Suppose, once they began to talk, they discovered that other creatures were at a significant disadvantage in trying to compete with them.
Psychologist Geoffrey Miller, in his recent book The Mating Mind, puts forth an intriguing theory. Miller proposes that language, instead of being prodded into existence by the exigencies of survival, was a function of sexual-selection pressures. Females chose men based on their ability to communicate effectively, and “runaway sexual selection” did the rest. Runaway selection, remember, is the evolutionary process that caused the male peacock to have such large, spectacularly gorgeous, but useless tail feathers. Females noted that any peacock that could survive with such an outlandish ensemble sported an honest handicap. Once the peahens began to select for males with ever-larger useless tail feathers, the race was on! Miller proposes that women selected men who were smooth talkers over inarticulate ones: “Language puts minds on public display, where sexual choice could see them clearly for the first time in evolutionary history.”21
His theory would predict that males would be far more facile with words than women. Yet numerous studies of gender-related speech patterns indicate a slight skewing in the opposite direction.* He explains this feature of human language by asserting that men, too, began to use language to gauge the intelligence of women. One feedback loop reinforced the other, and in a remarkably short time—Voilà!—human language achieved its present state of suppleness.†
Human language, like a fine Swiss watch, has many moving parts. All of them must be present and mesh with one another nearly simultaneously for the whole enterprise to generate intelligible sounds. The larynx (voice box) had to sink deep into the neck, far below the opening to the pharynx (throat). This descent endowed humans with the tallest larynx in all of animaldom (relative to size). Possessed of such a splendid resonant chamber, humans can articulate a wide range of vocal sounds—one of the prerequisites for nuanced messaging.
The mouth opens into the oral cavity (lips, tongue, gums, teeth, and palate), which leads to the pharynx, which becomes the esophagus (gullet), the long cylindrical tube that serves as conduit between pharynx and stomach. Food travels this gustatory highway on its way down the alimentary tract.
When the opening (glottis) to the human larynx drifted past the vestibule of the pharynx, a major design flaw became evident. The entrance leading to the delicately lined tracheal (windpipe) and bronchial (lungs) airways became exposed on a routine basis to the likes of beer and peanuts every time swallowing occurred. A trap door (epiglottis), resembling a hatch cover on the deck of a boat, evolved at the top of the larynx, so that it could slam shut the instant a warning arrived, via nerve reflexes, that food was on its way past the tongue.
Schematic of the human vocal tract.
This Rube Goldberg* arrangement was necessary in order for a human to alternate between eating and breathing through the same tube (pharynx). We are among a handful of land animals that must suspend breathing in order to eat. If one makes the mistake of inhaling at the moment of swallowing, an energetic paroxysm of coughing will ensue. The simple act of swallowing does not pose this hazard for the vast majority of other animals.
An extremely powerful incentive must have propelled us to talk to each other to justify fouling up such a vital and basic feature as the ability to breathe and eat simultaneously. That we would deviate from the standard anatomical alignment, present in virtually every other oxygen-dependent creature, points to the urgency associated with the development of human speech.*
Given the potentially fatal misalignment of pipes and tubes in their neck, it might have made more sense for Homo sapiens to heed their bizarre throat plumbing and sensibly eat in silence. But human speech is irrepressible. It is what we do best. Despite the dangers inherent in talking and eating simultaneously, people the world over consider mealtime to be the most propitious opportunity for social interaction. “Let’s do lunch” is really an invitation to shmooze; the food is secondary. Communal eating and talking over food is the sapients’ second-most-popular form of entertainment. The word com-pan-ion derives from the Latin for “to share bread.”
The number-one favorite first date between a man and a woman is a dinner for two by candlelight. Typically, he does most of the talking. Typically, she listens carefully, alert to the meta-messages of his conversation as she begins to gauge his worthiness. Typically, his primary purpose in all this folderol is to convince her to accept the advances he will likely make at her door at evening’s end.
Of course, there might be many other currents ebbing and flowing over that dark table in the corner, but this basic scenario represents the
crest of the bell-shaped curve. One can easily imagine this scene being repeated by firelight throughout innumerable Pleistocene dinner dates.
Along with the gumming up of Homo sapiens’ neck-works, there were additional prerequisite adaptations for fluent speech. A crucial one was the need to control respiration voluntarily. Breathing in and breathing out (or its equivalent) is the most fundamental exercise that fish, amphibians, reptiles, birds, and mammals do. A prolonged stoppage of breathing stills the heart, and all cellular life downstream abruptly dies. Very early on in the course of evolution, Mother Nature decided that the most efficient way to deal with something as basic as breathing was to place it under the control of the autonomic branch of the nervous system. “Autonomic” means “automatic.” One wag once characterized the autonomic nervous system as being so far from the head it doesn’t even know there is a head! Breathing occurs involuntarily with boring regularity until the day of death. Respiration is the sine qua non of life. We pronounce someone who has stopped respiring as expired.
Ponder, then, the human. While breathing remained, for the most part, under autonomic control, something remarkable occurred. Exceptionally large nerves peeled off from the spinal cord and exited the upper-thoracic vertebrae on their way to innervate the respiratory muscles. Resembling rodeo roughriders grasping the reins of bucking broncos, these robust, jumbo-sized nerves wrangled control of the muscles of respiration away from the autonomic centers. Neurons within these upper-thoracic bundles report to the highest cortical centers in the new left brain. They take their orders directly from here, rather than from the more primordial autonomic breathing centers lower down in the brain stem, the part of the brain analogous to a basement.*
A moment before the left hemisphere’s Executor decides it has something important to say, it orders an interruption of the cycle of breathing to store up air, which increases pressure in the lungs. The assembly line producing talk originates deep in the chest, at the level of the diaphragm. Broca’s area, in the left hemisphere, directs the rib and thoracic muscles, through messages carried by these specialized nerves, to release the trapped air in controlled, short spurts.† These puffs provide the raw material that will soon be tooled into sharply chiseled words farther up the line.
Next, our incredibly complicated vocal apparatus (larynx, twin vocal cords, pharynx, tongue, nose, sinuses, teeth, and lips) springs into action. As the unprocessed sausage tube of air comes hurtling out of the trachea, each of these workers on the assembly line of speech must snip, mold, sculpt, and package the exhalation streaming by into a distinct, discernible word, in milliseconds.
Paleoanatomists offer a prime piece of fossil evidence refuting those who argue for an earlier date for human speech. Compared with the generous diameters in sapients, the upper-thoracic vertebral openings for nerves exiting the spinal cord for other hominids are unimpressively stingy.24 This would seem to indicate that antecedent hominids lacked the fine motor control over respiration that human speech requires. The shape of their pharynx, larynx, and oral cavity also seems to militate against the possibility of silver-tongued orators holding forth atop a rock early in the Pleistocene Serengeti.
As wondrous as the mechanics of speech are, it staggers the imagination to contemplate how the brain reorganized itself to learn, generate, receive, and interpret the high-pitched squeakings of others. And at such an early age. Anyone who has witnessed the rapidity with which a toddler acquires speech can only marvel at the efficiency inherent in brain modules that convert babble into syntactically correct sentences between a couple of birthdays. The speed with which children acquire speech is in marked contrast to other, far less complicated motor skills, such as mastering a musical instrument, or accurately throwing a football, or building a model airplane, all of which take years of practice, diligence, and patience. Two-and-a-half-year-olds begin to master the categories of subject, verb, and object—when they haven’t yet completely mastered their bowel function.
Every day, we speak sentences that we never rehearsed. Out they come, tumbling from our mouths with little (if any) editorial interference. Where were these words just before they were spoken? What gremlin wordsmith hurriedly assembled them into a grammatically near-perfect ensemble just prior to their tripping off our tongue?
And then there is the receiver. A listener does not hear distinctly enunciated words interrupted by pauses, as if spoken words were bullets fired by a slow-action machine gun. Instead, a more-or-less continuous sound slurry issues from the speaker’s mouth. Typical conversation does not set individual words apart between empty spaces (as you see while reading this sentence).
A listener must have first learned how to establish what linguists call “auditory constancy.” Certain sounds are treated as discrete “objects,” just as a person learns to recognize things in the visual field as distinct visual objects. The smallest auditory object is a word. The phonetic sound “tree,” for example, can appear in a sentence with an immense variety of phonemes hemming it in on either side. Yet the word “tree” can be easily identified by the listener’s ear, regardless of its surrounding context.
Once each word has been identified, the listener must swiftly collate the sentence’s syntax (the linear arrangement of each individual word or phrase and the relationships among words and clauses that determine how speech is organized and interpreted). After specialized regions in the left hemisphere accomplish this feat, another part of the brain has to fish out from speech’s bouillabaisse the meaning without which a listener cannot grasp the connection of this particular sentence to the preceding or link it to the one that will follow. The brain then accomplishes something utterly magical. From mere sounds, meaning emerges. Somehow, two English-speakers accept that the uttered sound “tree” represents the tall, lush Douglas fir they both saw yesterday in a distant location. Even though the tree is no longer within view, they blithely discuss the auditory object this puff of air represents as if the actual tree stood before them. Human speech is a truly virtuoso performance!
Dramatic changes in the anatomy of Homo sapiens’ vocal apparatus, breath control, and hemispheric lateralization are the reasons that speech became possible. But the question remains: What compelled Mother Nature to slap together so rapidly so many diverse components, creating one of Her most extraordinary and singular adaptations? Most likely, there would have been a multifactorial mix of whirring feedback loops reinforcing speech, including social interactions, toolmaking, child-rearing, and hunting.
I believe that the primary impetus was sex—sex in the context of an increased awareness on the part of the female of the inherent danger of child-bearing. Speech was hurried along because men and women had to talk to each other. And the most important subject they had to negotiate was sex—with whom, when, where, under what circumstances, what must be exchanged before, and at what cost to each party.
The complex chain of events and adaptations that led to this spectacular development began around the time of the tragic death of the unheralded Unknown Mother. Given the combination of bipedalism and their fetuses’ rapidly enlarging brains, mothers began to suffer a high rate of mortality.
A factor making maternal mortality unique was that it affected only one sex. No young male ever had to confront a death threat that regularly originated from within his body. Combined with a few other deleterious factors, some isolated Homo erectus groups found their continuation endangered. Most likely, quite a few of them disappeared into extinction’s maw. One, however, survived by adapting. The key: Women acquired a rapid increase in mental endowment, enabling them to exercise control over the sexual act.
For this to come about, a critical prerequisite concerning time had to be in place. Women had to make the causal connection between two events that were separated by months—sex and signs of pregnancy. Having learned the extent and duration of the time frame of a month, some woman, somewhere, strung together a handful of months and had a momentous insight. She realized that her morning sickness
, cessation of menses, or the quickening she felt in her womb was the direct result of the transient moment of sexual pleasure she had experienced with a particular man months earlier.
Having made this backward-looking link between sex and pregnancy, she peered more months into the future and realized that she had risked her life by engaging in sex. Soon, many women grasped the sex/pregnancy/ labor-fraught-with-danger connection and its implications. Lengthier excursions into the future soberly impressed upon women the staggering output of energy required of them to raise their offspring to maturity. The ability to leap from a past event and extrapolate it into the future is the hallmark of foresight. Gyna sapiens modified her behavior. Distinct from all of her mammalian sisters, she would no longer enter into sexual relations without considerable forethought.
Meanwhile, Homo sapiens’ nervous system was undergoing a physiological change that made him interested in having sex all the time, a sharp deviation from what had been the norm.*Homo sapiens, driven by his constantly high testosterone levels, craved sex with all women, with a few exceptions, all year long. There was little to disincline his lust at the outset of the human experiment. An archaic human male found sex to be both pleasurable and entertaining, and, best of all, it initially cost him almost nothing in the long run. Only one obstacle stood in his way: He needed the cooperation of a woman.
As the sexual thermostat rose in men, it lowered in women. Men became more eager as women became more coy. An untenable situation was building that could threaten the continuation of the species. Nothing like this dissonance of desire had ever occurred before to any of the millions of other species that reproduce sexually.
Sex, Time, and Power Page 24