Unbound: How Eight Technologies Made Us Human and Brought Our World to the Brink

by Richard L. Currier

Our species is unique among all earthly creatures in its ability to comprehend and plan for the long term. Yet we are still motivated by ancient animal instincts, including the drive to expand and multiply to the limits of the possible. Other living things are limited in their ability to reproduce by the relatively fixed nature of their relationship to the environment. But by allowing us to escape the bonds of our biological destiny, technology has made it possible for us to continue multiplying, even as we have moved the world ever closer to an uncertain and potentially disastrous future.

Five million years ago, the adoption of fabricated spears and digging sticks by our ape-like ancestors encouraged us to stand, walk, and run upright. This innovation eventually produced a radical restructuring of mammalian anatomy that freed the forelimbs from the duties of locomotion. With the free use of their powerful forelimbs and dexterous hands, our ancestors were able to control fire, fashion clothing, and build dwellings. These technologies liberated us from the need to live in the tropical environments where we originated and allowed us to populate the vast temperate regions of Europe and Asia.

One hundred thousand years ago or more, when we began to use verbal and visual symbols to communicate, we freed ourselves from the limitations of direct personal experience. We gained the ability to share information over space and time, enabling us to pool our knowledge with others and develop cultures that were passe...

Ten thousand years ago, the technology of agriculture liberated us from the constant search for food that preoccupies every other animal species. In the process, we were no longer bound to the endless wandering that had always been our fate as hunters and gatherers. We began to grow our own food, live in villages, and accumulate both ...

Five thousand years ago, we developed powerful new technologies of transportation and communication. These included large seagoing ships, wagons pulled by beasts of burden, and forms of writing that enabled us to record information for posterity and to communicate with others over vast distances. These technologies of interaction enabled us to build cities, create civilizations, and evolve increasingly sophisticated forms of art, science, comm...

Five hundred years ago, the precision instruments of clocks, sextants, compasses, microscopes, and telescopes freed us from the limitations of our unaided sensory organs. And scarcely more than two hundred years ago, the technology of reciprocating engines liberated us from our ancient dependence on the physical power of the human body and our beasts of burden. As a result, we have conquered the world with the powers of science and the machinery of industry, and...

An eighth metamorphosis is now under way, triggered by the key technology of digital information, which has made it possible for all human beings to visit and communicate with each other, anywhere on Earth. This has enabled us to create a global culture and society that transcends national boundaries. The challenge for humanity will be to embrace this global civilization without sacrificing either the individual liberties or th...

But in this book I have used the word “technology” as it has been defined by anthropologists and primatologists, who encountered preindustrial technologies in the ancient societies of hunters and gatherers and in the primeval societies of wild chimpanzees. Thus, anthropologists have defined technology—in its widest and most inclusive sense—as the deliberate modification of any natural object or substance with forethought to achieve a specific end or serve a specific purpose. Anthropologists have always regarded the tools, weapons, garments, and dwellings of hunting and gathering societies as true technologies.

Each of the eight key technologies described in this book is actually a complex collection of things and processes. What ties each of them together as a single entity is the common purpose for which each was created and used.

I have used the traditional term “hominid” throughout this book as the preferred term for all prehistoric and modern bipedal species in the human family tree.

A metamorphosis, however, describes a sweeping change in every aspect of culture and society: diet, habitat, social relationships, economic behavior, group size, technology, evolutionary pressures, and even human anatomy itself. There have been thousands of revolutions in the course of humanity’s evolution and history, but there have been only a few genuine metamorphoses.

For the first time in human history, it has become possible for anyone on Earth to interact with almost anyone else on Earth, quickly and affordably. Human society will be transformed as much by this latest metamorphosis as it was by the seven key technologies of the past and the seven metamorphoses they unleashed.

Most of this book explores the technology-driven changes that gradually transformed us into much more than just another animal species. But in order to make sense out of the strange complexities of human society and culture, we have to begin by understanding the primate baseline—the anatomy and behavior of monkeys and apes. These were the genetic starting points, the natural raw materials, out of which the unique anatomy and behavior of human beings evolved. By understanding the nature of these evolutionary building blocks, we can more fully appreciate how far we have come—and how far we have yet to go.

While on the surface it may seem odd to describe hierarchical behaviors such as dominance and submission as a type of bonding, the fact is that these hierarchical relationships tend to be exceedingly stable and long-lasting. Social hierarchies are common among group-living animal species because they minimize hostilities among the members of the group as well as provide a mechanism that allows the entire group to take concerted action when necessary.

Just as monkeys and apes compete for dominance and social rank within their particular hierarchies, we humans also compete for dominance and social rank within our own hierarchies of art, science, technology, business, government, fashion, entertainment, and sports. But while the players change, the play remains the same: a stable social hierarchy in which each individual has a particular rank, in which life-or-death battles are infrequent, and in which winners and losers know their status, and stay in their places, but nevertheless remain watchful for opportunities to move up in the hierarchies to which they belong.

Upon reaching puberty, the adolescent primate typically leaves its mother’s group and actively seeks out friendships and sexual relationships with members of another group—and ultimately to gain acceptance as a permanent member. This is called exogamy—meaning “marriage outside of the group”—and among most primate species it is the males who leave to join another group, a phenomenon known as male exogamy.

The physical similarities between humans and other primates are obvious, while the behavioral similarities are not always as apparent. Group solidarity and the concept of a homeland; the social bonds forged by motherhood, sex, friendship, and social hierarchies; the flexibility of the fission-fusion society; the advantages of exogamy; and the rudiments of hunting, warfare, tools, weapons, customs, and traditions all exist among non-human primates. These are the genetic building blocks of human behavior. Without them, human society would have never evolved, and the world we live in would have never come into being.

The ability to carry and wield a spear long enough to attack and kill another animal from beyond the range of its biological weaponry would have had powerful survival value. Once the ancestors of the hominids had adopted the technology of the spear, those individuals who could stand firmly on their hind limbs—while jabbing and thrusting a spear with their forelimbs—would have had a clear advantage over their competitors. The longer these individuals could remain standing, the farther they could walk and run on two legs, and the larger and heavier weapons they could carry with them, the more effectively they could defend their mates and offspring against attacks from would-be predators—and the more meat they could bring back to share with the other members of the group. For all of these reasons, the survival value of fabricated spears would have been sufficient to bring about the major anatomical changes required for a four-footed animal to evolve into a two-footed animal.

Hominids are the only animal species in which the males are predators, the females are foragers, and both sexes regularly share the different foods they obtain.

But in recent years, evidence has been accumulating that indicates fire was used by Homo erectus at least as early as 1.5 million years ago,

With their new-found ability to control fire, the emerging humans were freed from the necessity of sleeping in the trees at night. For the first time, the hominids became fully terrestrial beings.

When the emerging humans began to use fire to ward off predators after sunset, they created an artificial source of light that had the effect of suppressing the production of melatonin and delaying the onset of sleep. As a result, the adoption of fire freed the hominids from the ancient limitations of the twelve-hour tropical day and extended their normal waking hours well into the night. This is the point in human evolution when our ancestors began staying up late—extending the time of wakefulness well beyond the average period of daylight that governs the circadian rhythms of all other tropical animals. Staying up late gave the emerging humans unique new advantages. It provided additional time for eating, for making things, and for social life and communication. The human predilection to eat after the hours of darkness, to work on weaving, tool-making, and other tasks by the firelight, and to gossip, relate the events of the day, and recite folk tales and myths, represented unique behaviors that no other species could duplicate. All of these behaviors were made possible when the emerging humans first began building fires at night and staying up late, while lesser creatures slept or kept their distance.

The human brain weighs about three pounds—about 2 percent of the average adult’s total body weight. Yet when it is active, the human brain can consume as much as 20 percent of the body’s available energy—roughly ten times as much energy, pound for pound, as is consumed by the human body as a whole.

We humans, the descendants of 55 million years of tree-dwelling ancestors, who lived and died in the open air of the forest, are no longer able to live out in the open. Instead, we crave “a roof over our heads” in the form of a secure canopy that not only protects us from the wind, rain, and snow but also forms a closed, cave-like environment that traps the heat from our fires and protects us from attack by predators.

But the Stone Age was not a distinct period or age at all, since it includes the entire evolutionary history of the hominids, from their earliest appearance several million years ago to the fully modern humans of today’s world. This immense period of time encompasses many of the technologies described in this book, including the domestication of fire, the invention of clothing and dwellings, the development of symbolism, the adoption of agriculture, and the beginnings of urban civilization. In fact, the Stone Age technically began to end only when the techniques of metallurgy were first developed a few thousand years ago. Considering that the earliest stone tools date from approximately three million years ago, the Stone Age would thus comprise about 99.8 percent of all human history—and all the remaining “ages” together would amount to only one-fifth of 1 percent of the hominids’ time on Earth.

This may be another case in which absence of evidence is incorrectly interpreted as evidence of absence.

Thus, as the tremendous expansion in the size of the hominid brain took place during the past million years, it created increasing difficulties in childbirth for the emerging humans, and this problem became even more acute as the emerging humans evolved into modern humans with truly massive brains. If the birth canal remained fixed in size while the infant’s head and the brain within it was growing progressively larger, how did the evolving hominids continue giving birth to babies with increasingly larger heads? The evolutionary solution to this problem turned out to be that as the size of the brain increased, hominid babies began to be born before their brains were fully developed. In fact, if you apply the normal rules of mammalian fetal development to humans, the “normal” gestation period for humans would be at least twelve months, not nine. But at twelve months the average infant brain would simply be too large to pass through the average human birth canal, making human birth mechanically impossible.

Anyone who has ever seen the birth of a cat, dog, pig, cow, or horse knows that other female mammals give birth to their babies in a matter of minutes. But giving birth to a human infant is the longest, most difficult, and most dangerous process of giving birth among any mammalian species. In fact, before the adoption of modern medical techniques at the beginning of the twentieth century, roughly one out of every hundred human births resulted in the death of the mother.

Symbolic communication freed us to invent the complex cultures and powerful ethnic identities with which every human being came to identify and owe allegiance.

It is important to note that while the capacity for learning and creating symbols resides in the DNA of anatomically modern humans, the form and meaning of the symbols invented by modern humans is entirely cultural and has no basis in biology. All of the meanings that are contained in symbolic communications, whether visual or auditory, must be learned in childhood, remembered in adulthood, and passed down through the generations as the shared cultural knowledge of the social group.

The Manias further proposed that this reconstructed elephant bone with twenty-eight marks was the symbolic expression of a lunar calendar, in which each mark represented a single day in the twenty-eight-day lunar cycle. If this is correct, the first seven marks would have represented the seven-day period from the new moon to the waxing half-moon, the next fourteen marks the fourteen-day period from the waxing half-moon through the full moon to the waning half-moon, and the final seven marks the period from the waning half-moon to the following new moon.

Nevertheless, traces of red ochre—a naturally occurring pigment used by many hunting and gathering people in the course of ritual observances—have been found in many Neandertal grave sites, some as old as two hundred thousand years. This indicates that, at the very least, these prehistoric people regarded death as an important milestone in human life, and that the death of a member of the group was observed by rituals in which the use of symbolic substances such as red pigment played a significant role.

Begin at the beginning,’ said the King to the White Rabbit, ‘and go on till you come to the end: then stop.’”14 This deceptively simple formula describes a powerful form of communication of which no other species is capable. While the emerging humans may have had a primitive form of language, and the Neandertals almost certainly were capable of spoken language, the profound changes in human life ushered in by the anatomically modern humans may have been due to their unique ability to tell a story in narrative form.

The essential mechanism of biological evolution consists of three basic processes. First, each generation inherits the characteristics of its parents through information that is encoded in the genetic material contributed by both mother and father. Second, some of this information is inevitably lost or changed through a largely random process we call “mutation.” Third, most mutations have either no effect on the development of the organism or are harmful or maladaptive, making life more difficult for the individuals whose DNA has been altered. Nevertheless, a very small number of random mutations turn out to be beneficial and help the individual organism adapt more efficiently to its environment. As a result, the more beneficial mutations become increasingly common in a breeding population and—if they are sufficiently adaptive—eventually become the new normal within the breeding population. This is the basic process that produced the ability to walk and run on two legs, use fire, cook food, construct dwellings, fashion clothing, and so on.

When the human social group, which for millions of years had consisted of no more than a few dozen individuals, freed itself from its primate inheritance and expanded into tribes of thousands, a process of fusion began that has culminated in the formation of vast nation-states consisting of millions of individuals and claiming dominion over the earth’s entire land surface. Whether our species is capable of a final act of fusion—in which all living people achieve a shared identity as members of a single global culture and civilization—is a question that will determine the future not only of our own species but also of most forms of life on Earth. This is, in fact, the question that lies at the heart of this book.

With the waning of the ice ages and the warming of the earth, humanity was about to embark on its next great metamorphosis. Each of the four metamorphoses that had already taken place had transformed the biology of our ancestors in significant ways. The technology of spears and digging sticks transformed us from quadrupedal into bipedal animals. The technology of fire and cooking resulted in the loss of our body hair, a massive expansion in the size of our brains, and the disappearance of our tree-climbing anatomy. The technology of clothing and shelter enabled us to migrate out of the tropics and made it possible for our “premature” newborns to survive in cold climates. And the technology of symbolic communication involved significant changes in our brains, freeing us from the slow pace of biological evolution and enabling us to take advantage of the speed and flexibility of cultural evolution.

But when the Paleolithic era came to an end with the waning of the last major ice age, humanity freed itself of the need—which limits and circumscribes the lives of all other animals—to be perpetually engaged in the search for something to eat. When the technology of agriculture made it possible for humanity to produce its own food and store it for the future, our species cast off a burden that it had borne, along with all other animals, since its beginning. Unbound from the daily search for food, our ancestors settled down in permanent settlements composed of hundreds and even thousands of people, learned to specialize in arts and crafts, and began to multiply. New and powerful technologies of transportation and communication enabled us to build cities and multiply still more, creating enormous civilizations composed of hundreds of thousands of people. The technology of precision machinery made it possible for us to create modern industrial nation-states composed of millions, and as a result we have multiplied so fast that our long-term future is now at risk. And the recent development of digital technology—which enables us to trade, visit, and communicate with all members of the human species—has made it possible, for the first time in our history, for humanity to fuse into a single global society. None of these metamorphoses in society would have ever taken place had humans continued to pursue the hunting and gathering existence with which our species began.

Was the technology of symbolic communication the critical element that had been missing from human cultures during more ancient periods of human prehistory? Was “the appearance of language and symbolic systems,” combined with the warming of the earth, the essential combination of factors that enabled humanity to finally begin producing its own food?

Thus, as soon as people began to live in one place, the pursuit of material wealth assumed an importance that it had never had before. And the increasing importance of wealth and status can be clearly seen in the evidence that has survived in the Fertile Crescent from Neolithic times, when the Natufians adopted the practice of harvesting and storing their wild grain in granaries.

Evidence from many preindustrial societies shows that, once a society begins to live in one place—even if it continues to live by hunting and gathering and has not developed an agricultural way of life—it begins to pursue the accumulation of material wealth in ways that are remarkably similar to the traditions of agricultural people.

agricultural societies tended to cultivate strong and often exclusive bonds between parents and children. They strove to instill in their children a sense of duty toward their parents, and, with few exceptions, they placed a high value on marital fidelity—especially on the part of women—to ensure that the paternity of a man’s child was never in doubt. In this way, the value of children to their parents in agricultural societies led over time to a culture of fierce possessiveness toward children and to severe restrictions on the sexual freedom of women. In fact, these cultural traits became so deeply ingrained in the cultures of our agricultural ancestors that both of them have persisted into the modern age.

In time, the societies of these regions began to invent and adopt new technologies of interaction—the sailing ships, wheeled vehicles, domesticated horses, and systems of writing that made it possible for people and communities to interact over time and space. As a result, the market towns, religious centers, and communities of wealthy and powerful families gradually grew into urban centers that began to dominate the smaller and less powerful neighboring towns. Eventually, as the technologies of interaction grew in sophistication and effectiveness, these expanding urban centers knitted the settlements of entire regions into a network of allied communities, and in time these communities became the seeds of the urban civilizations that sprouted, one by one, in the cradles of civilization scattered across the globe.

In time, the steady accumulation of wealth, military power, and religious authority by communities that were located in strategic and well-defended locations led to the development of a small number of powerful, fortified urban centers. These settlements, considerably larger than any that had ever previously existed, came to exercise commercial, military, and religious authority over extensive rural populations, and the “city-state” was born. These were the first human societies in which people could be complete strangers to each other and yet could live and work side by side without hostility or distrust.

Over the course of the past five thousand years, thousands of city-states and hundreds of empires have come and gone, but the hallmarks of urban civilization have remained essentially the same until the emergence of industrial society two hundred years ago. A large but powerless agricultural population lived in the countryside and produced the food consumed by society as a whole. At the same time, a small but powerful ruling class—including an extensive bureaucracy, an exclusive priesthood, and an organized military force—lived inside the confines of an urban center that was protected by massive fortifications and filled with monuments, palaces, and temples.

Wherever urban civilizations arose, full-fledged systems of writing were developed because they were needed. Societies composed of tens or hundreds of thousands of individuals—most of whom are strangers to each other—require technologies of communication that can transmit complex messages effectively and reliably over time and space. When these urban societies did not already possess a system of writing—or were unable to borrow a system of writing from their neighbors—they invented their own.

After 1000 BC, when archers mounted on horseback and armed with the composite bow became commonplace in ancient armies, the chariot and its spear-throwing or longbow-wielding occupants were gradually retired from battle.

It has been estimated that roughly 85 percent of the population of all civilized societies throughout history consisted of agricultural food producers, while the remaining 15 percent consisted of the urban professionals who made civilized society possible. And every ancient city found it necessary to control the movement of goods and people between the countryside and the city, to ensure that there would always be a large and reliable supply of food for the city dwellers—and that the people of the countryside could rely on the cities for the products, services, and military protection upon which they depended.

In 1992 the evolutionary anthropologist Robin Dunbar studied the relationship between brain size and group size in numerous primate species. He found that the species with the largest brains were able to maintain the largest cohesive social groups while those with the smallest brains were able to maintain only the smallest cohesive social groups. His mathematical model predicted that, given the size of the human brain, human groups would retain their cohesiveness up to approximately the size of only 150 individuals. The number 150, which came to be called “Dunbar’s number,” turns out to be approximately the maximum number of full-fledged relationships a normal human being can maintain at any given time.

The transformation of human society into urban civilizations, however, involved a great fusion of people and societies into groups so large that there was no possibility of having personal relationships with more than a tiny fraction of them. Yet the human capacity for tribal solidarity meant that there was literally no upper limit on the size that a human group could attain. And if we mark the year 3000 BC as the approximate time when all the elements of urban civilization came together to trigger this new transformation, it has taken only five thousand years for all of humanity to be swallowed up by the immense nation-states that have now taken possession of every square inch of the inhabited world.

Precision machining made it possible to manufacture a wide variety of machines that humans had never created before: steam engines, printing presses, long-range weaponry, electric generators, telegraph wires, telescopes, microscopes—the list goes on—and the synergies created in the resulting expansion of information, science, industry, and military power gave birth to a new kind of society, based not on the limited energy of humans and animals but on the seemingly unlimited energy of fossil fuels. And it all began in the Middle Ages with the invention of the mechanical clock.