1.3 What Makes Humans So Different from Other Animals? The Six Steps to Humanness
Human beings clearly differ from other animals. From humanity’s earliest origin (about 6–8 mya, when an apelike primate began walking on two feet) to the period beginning about 10,000 years ago (when modern climates and environments emerged after what is commonly known as the Ice Age), six key attributes developed that make us unique: bipedalism, nonhoning chewing, complex material culture and tool use, hunting, speech, and dependence on domesticated foods (Figure 1.4, pp. 14–15). The first development represents the most profound physical difference between humans and other animals: namely, the manner in which we get around. We are committed to bipedalism; that is, walking on two feet. The next development was the loss of a large, honing canine tooth, like the one that apes typically use to shred their food (mostly plants), replaced by the simple nonhoning canine, with which we process food in ways unique to humans. Some authorities argue that our ancestors’ honing canine disappeared due to a changed diet. The changes involving canine reduction and loss of honing function in early hominins occurred around 5.5 mya (see chapter 10).
FIGURE 1.5First Tools The earliest stone tools date to 2.6 mya and are associated with early human ancestors in East Africa. The example shown here is from the Gona River area in the Afar region of Ethiopia. This tool likely had various functions, including the processing of plants and meat for food.
Today, our species completely depends on culture—and especially material culture—for its day-to-day living and its very survival. Culture is a complex human characteristic that facilitates our survival by enabling us to adapt to different settings. Material culture is the part of culture that is expressed as material objects that humans use to manipulate environments. For example, hammers and nails are forms of material culture that enable us to make cabinets, tables, and countless other forms of material culture. The material remains of past cultures go back hundreds of thousands of years, to the first simple tools made from rocks. The best evidence for the date of these tools is 2.6 mya from East Africa (see also chapter 10; Figure 1.5). Material culture today makes our lifestyles possible. Can you imagine your life without it? We could survive without modern additions to material culture, such as cars, computers, television sets, plumbing, and electricity, as our ancestors did before the past century. But what about living without basic material culture, such as houses and clothing, especially in climates where it can be very, very cold in the winter? Without material culture, how would any of us get food? The answer to both questions is simple: we could not make it without some forms of technology—to regulate temperature, to acquire food, and so on. Some societies are much less technologically complex than others, but no society functions without any technology.
Anthropologists and animal behaviorists have shown that human beings are not, however, the only type of animal that has or can employ material culture. Primatologists have observed some chimpanzee societies in Africa, for example, making simple tools from twigs (Figure 1.6). In laboratories, chimpanzees have been taught to use physical symbols that approximate human communication. Still, these and other forms of material culture used by nonhuman species are nowhere near as complex as those created by humans.
The other three key attributes of humanness—hunting, speech, and dependence on domesticated foods—appeared much later in human evolution than bipedalism, nonhoning chewing, and complex material culture and tool use. Hunting here refers to the social behavior whereby a group of individuals, adult males in general, organize themselves to pursue animals for food. This behavior likely dates back to a million or more years ago. Some nonhuman primates—such as chimpanzees—organize to pursue prey, but they do not use tools or travel long distances as humans distinctively do when they hunt.
1.4
The Six Big Events of Human Evolution
BIPEDALISM, NONHONING CHEWING, DEPENDENCE ON MATERIAL CULTURE, SPEECH, HUNTING, AND DOMESTICATION OF PLANTS AND ANIMALS
BIPEDALISM 6 MYA
The upright, bipedal (two-footed) gait was the first hallmark feature of our hominin ancestors.
Human Foot
Chimpanzee Foot
NONHONING CHEWING 5.5 MYA
Humans’ nonhoning chewing complex (below) lacks large, projecting canines in the upper jaw and a diastema, or gap, between the lower canine and the third premolar.
The chewing complex of apes such as gorillas (below) has large, projecting upper canines and a diastema in the lower jaw to accommodate them.
Human Male Skull
Gorilla Skull
MATERIAL CULTURE AND TOOLS 2.6 MYA
Humans’ production and use of stone tools is one example of complex material culture. The tools of our closest living relatives, the chimpanzees, do not approach the complexity and diversity of modern and ancestral humans’ tools
SPEECH 2.5 MYA
In the entire animal kingdom, only humans can speak and, through speech, express complex thoughts and ideas. The shape of the hyoid bone is unique to hominins and reflects their ability to speak. Speech is part of the overall package in the human lineage of increased cognition, intelligence, and brain-size expansion.
HUNTING 1 MYA
Humans’ relatively large brains require lots of energy to develop and function. Animal protein is an ideal source of that energy, and humans obtained it for most of their evolution by eating animals they hunted. To increase their chances of success in hunting, humans employed tools they made and cooperative strategies.
DOMESTICATED FOODS 11,000 YEARS AGO
In recent evolution—within the last 10,000 years or so—humans domesticated a wide variety of plants and animals, controlling their life cycles and using them for food and other products, such as clothing and shelter.
FIGURE 1.6Toolmaking Once thought to be a uniquely human phenomenon, toolmaking has been observed in chimpanzees, the closest biological relatives of humans. As seen here, a chimpanzee has modified a twig to scoop termites from nests. Other chimpanzees have used two rocks as a hammer and anvil to crack open nuts. More recently, gorillas were seen using a stick to test the depth of a pool of water they wanted to cross. Tool use such as this likely preceded the first identified tools (see Figure 1.5).
An equally distinctive human behavior is speech. We are the only animal that communicates by talking. Unfortunately for research purposes, recording-and-listening technology was invented only about a century ago. For information about long-past speech, anthropologists rely on indirect evidence within the skeleton. For example, the hyoid bone (located in the neck) is part of the vocal structure that helps produce words. The unique appearance of the human hyoid helps anthropologists conjecture about the origins of speech in earlier human ancestors.
The most recently developed unique human behavior is the domesticated manner in which we acquire our food. About 10,000–11,000 years before the present (yBP), humans began to raise animals and grow plants. This development led to our current total reliance on domesticated plants and animals for food. This reliance has had a profound impact on human biology and behavior, and it represents a fundamental part of our biological evolution and influences our health and living conditions.
Human beings’ unique behaviors and survival mechanisms, and the anatomical features related to them, arose through the complex interaction of biology and culture. Indeed, our ancestors’ increasing dependence on culture for survival has made us entirely culture-dependent for survival. The behaviors that are unique to humans—speech, tool use, and dependence on culture—are also related to the fact that humans are very smart. Our remarkable intelligence is reflected in our abilities to think and interact in the ways we do (and usually take for granted), to communicate in complex ways, and to accomplish diverse tasks on a daily basis in order to survive. Our brains are bigger and have more complex analytical skills than the brains of both other primates and animals in general. These biological attributes enable us to figure out complex problems, including how to survive in a wide range of environments and rapidly changing circumstances.
The American anthropologist Robert Boyd and his colleagues argue that while humans are the smartest animals, in no way are we individually smart enough to acquire all the complex information necessary to survive in any particular environment. Today and through much of human evolution, our species has survived owing to our complex culture, including tool use and other technology, practices, and beliefs. For hundreds of thousands of years, humans have had a record of unique ways of learning from other humans. Retaining new knowledge, we pass this information to our offspring and other members of our societies, and this process extends over many generations (Figure 1.7). That is, social learning makes it possible for humans to accumulate an amazing amount of information over very long time periods. Anthropologists are finding that social learning is also present in nonhuman primates and other animals. However, the degree of knowledge transmission is more developed in humans, a process that is highly consequential for our education.
FIGURE 1.7Social Learning A father teaches his son traditional wood-carving in Ubud, Bali, Indonesia. Social learning provides a means of accumulating and maintaining knowledge over many generations.
In the chapters that follow, you will be looking at these processes and behaviors—the particulars of biological anthropology—from a biocultural perspective. It is the unique and phenomenal interplay between biology, culture, and behavior that makes us human.
