What are the Characteristics We All Share?
What were the universal qualities shared by our early ancestors as they migrated out of Africa? Just as the physical human evolution developed over time, so too did the evolution of human universals: those qualities and characteristics that are commonly shared by all human beings in the world today.
Human beings have many physical, behavioral, and mental characteristics that set us apart from other animals. One physical characteristic, standing up, was crucial in human evolution because, among other benefits, it led to increased population. Somewhat later came tool use, an increasingly large brain, and self-awareness.
These physical changes resulted in countless behavioral changes, among them the development of a cooperative society including farming and industries small and large. The physical developments in turn prompted vast changes in human society so that cultures and behavior changed rapidly over a very short time.
We present the distinctly human characteristics here in the rough order in which they evolved. But it is better to think of the process of human adaptation as the simultaneous development of all these characteristics, in a positive feedback loop. The effects of the loop have continuously increased the difference between our nearest ancestors and us. TOP
Bipedalism: Standing Up and Walking
Human beings are bipedal—that is, we walk on two feet instead of on all fours. Chimps and gorillas can stand upright at times, but when they move they typically do so on all fours. A fossil skeleton called Lucy, our first ancestor found whose bones show that she walked on two legs, dates from about 3.75 million years ago, about 1 million years before the use of tools. Bipedal walking and running are efficient modes of locomotion. People can cover greater distances over time than any other animal. Walking enabled our ancestors to travel into unexplored territory, which in turn led them into new and often dangerous situations. Almost all other animals live their lives in the environment in which they are born. The view from two feet off the ground is more limited than the view from four to five feet. To four-legged animals smell is important. A standing animal can see farther than it can smell. Since standing animals can spot approaching danger as well as opportunities farther away, a more sophisticated visual system developed along with upright posture. Hands were freed from weight-bearing responsibilities, making tool use possible. Erect posture also led to profound changes in human sexuality and social systems. Although we cannot be sure, this complex of factors surrounding bipedalism was probably our first adaptive advantage. TOP
Immaturity and its consequences
With the freeing of the front limbs, the hind limbs had to adapt to bearing the entire weight of the body. The human back was not originally “designed” to support upright posture (which partially explains why back pains are a common complaint). To support the additional weight, the human pelvis grew thicker than that of the great apes. As a result, the thickened pelvis made the female’s birth canal, the opening through which infants are born, much smaller. While the birth canal was becoming smaller, however, the fetus’s brain and head were growing larger. If there had been no evolutionary correction for this new disadvantage, the human species would have eventually died out because of inefficient childbirth. The evolutionary solution was to have human babies born very early in their development. At birth a chimp’s brain is about 45 percent of its adult weight, while a human baby’s brain is 25 percent of its adult weight. Human children have the longest infancy in the animal kingdom; they are not as competent and independent as baby chimps or baboons. Within a day, baby baboons can hold onto their mothers by themselves. The human child is helpless and will die if not taken care of for years.
The major portion of the brain’s development occurs outside the womb, exposed to and influenced by many different environments, events, and people. The environment plays a much greater role in the development of the human brain than in any other animal’s brain development. And because the environment is different for each person, the specific abilities each of us develops differ considerably. TOP
The Mother-Father-Infant Relationship
A helpless infant requires at least one caretaking parent to survive. In other species, a newborn can fend for itself within a relatively short time, and the mother can almost immediately resume her place in the group, providing her young with food and protection. But taking care of a human infant is a full-time job. For most of human history, taking care of the infant has been the mother’s job. In subsistence societies, like hunter-gatherers, parents working together as a team were better able to get enough food than a nursing mother alone. The father can hunt for meat and bring it home to the mother, who stays close to home gathering fruits and vegetables. Human fathers take an active role in feeding their young. TOP
Dexterity and Tool Use
Once the early humans walked, and the forelimbs were freed from their weight-bearing function, the limbs developed into hands with great dexterity, capable of more precise movements such as those needed for fashioning and using specialized tools.
Human ancestors began to make tools as early as 3 million years ago. Specialized tools for chopping, digging, killing, cooking, washing, and skinning led to specialized labor by those who used them. Some people gathered wood or nuts, others dug for roots, still others hunted and killed animals. Axes made the hunt more efficient; choppers and scrapers could be used to butcher a large animal at the kill. At home, tools helped scrape the nutritious marrow out of the bones; animal hides could be scraped to make warm clothing.
One mark of improved dexterity is the modification in the tools themselves. Those made by Homo erectus about 1 million years ago took 35 blows to make. The knives of Cro-Magnon, made about 20,000 years ago, were more delicately fashioned, requiring at least 250 separate blows. About 5000 BCE, human beings began to extract and use metals. This advanced technology created the need for more specialized labor. Specialization led inevitably to greater interdependence among individuals. TOP
Pivotal to human adaptation is our large brain, which has evolved faster than any other human organ. It took hundreds of millions of years to create the 400 cc. brain of Australopithecus, yet in only a few million years the brain had grown to 1250-1500 cc. and had developed the capacity for abstract thought: the key to the human adaptation. It has helped us to adapt to every kind of geography and climate. It enables us still today to transcend our biological inheritance. The brain underlies mental life: to learn, to create, to invent, to think and say things no one has ever thought. The brain increased in size radically from Ramapithecus to Homo sapiens. It is the largest, relative to body size, of all land mammals, but the size of the brain is not what matters.
What is crucial is where the brain expanded. Although the anatomy of much of our brain is identical with that of other primates, our cerebral cortex, the uppermost part of the brain, is the largest and most elaborate of all primates. The cortex is the area of the brain devoted to learning, organizing, planning, and other mental activities.
All primates have developed varying degrees of fine-motor control. The main mode of locomotion of nonhuman primates is swinging through trees, which requires the ability to grasp tightly onto branches. To do this, an animal must have extremely well-developed motor control in the fine muscles of his limbs.
A kind of “grammar” is necessary to know how to get from one place to another, which hand to use, and where and how tightly to grasp. Those areas of the brain that control fine-motor movements, and which became further developed in toolmaking, are the same ones involved in language. The increasing size of the cerebral cortex thus gave our ancestors great advantages—from control of delicate muscle movements to the development of speech and written language. TOP
A necessary part of human culture is language, a form of symbolic communication of external action and internal thought that has a structure of sound, gesture, meaning and logic similar to all other languages. It contains a classification system and allows humans to speak and think in abstractions. Thus we can plan for the future or make conjectures about something or someone not present. The subtleties of language include manipulation of others, lying, humor, gossip, insults, metaphor, and poetry. Click for more on language. TOP
Personhood: Self Consciousness
Another important feature is personhood, which includes a responsible self as distinguished from others that understands intentionality and the difference between right and wrong. Conflict is familiar to the groups, who have customary ways of handling it and are aware of what belongs to them and what belongs to others. They are moved by sexual attraction and at times disturbed by sexual jealousy. They know that other people have an inner life just as they do and feel emotional pain and other kinds of emotions in the same way. TOP
Humans are not solitary beings but live most of our lives in groups or connected to groups of which immediate family and other kin are the most important. We have a social structure with leaders, laws, politics, division of labor, etiquette, song, dance, decorative art, rituals, taboos, myths, and religious beliefs.
Human beings all over the world share the same basic emotions, they are: sadness, anger, disgust, fear, surprise and happiness. What accounts for different ways that emotions appear are different cultural display rules, such as whether one can cry in public or show surprise or disgust in different situations.
We all see a spectrum of colors. Most animals don’t see colors at all. Yet, color vision isn’t strictly limited to human beings, as the great apes also have it, although it isn’t clear if it is as good as ours.
While the great apes can do rudimentary counting, human beings obviously have a common number sense. In primitive societies it is limited to the concept of “1, 2 ... and many”; but all human beings can learn to do mathematics, although it is difficult for some. Complex counting in primitive societies is often done by matching, for instance using stones to represent the number of domestic animals in a group at the beginning of a day and then checking the number of animals against the stones in the evening.