What Is Old Age For?

Old age is humanity's greatest invention, and on an even deeper level, it invented us. Old age transformed the way our most distant ancestors gave birth, reared their young, lived together, and fed themselves. Later it propelled the development of culture, language, and society.

Humans are primates, and among all primates we are most closely related to chimpanzees. We hold 98 percent of our genetic code in common with them. Yet a comparison of human and chimp life cycles reveals some unexpected differences.

Human beings can live twice as long as our nearest relatives—surprising in itself. Astonishing, however, is that all of this additional longevity follows the loss of fertility. Chimp and human females become fertile at nearly the same age and remain fertile for about four decades. For the aging chimpanzee, death follows hard on the heels of the loss of fertility. The human female possesses a nearly 50-year longevity bonus that follows the end of fertility. Our post-reproductive longevity exists because it affords our species a unique and powerful competitive advantage. Hidden within this extraordinary elongation of life is the story of who we are and how we came to be.

The first grandmother

One million years ago on the plains of Africa, a hominid child cries out from hunger. Her mother has recently given birth and is distracted by the needs of her helpless infant. The delivery was long and difficult and much blood was lost. The mother barely has the strength to nurse her infant. She can neither feed nor care for her older child. The mother of the new mother, the grandmother of the crying child, is moved to act. Thus was the first tentative step taken down the long road that led to the development of the modern human being. The deliberate enlistment of grandparents into the work of rearing the young stands as a defining characteristic of Homo sapiens.

Substantial advantages accrue to offspring who can be cared for by two generations of adults. The extra food and attention significantly improve survival rates. University College researchers in London found that in Gambia, infant mortality rates dropped by 50 percent if the maternal grandmother was present in the household (interestingly, no benefit was found when the paternal grandmother was in residence). Ruth Mace, one of the researchers, noted that the presence or absence of the father had no bearing on infant survival: “If the grandmother dies, you notice it; if the father does, you don't.”

Research in India has found similar results. Surely the grandmothers' contributions of time, energy, and material resources across generational lines are important, but that is not all there is to it. Humans, in particular humans living in active multigenerational families and communities, benefit from intergenerational affection.

The genius of human longevity

The development of menopause and the refinement of grandparenting played a critical role in the physical evolution of the modern human, but the story does not stop there. About 40,000 years ago, another remarkable round of adaptations changed how people lived. Homo sapiens generalized the benefits of grandparenthood by linking old age to the work of social evolution. The development of human culture—its refinement, storage, and transmission—was woven into the fabric of old age.

An African proverb says, “The death of an old person is like the loss of a library.” In these words are embedded the important role given to older adults in many African cultures. After a person has productively lived his or her life as an adult in the community, he or she is honored by initiation into the elder circle. This usually happens around the age of 65.

These elders, now masters of the school of life, have the responsibility for facilitating the transition from childhood to adulthood of new generations. They are responsible for and oversee the process of initiation. The idea of elders as “library” also reveals the fact that only the elders have full access to the tribe's knowledge base. The elders safeguard the highest secrets of the tribe and protect its medicine and inner technologies. They incarnate the wisdom of the society, which they happily share, often in the form of storytelling.

Anyone in the last half of life can attest to the difficulties, the aching joints, the fading eyesight. What is open to interpretation is the meaning of these changes. What if they are understood as a form of preparation (not unlike adolescence) for a new life as an elder of the community?

The physical decline that comes with aging actually cements the relationship between old and young. Indeed, an old man still capable of stalking, killing, and butchering a mastodon would have little inclination to spend hours doting on grandchildren, telling them stories, and instructing them in the ways of their people. An old woman still capable of producing young of her own would hardly be inclined to pour time, love, and attention into the lives of her grandchildren. The physiological changes that accompany old age, and upon which contemporary society heaps unlimited scorn, are actually essential preconditions for a socially productive old age.

Human elders have long been known as peacemakers, and for good reason. The physical changes that accompany advancing age make conflict, armed and otherwise, worthless to the old. Like statesmen serving their final terms in office, elders are freed from the tactical maneuvering that defines the struggle for adult rank and prestige. It is this freedom that allows them to put forth unique interpretations of the problems faced by their families and communities. The awareness of one's mortality that normally arises in late life—and so terrifies adults—opens new perspectives for elders on the world in which they live.