Evolution and social consequences of old age: Infant survival and elders.

Long Lives Made Humans Human, From the Paleolithic to Today.

Long Lives Made Humans Human, From the Paleolithic to Today.

Why we live so long.
Sept. 9 2013 5:45 AM

Long Lives Made Humans Human

Old people were invented in the Paleolithic Age and perfected in the 20th century.

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The history of infanticide, child labor, and child abuse—outright torture by today’s standards—shows just how cheap young lives were. Steven Pinker writes in The Better Angels of Our Nature that “From time immemorial, parents have abandoned, smothered, strangled, beaten, drowned, or poisoned many of their newborns.”

As infant and child mortality declined, so did fertility. Women didn’t need to bear “replacement children” for the ones who died, and they could be confident that a baby would live to adulthood. Survival became expected. Each child gets his or her own name right away now, and not just the recycled name of a dead older sibling.

Infanticide is a shocking crime today. And even though we allow parents to brainwash their children with fundamentalist home-schooling, when those parents choose religion over medical care, we quite rightly charge them with neglect, manslaughter, or—when it happens the second time—murder.


Today we go to heroic financial and technological efforts to save every newborn. The United States’ high infant mortality rate compared to other developed countries—about 0.6 percent of all live births, which is tragic but a lot better than the 25 to 50 percent it was in the past—is considered shameful. As Darshak Sanghavi points out, the data are complicated but mostly explained by a high rate of premature births. Neonatal medicine is one of the highest-paid medical specialties (to the point that we may sometimes be doing too much for preemies) and it has made constant improvements in the survival rate of the smallest neonates.

Children were the focus of many early public health drives—for clean milk, vaccinations, proper nutrition. Today children’s safety is the motivation for many product recalls, from cribs to window blinds to magnetic balls. Letting them roam unattended is almost as unthinkable as sending them to work in a textile factory. I don’t mean to make light of these precautions—they’re a sign that we’ve become more civilized and humane, that the world is a better and altogether different place than it was more than a century ago, and it’s all tied to our new expectation of long and healthy lives, starting at birth.

It’s the best time in the history of the world to be a child, a parent, or a grandparent.

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After the increase in child survival, the other major demographic change to come from the doubling of average human lifespan is a robust population of old people. In 1850, the proportion of people age 60 or older in the United States was about 4 percent. Today they account for about 20 percent of the population.

Economists fret about declining birth rates in the developed world and the challenge of financially supporting large elderly populations. But old people are awesome. Having a high ratio of older to younger people isn’t just a consequence of living in peace and prosperity—it’s also the foundation of a civilized society.

Things go horribly wrong in societies composed largely of young people. The Lord of the Flies is fiction, but the Lord’s Resistance Army is all too horrifyingly real. One of the worst centuries in recorded Western history is the 14th, a time of Black Death, famine, and endless war between England and France. As Barbara Tuchman points out in A Distant Mirror: The Calamitous 14th Century, one of the reasons the Hundred Years War lasted a hundred years is that repeated plagues killed off anyone, including kings and other established leaders. Again and again, teenagers or very young people inherited the throne and promptly did stupid, aggressive, frontal-lobe-deficient teenage nonsense like invading neighboring countries.

Former president of South Africa Nelson Mandela chats with Britain's Prime Minister Gordon Brown (unseen) during a meeting at his hotel in central London June 24, 2008.
Former president of South Africa Nelson Mandela in London in 2008

Photo by Dylan Martinez/Reuters

Old people aren’t merely less bellicose and impulsive than young people. They’re also, as a group, wiser, happier, and more socially adept. They handle negative information better, have stronger relationships, and find better solutions to interpersonal conflicts than younger people do. Laura Carstensen of Stanford is one of the leading researchers in this field, and she says the fact that the population is getting older is “going to change every aspect of life as we know it, including education, politics, culture, and the nature of relationships.” That’s because older people “have greater knowledge, better emotional stability, and they care deeply about making a meaningful contribution.”

“If you could take everything desirable about growing older and put it in a pill, do you know who would take it?” says Olshansky, the longevity researcher. “The young.” The magic pill would confer “a profound sense of self-confidence … a sense of peace and joy that comes from decades of a loving relationship … the sheer joy in caring for grandchildren … financial security … and thoughtful reflection and intelligence.”

If lifespan is going to continue to increase throughout the world, it may well require a positive feedback loop like the one that allowed humans to flourish 30,000 years ago. As then, more old people may lead to public health and social justice improvements that create more old people, who make the world an even better place. Something to look forward to.

Read the rest of Laura Helmuth's series on longevity.