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Life Expectancy Myths

The life expectancy myth, and why many ancient humans lived long healthy lives

It is not uncommon to hear talk about how lucky we are to live in this age of scientific and medical advancement where antibiotics and vaccinations keep us living longer, while our poor ancient ancestors were lucky to live past the age of 35. Well this is not quite true. At best, it oversimplifies a complex issue, and at worst it is a blatant misrepresentation of statistics. Did ancient humans really just drop dead as they were entering their prime, or did some live long enough to see a wrinkle on their face? 

According to historical mortality levels from the Encyclopaedia of Population (2003), average life expectancy for prehistoric humans was estimated at just 20 – 35 years; in Sweden in the 1750s it was 36 years; it hit 48 years by the 1900s in the USA; and in 2007 in Japan, average life expectancy was 83 years.  It would appear that as time went on, conditions improved and so did the length of people’s lives. But it is not so simple.

What is commonly known as ‘average life expectancy’ is technically ‘life expectancy at birth’.  In other words, it is the average number of years that a newborn baby can expect to live in a given society at a given time.  But life expectancy at birth is an unhelpful statistic if the goal is to compare the health and longevity of adults.  That is because a major determinant of life expectancy at birth is the child mortality rate which, in our ancient past, was extremely high, and this skews the life expectancy rate dramatically downward.

The early years from infancy through to about 15 was perilous, due to risks posed by disease, injuries, and accidents.  But those who survived this hazardous period of life could well make it into old age.

Drawing upon archaeological records, we can indeed see evidence of this. The "Old Man of La Chapelle", for example, is the name given to the remains of a Neanderthal who lived 56,000 years ago, found buried in the limestone bedrock of a small cave near La Chapelle-aux-Saints, in France in 1908.   Scientists estimate that he had reached old age by the time he died, as bone had re-grown along the gums where he had lost several teeth, perhaps decades before. He lacked so many teeth in fact that scientists suspect he needed his food ground down before he was able to eat it. The old man's skeleton indicates that he also suffered from a number of afflictions, including arthritis.

Old Man of La Chapelle’

Facial reconstruction from the skull of ‘The Old Man of La Chapelle’. Photo source .

If we look again at the estimated maximum life expectancy for prehistoric humans, which is 35 years, we can see that this does not mean that the average person living at this time died at the age of 35. Rather, it means that for every child that died in infancy, another person might have lived to be 70.  The life expectancy statistic is, therefore, a deeply flawed way to think about the quality of life of our ancient ancestors.

So is modern society more beneficial for health and longevity than, say, the hunter-gatherer lifestyle?  To help gain an answer to this question, scientists have compared the life span of adults in contemporary hunter-gatherer tribes (excluding the infant mortality rate).  It was found that once infant mortality rates were removed, life span was calculated to between 70 and 80 years, the same rate as that found in contemporary industrialised societies. The difference is that, in the latter, most individuals survive childhood (Kanazawa, 2008).

It is certainly true that improvements in food availability, hygiene, nursing care, medical treatments, and cultural innovations have resulted in far fewer deaths caused by external injuries, infections, and epidemics, but on the other hand, we face a global cancer crisis that our ancient ancestors never had to contend with on such a scale. Are we just replacing one form of death with another?

Major causes of death

A summary of major causes of death over time. S. Horiuchi, in United NaEons, Health and Mortality: Issues of Global Concern, 1999

Archaeologists and anthropologists face a real challenge in trying to unravel reliable information about the age structure of ancient populations, largely due to the lack of a sufficient number ancient samples, as well as the difficulties in determining exact age.  Nevertheless, we can safely say that our ancient ancestors were not dropping dead at 35, and some would have even been blessed with long and healthy lives. 

Featured image: Reconstruction of a Neanderthal in the Neanderthal Museum, Mettmann, Germany.

By April Holloway

References

The life expectancy myth – by Philip J. Goscienski, M.D.

Human lifespans have not been constant for the last 2000 years – by John Hawks

Life expectancy: Myth and reality – by Mark Gorman

Life expectancy for men and women 1850 to 2000 – Mapping History

Longevity Throughout History: How has human life expectancy changed over time? – by Sharon Basaraba

Common misconceptions about science II: Life expectancy – by Satoshi Kanazawa

Comments

The thing I take from this, is that many now are trying to replicate the ancient way of eating in order to improve health, and there is a large negative voice saying that those people couldn't have been so healthy since they didn't live long. This article goes to suggest that the attempt to replicate the ancient diet, albeit in modern form, is not as ridiculous as some make out.

"Yet running beneath the surface there has been a core rate of cancer, the legacy of being multicellular creatures in an imperfect world. There is no compelling evidence that this baseline is much different now than it was in ancient times."
http://discovermagazine.com/2013/julyaug/16-history-cancer-afflicted-peo...

Life expectancy is rising even corrected for infant mortality.
if 50% of all people died at birth and the rest at 120 that gives avg age of 60.
This means to get n avg age higher more people would have live longer than 20 years just to reach 70.
So more people are living to 70+ to make the avg. with max age 120 that mean avg minimum age today is 20 or higher. The more people living above 70 the higher avg minimum age must be.

You skipped over something here, but it's a common mistake. In these discussions of life expectancy we frequently compare prehistoric people with modern people but there's another group we can compare them against: pre-industrial agricultural people. Where the life expectancy of prehistoric people was around 35, the LE of pre-industrial farmers was more like 19.

So basically modern life compensates for all the things that kill us about agriculture.

Turks and Greeks didn't regain their pre-civ, pre-agricultural average height until the 20th century. That should scare people, but most of us don't know about it.

What you write is not a revelation. It's has always been communicated in the literature since at least when I studied this 40 years ago that the average life expectancy did not mean maximum possible age. It's only through the non scientific, popular, badly researched press that such misunderstanding is perpetuated.

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