August 25, 2009

John Hawks on historical trends in length of life

John Hawks has a post on Human lifespans have not been constant for the last 2000 years, in which he criticizes the idea that there has not been a substantial change in length of life in the last 2,000 years:
Syllogistically speaking, Socrates didn't die of natural causes, therefore the Greeks had lifespans the same as ours. Or something.

...

But there's no doubt that Romans, Egyptians, and Greeks were dropping dead at age 30, 40, 50 and 60 -- at much higher age-specific mortality rates than today. Estimating the overall age profile is difficult and requires models.

Fortunately, there has been a study of the length of life in ancient Greece, that shows, that Socrates was not a unique case:
In a study of all men of renown, living in the 5th and 4th century in Greece, we identified 83 whose date of birth and death have been recorded with certainty. Their mean +/- SD and median lengths of life were found to be 71.3+/-13.4 and 70 years, respectively.

Of course, the lifespan of "men of renown" should be correlated with that of the general population, but with a higher mean, since men require time to achieve "renown". But, certainly the figure of 71 years does not seem too different from that of more recent men of renown, which is perhaps more surprising if one accounts for the high levels of violence in ancient Greece.

UPDATE I

John also writes:
More important, we don't have a clue what the maximum lifespan may have been 200, 500, or 2000 years ago. Such a tiny fraction of people make it above age 100 today that we could hardly expect to find any of them at all from skeletal samples. Nor can we expect accurate ages from historical records -- Methuseleh, anyone?

We do have some fairly secure dates for at least some ancient individuals. Strabo died at 88. Sophocles died at 90. Democritus' life span was said to be anything from 90-109. Alexis, the comic poet reached the age of 100, Isocrates, 98. So, there were probably centenarians in ancient times, although what the maximum was is anyone's guess.

UPDATE II

Psalm 90:10 gives the length of life as 70.
The days of our years are three score years and ten; and if by reason of strength they be fourscore years, yet is their strength labor and sorrow; for it is soon cut off, and we fly away.

Herodotus (1.32) has Solon give the "limit of life" at 70.
Croesus, you ask me about human affairs, and I know that the divine is entirely grudging and troublesome to us. [2] In a long span of time it is possible to see many things that you do not want to, and to suffer them, too. I set the limit of a man's life at seventy years;
This suggests to me that a length of life of 70 was formulaic in the ancient Mediterranean, and corresponds quite well with the average recorded length for prominent Greeks.

UPDATE III

Plato, in the Laws introduces a law that the guardians should rule from age 50 to at most the age of 70. Since the Laws is a work of political reform, we can assume that common Greek practice of the day (which is corroborated by historical knowledge about old-age statesmen) allowed for much older rulers, and, hence, such individuals existed in fairly substantial numbers -so that their rulership would become the object of a formal prohibition.

Aristotle, comments (in the History of Animals) that:
The reproductive function in men usually continues active till they are sixty years old; if they pass beyond this period, till they are seventy; and some men have had children at seventy years old.
In a famous passage of the Politics, after noting that male and female generation length is at most 50 and 70, he prescribes the ideal marriage age:
Women should marry when they are about eighteen years of age, and men at seven and thirty.
The prescription to marry at 37, suggests that early death must not have been too common; otherwise, it would be difficult to maintain the population's numbers, a topic which clearly occupied Aristotle, who commented on Sparta's oligandria in the same work.

UPDATE IV:

Lucian's Macrobii is dedicated to the topic of long-lived men, after listing the ages of various ancient and semi-mythical people, gives the ages at death of several historical individuals, including some fairly reliable ones:

Gorgias, 108
Of the orators, Gorgias, whom some call a sophist, lived to be one hundred and eight, and starved himself to death. They say that when he was asked the reason for his great age, sound in all his faculties, he replied that he had never accepted other peoples invitations to dinner!
Ctesibius, 104
Of the historians, Ctesibius died at the age of one hundred and four while taking a walk, according to Apollodorus in his Chronology.
Hieronymus, 104
Hieronymus, who went to war and stood much toil and many wounds, lived one hundred and four years, as Agatharchides says in the ninth book of his History of Asia; and he expresses his amazement at the man, because up to his last day he was still vigorous in his marital relations and in all his faculties, lacking none of the symptoms of health.
UPDATE V (Aug 31)

A reader writes in the comments:
The maximum life expectancy for humans seems to have been about 120years throughout recorded history.

"My Spirit will not strive with man forever, for he is indeed flesh; yet his days shall be one hundred and twenty years." Genesis 6:3

"From Cicero’s death to our day is a hundred and twenty years, one man’s life-time." Tacitus, "A Dialogue on Oratory", 17. Tacitus writes of seeing a 120 year old man in Britain in the 1st century A.D.

120 years as a length of exceptionally long-lived people is also mentioned by Herodotus:
The Icthyophagi then in their turn questioned the king concerning the term of life, and diet of his people, and were told that most of them lived to be a hundred and twenty years old, while some even went beyond that age- they ate boiled flesh, and had for their drink nothing but milk.

Of course we can't take the veracity of this story at face value, but the choice of number may suggest that it is as great as it could be without becoming unbelievable to the audience.

13 comments:

Maju said...

I'm with you: whatever the average life expectancy, the life span for the lucky ones (if getting old is any luck at all) has always been the same: it's determined by some sort of internal biological clock.

McG said...

I would suggest that lifespan is very occupationally dependent. The examples provided are all the intelligentsia of their time. It would be similar to estimating the life span of professors emeritus today. People of better means have better diets, exercise regimens (in some cases), and better health care. The real comparison is the slave/soldier of their time and ours?

Maju said...

The real comparison is the slave/soldier of their time and ours? -

There are officially no slaves anymore, anywhere. But if we're going to consider the worst off people in our global reality, then probably they have improved somewhat: they now live maybe 20 years more (what is like double lifespan).

But the slavery conditions in Imperial Rome, for example, were really brutal. For what I have read the average slave lived like 20 years.

John Hawks said...

Thanks, Dienekes --

Older lifespans were clearly well-known in antiquity. They are also well-known in Sierra Leone. The question is of the population, in particular mortality rates across young adulthood.

I don't think any testable hypothesis about maximum lifespan is possible, but the oldest attested individuals in many countries today are over 110, with the maximum at 122. We also have unverifiable claims of vastly older ages. If we accept Isocrates as an attested age, that means we've increased in maximum lifespan by 10-25 years from classical times.

Like I said, I don't think it's a fair (or testable) comparison for many reasons.

Dienekes said...

If we accept Isocrates as an attested age, that means we've increased in maximum lifespan by 10-25 years from classical times.

By definition, the oldest attested age is less than the maximum age, so we can't really conclude an increase in maximum lifespan. The latter can be much greater, but no less than the maximum attested age.

The fact that a fairly large number of individuals in the sample lived into their 90s (my list is not exhaustive, BTW, simply those that came to mind), suggests -assuming a reasonable age distribution- to me that ages in the early 100s were attained in ancient Greece.

Judith Weingarten said...

I hate to break up the party by pointing out that there were women, too, in the ancient world, some of whom lived to ripe old ages. Several Roman aged ladies are known. The prize goes to the mother (or grandmother) of Nabonidus, Neo-Babylonian king (ca 556-539 BC) left a memorial written in her 104th year:
Sin, the king of the gods, chose me and made my name famous in the world by adding many days and years of full mental capcity to the normal span of life and thus kept me alive -- for 104 happy years....

She died "a natural death" three years later, give or take a few months at age 107.

Jason Malloy said...

The fact that a fairly large number of individuals in the sample lived into their 90s (my list is not exhaustive, BTW, simply those that came to mind), suggests -assuming a reasonable age distribution- to me that ages in the early 100s were attained in ancient Greece.

But such statements only gain meaning to the extent we can compare them across time and place on a common metric. What is a “fairly large number” of people living to age 90? Are ages in the early 100s not attained in certain times and places?

I can think of multiple ways to do this, but don’t know what kind of data exists. E.g. what’s the probability in modern Europe that someone who lives until age 20 will live until age 40? 70?

Likewise what is the same probability in: 1) modern Sierra Leone, 2) Europe 1850? 3) Europe 1500? 4) Ancient Greece? Or among modern day forager populations?

Another way to conceptualize it is age-related morbidity. E.g. are people frail, demented, or cancer ridden at earlier or later ages?

Dienekes said...

But such statements only gain meaning to the extent we can compare them across time and place on a common metric. What is a “fairly large number” of people living to age 90? Are ages in the early 100s not attained in certain times and places?

Well, in the linked study, it appears that ~10 of 83 individuals reached age 90.

Jason Malloy said...

Again, such a statement only has meaning to the extent it can be compared across time and place on a common metric.

What percentage of "men of renown" live to age 90 currently. Or in 1500? Or in a hunter-gatherer tribe?

Is there a correlation between the ages of men of renown and the populations they come from? Do the ages of men of renown allow us to estimate something about the wider populations?


EXAMPLE: if 10 out of 83 MOR lived to 90, then the median age of death for adults in Ancient Greece can be estimated as 65.

Dienekes said...

What percentage of "men of renown" live to age 90 currently. Or in 1500? Or in a hunter-gatherer tribe?

Well, someone could tabulate the age at death of Charles Murray's non-Greek "geniuses", who lived about 2,000 years later than the Greeks in question. Unlike the Greek MOR, none of them were military men, so they presumably suffered violent death less frequently. I doubt they will get a much older (or younger) mean age than these Greek MOR, or a higher fraction than 10/83 of them living past 90.

Jason Malloy said...

This paper might be a start, since it includes age at death for more modern "men of renown".

The average lifespan for 524 scientists nominated for the Nobel prize between 1901-1950 (with an average birth date of 1876) was 76 years old. This was the average age men died in 2006.

Nobel prize nominees who won lived over a year longer (age 77.2) than those were nominated but did not win (75.8).

The average age of death for the MOR in the Ancient sample was about 6 years younger.

What was the average age of death for ordinary men born in 1876? Can we make a crude formula for calculating the average population lifespan from "Men of Renown"?

Ponto said...

Yes there were women back in the old days and they lived and died. But, women died quite often from multiple pregnancies and childbirth. India's population for undeveloped countries of the 1930s to 1950s shows a higher male population. Indians of the older times practiced suttee, no one wanted the older women after the husband was dead, female children were regularly killed off as being unproductive, not being able to fulfill religious obligations and contribute to family wealth. China was in the same boat.

It is not a party but a fact that women were less desired as children in many ancient societies. Educated women met fates worse than death as what happened in Egypt for one educated woman.

Hindu beliefs state that the maximum life expectancy for humans is 120 years which seems to be close to the age attained by particularly long lived people. Human and Neanderthal remains in Europe and the Middle East show these people to have died at an age less than 50 years. Even taking the widespread practice of infanticide in ancient societies, the Australian Aborigines practiced infanticide right into the European occupation of the Australian continent, life expectancy was about 45 years for whose who survived childhood. Life expectancy increases with age up to a point, at birth it is 80, at 20 years of age, it is 85.

Jack said...

The maximum life expectancy for humans seems to have been about 120years throughout recorded history.

"My Spirit will not strive with man forever, for he is indeed flesh; yet his days shall be one hundred and twenty years." Genesis 6:3

"From Cicero’s death to our day is a hundred and twenty years, one man’s life-time." Tacitus, "A Dialogue on Oratory", 17. Tacitus writes of seeing a 120 year old man in Britain in the 1st century A.D.