# How many human "generations" have their been in the last 10,000 years?March 14, 2011 9:52 AM   Subscribe

How many human "generations" have their been in the last 10,000 years?
posted by ennui.bz to Society & Culture (17 answers total) 3 users marked this as a favorite

aieee.... there not their.
posted by ennui.bz at 9:53 AM on March 14, 2011

How long is a generation?
posted by box at 9:56 AM on March 14, 2011

500. That is if you consider a generation every 20 years.
posted by JayRwv at 9:56 AM on March 14, 2011

A "generation" isn't a fixed unit of measure. There are men who have had children when they were 15, and men who have had children when they were 75. Different family lines existing simultaneously can have radically different generational periods.

Consider the Palin family. Sarah Palin's first grandchild has an uncle who is only six months older. What is the generational length in that family?

I've seen families where someone's uncle was younger than they were.
posted by Chocolate Pickle at 10:05 AM on March 14, 2011 [1 favorite]

Conventional wisdom says a generation is 20 years.
posted by amro at 10:08 AM on March 14, 2011 [1 favorite]

Wikipedia says it depends; between 16 and 27 years per generation.
posted by ErikaB at 10:11 AM on March 14, 2011

In his paper, On the Common Ancestors of All Living Humans (PDF) , Douglas L. T. Rohde has the line:
"...just over 32 generations, or 800–975 years."

Taking 900 as the number we get 10000/900*32=approx 350 generations.
posted by vacapinta at 10:18 AM on March 14, 2011

It sounds like you have a problem and you think the solution to your problem is the answer to the question you've posted. However, as other answers indicate, the answer to your question is nebulous. If you provide more information and tell us what you really want to know, i.e. why you want to calculate this, the community may be able to give you a much better answer.
posted by jeffamaphone at 10:19 AM on March 14, 2011 [2 favorites]

The question was inspired by some possibly misheard statement in a film documentary about the number of human generations since the invention of language.... which might have been 100, which seems too small...
posted by ennui.bz at 10:33 AM on March 14, 2011

My paternal grandfather was four years younger than my maternal great-grandmother (they were both in the old man's draft of WWII.) My mom's youngest aunt is three years older than her. My oldest brother is 35 and has a ten-year-old son; my youngest sister is 16. In the 100 years between 1900 and 2000, I've known families with just two generations (dad born in 1945, son born in 1990) and families with four or five (1902, 1921, 1946, 1968, 1992.)

There is no good answer here without defining "generation." 20 years is convenient, but I have ancestors in the last 150 years where the mother gave birth to her first child as early as age 14 and where she gave birth to her last child in her 40s.
posted by SMPA at 10:46 AM on March 14, 2011

Unfortunately, if I knew precisely what a "generation" is I'd be able to answer my own question. I guess I'm hoping to better understand the term but was also hoping that in the context of 10,000 years someone somewhere had come up with a number and a context for it.

I guess, ideally, I'd like to say, since the "there have been X human generations since the dawn of civilization." Of course, then i'd have to define "civilization."
posted by ennui.bz at 10:56 AM on March 14, 2011

Language doesn't mean much in a vacuum; it's always used in a specific context. So, what's the context in which you want to make this claim? Just saying you'd "like to say" something doesn't really give us the context. You can define words however you want, so you're free to define a generation as 20 years and go with that.
posted by John Cohen at 11:16 AM on March 14, 2011

Seems to me that if you simply frame your response to the question in terms of the number you choose to define a generation, anyone hearing your response will be clear on what you mean and be free to adjust their own math if they disagree with your initial conditions.
Q:How many generations have their been in the past 10k years?
A: based on the idea that a generation is 20 yrs, there have been 10k yrs/20 yrs per generation = 500 generations. adjust to suit
posted by OHenryPacey at 11:28 AM on March 14, 2011 [1 favorite]

Language developed between 50,000 - 100,000 years ago. Within genealogy, a generation is typically given a value of 25 years. 25 years x 100 = 2,500 years. Not nearly enough time.
posted by hworth at 12:29 PM on March 14, 2011

Strauss and Howe split generations by their experiences. They do interesting work but they "only" go back to the 1400's. Link and table from Wikipedia. I would say that generations in a family is not the answer.

* Arthurian Generation (1433-1460)
* Humanist Generation (1461-1482)
* Reformation Generation (1483-1511)
* Reprisal Generation (1512-1540)
* Elizabethan Generation (1541-1565)
* Parliamentary Generation (1566-1587)
* Puritan Generation (1588-1617)
* Cavalier Generation (1618-1647)
* Glorious Generation (1648-1673)
* Enlightenment Generation (1674-1700)
* Awakening Generation (1701-1723)
* Liberty Generation (1724-1741)
* Republican Generation (1742-1766)
* Compromise Generation (1767-1791)
* Transcendental Generation (1792-1821)
* Gilded Generation (1822-1842)
* Progressive Generation (1843-1859)
* Missionary Generation (1860-1882)
* Lost Generation (1883–1900)
* G.I. Generation (1901–1924)
* Silent Generation (1925–1942)
* (Baby) Boom Generation (1943–1960)
* 13th Generation (Gen X) (1961–1981)
* Millennial Generation (Gen Y) (1982–2004)
* Homeland Generation (Gen Z) (2005-?)
posted by notned at 2:04 PM on March 14, 2011 [1 favorite]

There are two ways (at least) to look at generations: a generation in a family, which might more or less correspond to something like a set number of years, and a generation in culture, which includes recent/current ones like Gen X and Gen Y. Using the latter definition, the question may be impossible to answer, but certainly you could argue for much longer generations way back in the day -- either because there was less sociocultural change or because we know so much less about it. You also run into problem with potentially having multiple generations at the same time in multiple cultures.
posted by J. Wilson at 2:45 PM on March 14, 2011

The best definition of generation, contextually, would seem to be something like "average age of parents at time of birth." So if a woman and a man had three kids at ages 19, 24, and 27 for the woman, and 21, 26 and 29 for the man, that would average to an age of 24.3.

So what would that be for all people, over all time? Here are some data that might help:
* Average age of onset of puberty generally decreases in industrial societies, particularly for women. So over all of human history, we'd expect the onset of a woman's reproductive capability to be in the late teens, generally, rather than early teens.
* Studying patterns of births and deaths in European parish churches over several centuries shows that women do not necessarily start having children as soon as they are fertile, and in particular childbearing starts at older ages in times of famine or other scarcity, at younger ages in times of plenty and growth.
* Generally, men start reproducing at older ages than women, though the degree of difference varies a great deal by society.
* Life expectancies in hunter-gatherer societies are generally significantly higher than those in farming societies, and are higher in rural rather than urban societies, until the 20th century. Discounting infant mortality, life expectancy for much of human history would not have been drastically lower than what we see today...the real anomaly was actually the 19th century, when it dipped to historic lows in industrializing cities.
* In determining generation length, what matters is children who in turn go on to reproduce. We know that survival rates are lower for children born to comparatively young and comparatively old parents.
* Women (primarily) exercising control over their reproductive potential through infanticide, abortion, and/or birth control methods has been a feature of humanity throughout recorded history. While these methods are unreliable or cruel by modern standards, they are effective at shifting reproductive patterns in aggregate. Women would have used these methods to delay onset of reproduction, to space births in order to increase resources to devote to existing children, and to cease reproduction when they already had enough children (however enough is defined.)

How does all of this add up? No idea. But I would suggest that 20 years seems rather short for a generation. 20 years would suggest that 50% (and probably more, to balance outliers) of all children who went on to reproduce were born to two teenage parents. There is no way I buy this, based on an assumption that childbearing would have started generally no earlier than the late teens, and continued into the thirties for women, and started later and continued as long or longer for men.

25 seems like a much more plausible number.
posted by psycheslamp at 4:21 PM on March 14, 2011 [2 favorites]

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