Tag Archives: sex

Father’s Day

906 – 858 thousand years ago

One man draws out the wire, another straights it, a third cuts it, a fourth points it, a fifth grinds it at the top for receiving the head; to make the head requires two or three distinct operations; to put it on, is a peculiar business, to whiten the pins is another; it is even a trade by itself to put them into the paper; and the important business of making a pin is, in this manner, divided into about eighteen distinct operations, which, in some manufactories, are all performed by distinct hands.

Adam Smith famously observed the enormous advantage to be gained from a division of labor in the manufacture of pins. But in one form, the division of labor is far older than Smith’s pin factory: virtually every human society has a division of labor by sex. Here’s a chart from anthropologist George Murdock on the sexual division of labor across cultures.


M Exclusively male
N Predominantly male
E Equal/equivalent for both sexes
G Predominantly female
F Exclusively female
Index is weighted average, male vs.female

The sexual division of labor is an unusual arrangement among animals: not just males and females cooperating in provisioning offspring (birds do it, wolves do it), but doing very different jobs.

It seems very likely that by today’s date on Logarithmic History, Homo erectus had a sexual division of labor, in particular a male specialization in hunting large animals. But there is a problem in figuring out how this arrangement could have gotten started. Smith listed “a tolerable administration of justice” as one ingredient in economic progress: his pin factory would have run into problems without property rights to keep people from swiping pins. In the context of the sexual division of labor, a similar problem arises if we assume that hunting is a form of “paternal provisioning.” How could this ever get off the ground, given an initial condition of promiscuity or alpha-male polygynous mating? (If we assume that monogamy is already in place, the problem is less serious. When paternal provisioning occurs in other mammalian species, it apparently evolves out of a prior condition of scattered monogamous pairs. However this sequence seems improbable for human ancestors.)

Maybe the assumption about hunting as paternal provisioning is wrong. Maybe hunting is about showing off, not providing for a family. (Hemingway is showing off; his family isn’t going to eat the lion.)

hemingway lion

But a recent article considers another possibility: a “Dad” who provisions his family may succeed in a world of “Cads” if there are strong complementarities in economic activities between males and females, i.e. a sexual division of labor. In this respect, human dads may really be something special.

What do women want?

1.27-1.21 million years ago

As we noted in the last post, human females conceal ovulation (no chimp-style monthly sexual swellings) but advertise nubility (with conspicuous fat deposits). Presumably this has to do with sexual selection, via male mate choice. But sexual selection may have operated in the opposite direction, on male anatomy, as well.

Males of most primate species have a baculum, or penis bone. Human beings and spider monkeys are the exceptions. (A mnemonic: the mammals with penis bones are PRICCs – primates, rodents, insectivores, carnivores, chiropterans=bats.) The baculum helps to retract the penis when it’s not in use, so males in our species, lacking a penis bone, have more conspicuous dangling organs than most primate males.

This information comes from a recent book The Evolution of Beauty: How Darwin’s Forgotten Theory of Mate Choice Shapes the Animal World – and Us, by Robert Prum. Prum also cites a paper arguing that Adam’s “rib” (Hebrew tsela), the thing God used to make Eve (Genesis 2:21-23), was actually his baculum, providing a creationist explanation of “congenital human baculum deficiency.” The book contains lots of interesting tidbits like this, although I don’t know that I buy its central argument, that sexual selection via mate choice is largely a result of non-adaptive aesthetic preferences.

Men’s penises lack something else found in most primate species: most male primates have keratinized spines on their penises. But a gene involved in the development of penis spines got turned off in our evolutionary lineage, some time after our split with chimps, but before our split with Neanderthals. We’re not sure why. Penis spines might be favored in promiscuously mating species if they help one male dredge out sperm left by earlier matings with other males. So (relative) monogamy in our lineage might remove the evolutionary advantage of spines. But a non-spiny penis might also be less sensitive, and make for more prolonged intercourse.

If all this doesn’t answer the question “What do women want?”, it at least narrows down the possibilities a bit: not men with bony, spiny penises, apparently.

Calories and curves

1.34-1.28 million years ago


This figure is from a neat recent paper comparing energy expenditure (TEE or Total Energy Expended) and fat among humans and our closest relations: chimpanzees (genus Pan), gorillas (Gorilla), and orangutans (Pongo). (The numbers are adjusted for differences in overall body mass.)

What stands out here is that humans are a high energy species. Also we carry a lot more body fat than the other great apes. This applies particularly to women, who need a lot of extra fat to meet the high energy demands of human infants. But it even applies to men. For both sexes, a high energy life style means you want to carry around an extra reserve of fat in case of emergencies.

We don’t know how long ago our ancestors decided to crank up their energy consumption. Maybe back with the rise of Homo erectus (just a few days ago on Logarithmic History). Or maybe later, when the typical modern human pattern of slow maturation was more firmly in place. At some point in the near future, we’ll actually nail down the specific genetic changes leading humans to accumulate more fat, and be able to put a date on the change. It may be that the distinctively human mating system also arose back then, with human females concealing ovulation (no chimp-style monthly sexual swellings) but advertising nubility (with conspicuous fat deposits appearing at puberty).

A high energy life-style also goes with extensive food sharing and changes in human kinship. (Here’s me, on beating Hamilton’s rule through socially enforced nepotism.)

Bikers and hippies and apes

We’ll have more to say about the evolution of our very distinctive social organization as the blog carries on. But it may be informative to consider our closest relatives, chimpanzees and bonobos. The two species are closely related, having diverged only about 2 million years ago. They remain physically quite similar, and people didn’t even figure out that bonobos are a separate species until the twentieth century. There are some broad similarities in their social organization. Both species have fission-fusion societies, in which subgroups form and reform within a larger, more stable community. Both species have male philopatry: males spend their lives in the community they were born in, while females transfer out of their natal community to a new community when they reach sexual maturity. In both species, females commonly mate with many males over the course of an estrus cycle. But there are some important differences.

Jane Goodall began studying chimpanzees in the wild at Gombe National Park, Tanzania, in the 1960s. The early reports from Gombe captivated the world with stories of chimpanzee social life, tool use, and interactions with human observers. It was the 1960s, and chimpanzees – hairy, sexually promiscuous, grooving in the jungle ­– looked familiar: they were hippies.

The picture darkened a lot in the 1970s, when the community at Gombe split in two. Between 1974 and 1978, the two daughter communities were effectively in a state of war. Males from the larger of the two communities carried out a series of raids against the smaller, with raiding parties opportunistically picking off and killing isolated individuals, eventually eliminating all the males and some of the females. Subsequent studies of other chimpanzee populations have made it clear that this was not an isolated incident: intergroup warfare and group extinction are general features of chimpanzee life. Chimpanzees are still hairy, still sexually promiscuous, but they now look less like hippies and more like bikers. Really scary bikers.

Bonobos look like the real hippies. They are more peaceable. They show less violence between groups, with members of neighboring groups sometimes even feeding peacefully in proximity to one another, something unthinkable for chimps. There is also less within-community male-male violence among bonobos. Bonobo females play a major role in regulating and intervening in male-male competition, and may even be dominant to males. There are tensions within bonobo communities but these are often resolved by (non-reproductive) sexual activity. For example, females, who are generally not related to one another because they were born elsewhere, might be expected to find themselves fighting over food. Instead they settle potential feeding conflicts peaceably by “g-g (genital-genital) rubbing,” rubbing their sexual swellings together until they reach orgasm. Or do a pretty convincing job of faking it: “I’ll have what she’s having.”

However recent DNA tests have revealed an unexpected twist to the chimpanzee/bonobo comparison. In spite of the more peaceable nature of male bonobos compared to male chimps, it turns out that there is actually greater reproductive inequality among male bonobos and a stronger relationship between dominance rank and reproductive success! Dominant male bonobos are more successful than dominant male chimps in monopolizing reproduction. If bonobos still look like hippies, then they are the kind of hippies where a lot of free loving is going on, but the whole happening is run by and for the leader (backed up by his mom) and his groupies.

When you were a tadpole and I was a fish

1.24-1.18 billion years ago

And here’s a post (with a poem) that works for Valentine’s Day, tomorrow.

The Boring Billion rolls on. The atmosphere is one percent oxygen or so thanks to photosynthetic bacteria and algae. The ocean still largely anoxic and thick with sulfates and sulfate-eating bacteria. Eukaryotes have been around for a while, and are diversified, although still all single celled (as far as we know).

Sexual reproduction begins with eukaryotes, and by now some groups are presumably differentiated into male and female. And so here’s a poem for Valentine’s Day, by the biologist Langdon Smith. Martin Gardner has a nice account of the poem, in his book “When you were a tadpole and I was a fish,” and here’s a great video of the poem spoken by Jean Shepherd.

By Langdon Smith (1858-1908)

When you were a tadpole and I was a fish
In the Paleozoic time,
And side by side on the ebbing tide
We sprawled through the ooze and slime,
Or skittered with many a caudal flip
Through the depths of the Cambrian fen,
My heart was rife with the joy of life,
For I loved you even then.

Mindless we lived and mindless we loved
And mindless at last we died;
And deep in the rift of the Caradoc drift
We slumbered side by side.
The world turned on in the lathe of time,
The hot lands heaved amain,
Till we caught our breath from the womb of death
And crept into life again.

We were amphibians, scaled and tailed,
And drab as a dead man’s hand;
We coiled at ease ‘neath the dripping trees
Or trailed through the mud and sand.
Croaking and blind, with our three-clawed feet
Writing a language dumb,
With never a spark in the empty dark
To hint at a life to come.

Yet happy we lived and happy we loved,
And happy we died once more;
Our forms were rolled in the clinging mold
Of a Neocomian shore.
The eons came and the eons fled
And the sleep that wrapped us fast
Was riven away in a newer day
And the night of death was passed.

Then light and swift through the jungle trees
We swung in our airy flights,
Or breathed in the balms of the fronded palms
In the hush of the moonless nights;
And oh! what beautiful years were there
When our hearts clung each to each;
When life was filled and our senses thrilled
In the first faint dawn of speech.

Thus life by life and love by love
We passed through the cycles strange,
And breath by breath and death by death
We followed the chain of change.
Till there came a time in the law of life
When over the nursing sod
The shadows broke and the soul awoke
In a strange, dim dream of God.

I was thewed like an Auroch bull
And tusked like the great cave bear;
And you, my sweet, from head to feet
Were gowned in your glorious hair.
Deep in the gloom of a fireless cave,
When the night fell o’er the plain
And the moon hung red o’er the river bed
We mumbled the bones of the slain.

I flaked a flint to a cutting edge
And shaped it with brutish craft;
I broke a shank from the woodland lank
And fitted it, head and haft;
Then I hid me close to the reedy tarn,
Where the mammoth came to drink;
Through the brawn and bone I drove the stone
And slew him upon the brink.

Loud I howled through the moonlit wastes,
Loud answered our kith and kin;
From west to east to the crimson feast
The clan came tramping in.
O’er joint and gristle and padded hoof
We fought and clawed and tore,
And cheek by jowl with many a growl
We talked the marvel o’er.

I carved that fight on a reindeer bone
With rude and hairy hand;
I pictured his fall on the cavern wall
That men might understand.
For we lived by blood and the right of might
Ere human laws were drawn,
And the age of sin did not begin
Til our brutal tush was gone.

And that was a million years ago
In a time that no man knows;
Yet here tonight in the mellow light
We sit at Delmonico’s.
Your eyes are deep as the Devon springs,
Your hair is dark as jet,
Your years are few, your life is new,
Your soul untried, and yet –

Our trail is on the Kimmeridge clay
And the scarp of the Purbeck flags;
We have left our bones in the Bagshot stones
And deep in the Coralline crags;
Our love is old, our lives are old,
And death shall come amain;
Should it come today, what man may say
We shall not live again?

God wrought our souls from the Tremadoc beds
And furnish’d them wings to fly;
He sowed our spawn in the world’s dim dawn,
And I know that it shall not die,
Though cities have sprung above the graves
Where the crook-bone men made war
And the ox-wain creaks o’er the buried caves
Where the mummied mammoths are.

Then as we linger at luncheon here
O’er many a dainty dish,
Let us drink anew to the time when you
Were a tadpole and I was a fish.

“My nights were sour, spent with Schopenhauer”

February 1997 – March 1999

In December 1998, Bill Clinton is impeached by the House of Representatives, only the second US President to be impeached, after Andrew Johnson in 1868. The charges are perjury and obstruction of justice. Clinton has a long record of philandering going back to his days as governor of Arkansas and continuing to the White House. His attempts to cover this up give Republicans in the House an opening for impeachment. Clinton also pays a $90,000 fine for lying about his relations with Paula Jones, an Arkansan who accused him of sexual harassment. He eventually settles out of court with Jones for $850,000.

In 2000, the Presidential campaign of Al Gore keeps its distance from Clinton. In polls, an exceptionally high percentage of potential voters list “moral character” as an important issue in the election, and these voters mostly favor Gore’s opponent, George W. Bush. Gore believes that the Clinton scandals cost him the election.

Here’s a quote from the great pessimistic philosopher Schopenhauer (my translation):

Sexual love … next to the love of life … shows itself as the strongest and most active of motives, and constantly lays claim to half the powers and thoughts of the younger portion of mankind. It is the ultimate goal of almost all human effort. It exerts an unfavorable influence on the most important affairs, interrupts every hour the most serious occupations, and sometimes confuses for a while even the greatest minds. It does not hesitate to intrude with its trash, interfering with the negotiations of statesmen and the investigations of the learned … It devises daily the most entangled and the worst actions, destroys the most valuable relationships, breaks the strongest bonds, demands the sacrifice sometimes of life or health, sometimes of wealth, rank and happiness. Indeed, it destroys the conscience of the otherwise honest, makes traitors of the once loyal … One is forced to cry: Why all this noise? Why the strain, turmoil worry and effort? … Why should such a trifle pay so important a part, and constantly introduce disturbance and confusion into the well-regulated life of man? But to the earnest investigator the spirit of truth gradually reveals the answer: it is no trifle that is in question here; on the contrary, the importance of the matter is quite proportionate to the seriousness and ardor of the effort. The ultimate aim of all love affairs … is actually more important than all other aims in human life, and is therefore quite worthy of the profound seriousness with which everyone pursues it. What is decided by it is nothing less than the composition of the next generation … This is the key to the problem.

Schopenhauer actually anticipated a lot of Darwin’s theory of sexual selection – for example, how differences in men’s and women’s sexuality derive from differences in potential rates of reproduction. However he got there with the help of a lot of high-flown Germanic idealist talk about the Will to Live, rather than with scientific arguments.

Schopenhauer’s greatest disciple is Richard Wagner. If most of Mozart’s operas are about the triumph of monogamy in the face of obstacles, then most of Wagner’s operas are about the destructive antisocial nature of sexual love.

The veil

January 1981 – January 1984


From Persepolis: The Story of a Childhood by Marjane Satrapi.

Before the Iranian Revolution, a number of Western scholars wrote books attempting to develop general theories of revolution. Barrington Moore’s Social Origins of Dictatorship and Democracy is an early classic in the genre, treating different political trajectories – liberal, reactionary, and communist – as the outcome of different bargains between landowners, peasants, and bourgeoisie. Theda Skocpol’s States and Social Revolutions covers some of the same ground with an added focus on states and war-making.

But the class-centered theories that these authors develop don’t do a very good job of accounting for the Iranian Revolution or broader political currents in the Islamic world. It’s difficult to map Middle Eastern political movements onto a Left-Right spectrum. And both democracy and communism made far less headway in the Middle East than in either Latin America or East Asia. Nor do the class-based theories have much to say about gender relations and patriarchy, major issues in Islamic politics.

One of our themes in the past few months of Logarithmic History has been how the major civilizations of Eurasia have found different ways of combining patrilineal clans, state formation, and major world religions. From this perspective, the Islamic world is distinctive in several respects. The custom of marriage within the patrilineage (stemming from a culture of honor long predating Islam in the Near East, but spread far and wide by Muslim conquests) probably contributes to making the Muslim Middle East exceptionally fragmentary and fissiparous. And Islam has been exceptionally successful in overriding alternative identities based on nationality and class. Today for example, according to surveys, most Pakistani Muslims think of themselves as Muslims first and Pakistanis second, while most Indian Hindus think of themselves as Indians first and Hindus second. Michael Cook’s Ancient Religions, Modern Politics makes the case for Muslim exceptionalism in some detail in comparing the Islamic world with Hindu India and Catholic Latin America.

Sexual intercourse began in 1963

October 1962-October 1966

Sexual intercourse began
In nineteen sixty-three
(which was rather late for me) –
Between the end of the Chatterley ban
And the Beatles’ first LP.

Up to then there’d only been
A sort of bargaining,
A wrangle for the ring,
A shame that started at sixteen
And spread to everything.

Then all at once the quarrel sank:
Everyone felt the same,
And every life became
A brilliant breaking of the bank,
A quite unlosable game.

So life was never better than
In nineteen sixty-three
(Though just too late for me) –
Between the end of the Chatterley ban
And the Beatles’ first LP.

Annus Mirabilis, by Phillip Larkin

Weighing in with different opinion, here’s Michel Houellebecq, for whom the sexual revolution maybe came too early – in his mother’s generation – rather than too late.

It’s a fact, I mused to myself, that in societies like ours sex truly represents a second system of differentiation, completely independent of money; and as a system of differentiation, it functions just as mercilessly. The effects of these two systems are, furthermore, strictly equivalent. Just like unrestrained economic liberalism, and for similar reasons, sexual liberalism produces phenomena of absolute pauperization. Some men make love every day; others five or six times in their life, or never. Some make love with dozens of women; others with none. It’s what’s known as ‘the law of the market’. In an economic system where unfair dismissal is prohibited, every person more or less manages to find their place. In a sexual system where adultery is prohibited, every person more or less manages to find their bed mate. In a totally liberal economic system certain people accumulate considerable fortunes; others stagnate in unemployment and misery. In a totally liberal sexual system certain people have a varied and exciting erotic life; others are reduced to masturbation and solitude. Economic liberalism is an extension of the domain of the struggle, its extension to all ages and all classes of society. Sexual liberalism is likewise an extension of the domain of the struggle, its extension to all ages and classes of society. … Certain people win on both levels; others lose on both. Businesses fight over certain young professionals; women fight over certain young men; men fight over certain young women; the trouble and strife are considerable.

Michel Houellebecq “Whatever” (“Extension de la domaine de la lutte”)

And just to make it a trifecta of sexual Eeyorishness, there’s always Schopenhauer.

Baby boom

June 1958 – September 1962

Malthusianism does a pretty good job of capturing the facts of life for our species before the Industrial Revolution. For example, Malthus plus standard economics helps account for some of the historic differences between wheat and rice growing societies. And Darwinism suggests the reason why Malthusianism holds for living things in general: within a population, variants with a higher intrinsic rate of increase tends to replace those with a lower rate, even if the eventual outcome is overpopulation and misery for all. So the field of human behavioral ecology, based on the assumption that people try to maximize fitness, does pretty well in accounting for behavior in pre-modern societies.

But Malthusianism, and the assumption that people are fitness-maximizers, don’t work very well for modern societies. Even as life expectancies and standards of living have been increasing around the world, fertility rates have been declining, falling below replacement levels even in many less developed countries (although rates remain quite high in Sub-Saharan Africa.) The United States mostly follows the general trend, with a long decline in fertility rates over several centuries.

And then there’s the Baby Boom: Birth rates in the United States went up dramatically following the Second World War, then reached a peak in 1957, and continued high into the early 1960s. Young people were marrying early, and having more children. Women were staying out of the workforce to take care of the kids.

baby boom

Here are two popular theories of why the Baby Boom happened that don’t work:

Soldiers coming home. The return of soldiers from the Second World War contributed to an early spike in the birth rate. But the boom lasted too long to be mostly explained this way, and involved a big increase in the total number of babies born, not just people getting around to having babies that they’d put off having earlier.

Women squeezed out of the labor force. Increasing employment and educational opportunities for women are one of the long-term drivers of the demographic transition. So were these factors operating in reverse during the Baby Boom? The data clearly rule this out. Women’s wages actually rose rapidly during this period, and older women, with their child-rearing years mostly behind them, responded by entering the labor market in large numbers. In other words, employers were eager to hire women, but young women, at least, thought they had better things to do.

Instead, the best account we have comes from Richard Easterlin. He proposes that the Boom happened because young men encountered an exceptionally favorable labor market, resulting from the conjunction of several factors. (1) Birth rates fell to low levels during the Great Depression, naturally enough. As a result, twenty years on, employers faced a shortage of native-born young men looking for entry level jobs. (2) In the nineteenth century, periods of high demand for labor saw increases in immigration; levels of immigration tracked the business cycle. But in the mid-twentieth century, legal restrictions made it difficult to increase the supply of labor through immigration. Employers instead had to offer higher wages for entry level workers. Young men felt they were doing well enough – both absolutely and relative to the older generation – to get an early start on marrying, and to support their wives while raising bigger families.


The Baby Boom would be its own undoing however. As the earliest Boomers grew up and started to crowd the job market and the universities, “The Sixties” took off.

Half the sky

February 1949 – October 1953

Chinese state patriarchy – the alliance of the Emperor and his officials with patrilineal extended families and clans and patriarchal authority, under the sign of Confucius – was extraordinarily resilient. Over the course of several thousand years, it bounced back again and again in the face of foreign invasions, and neutered potentially disturbing influences like Buddhism and Christianity and the growth of mercantile wealth. It was finally severely weakened, if not quite eliminated, in the twentieth century. Chinese intellectuals, including the student reformers of the May 4th movement, regarded the traditional Chinese family system as a source of backwardness, which would have to be overthrown for China to take its rightful place among the world’s powers. After the Chinese Communists took over in 1949, they promulgated a revolutionary new marriage law (1950), which stated, in part

The feudal marriage system, which is based on arbitrary and compulsory arrangements and the superiority of man over women and ignores the children’s interests, shall be abolished.

The New Democratic marriage system, which is based on the free choice of partners, on monogamy, on equal rights for both sexes, and on protection of the lawful interests of women and children shall be put into effect.

Bigamy, concubinage, child betrothal, interference with the re-marriages of widows, and the exaction of money or gifts in connection with marriages, shall be prohibited.

Marriage shall be based on the complete willingness of the two parties. Neither party shall use compulsion, and no third party shall be allowed to interfere.

(The law, however, allowed traditional rules of exogamy to stand. These required people to marry outside their clan.) A campaign began, launched in 1953, to enforce the new law. The Communists in China would prove willing to use extraordinary violence to attack old ways, including a kinship system that stood in the way of new forms of state power.